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DICKEYBIRD
05-27-2012, 12:45 PM
I got a little work done on my 1983 Denford ORAC CNC lathe retrofit project so I figured it’s time to start a thread. It won’t be completed anywhere near as quickly as Jim’s but maybe it’ll keep me motivated to keep plodding forward. This was an eBay purchase that came with no electronics whatsoever other than the original Pioneer audio cassette player & speakers. It was a training lathe, eh?

I got the original ORAC cabinet with mine and decided to put everything I could inside of it other than the PC. The top of the cabinet is heavy gauge metal but was unsupported from the underside. The paint was fretted off under the lathe mount pads so there was definitely flexing going on. My solution was to bolt on some cross-wise angle iron braces to the top & bottom panels with vertical struts tying them together. The bottom panel already had heavy gauge lengthwise channels spot welded on underneath so once everything was bolted up, it's very stiff.

http://i57.photobucket.com/albums/g227/DBAviation/TrayIn.jpg

http://i57.photobucket.com/albums/g227/DBAviation/LBrace.jpg

http://i57.photobucket.com/albums/g227/DBAviation/RtBrace.jpg

I figured I’d be putzing around with electronics for quite some time during the ironing-out-the-kinks phase and would need free access to everything so I decided to build in a slide out tray that could do double duty as a mount platform for the gear and a big heat sink as well. The 14” x 18” piece of 15mm aluminum slab was one of several big chunks that were given to me a few weeks back so luckily I didn’t have to spend any cash on it. A couple hardware store drawer slides and some brackets had it sliding in & out effortlessly. This picture shows a mock up of approximately how the gear will be mounted.

http://i57.photobucket.com/albums/g227/DBAviation/TrayOut.jpg

The tray had to be mounted on an angle to clear the cabinet’s angled upward front so everything except the contactor barely clears the top as it’s slid out. I was thinking of mounting the contactor horizontally but decided to add a tab to the bottom of the front of the slab to drop it down & position it vertically as recommended by the manufacturer. I’ll wait ‘til the final config. is decided on before finishing the mount.

outback
05-27-2012, 03:59 PM
Milton;

The green circuit board with the orange teminal blocks,,,what is it going to do?

I'm salvating over that aluminum plate.

Jim

DICKEYBIRD
05-27-2012, 04:32 PM
That's the famous (cough, cough) SmartStep/3 controller made in Bristol England in the 90's. It does 3 axes, 2 amps @ 40v, 1/2 step. I have one on the MicroMill and this is its spare. I pull off the proprietary serial interface board & connect directly to the step & direction pins. Works pretty well on appropriately sized steppers. I've spent so much on bits & bobs for this project I'm going to try to make do with it to save a buck. If it fails miserably, I'll save me pennies & get something else later.

I got lucky a few weeks back and a neighbor gave me that piece of plate, another one almost twice as big and a bunch of smaller pieces 4" to 6" wide by a foot long plus some good size chunks of stainless plate. It was test jigs & fixtures that were obsolete and were stacked up to go to the dumpster where he works.:eek: It doesn't happen often but I do get lucky once in a while.:)

outback
05-27-2012, 06:28 PM
Sounds like a driver board that does 3 axis's, Hmm, never heard of it but if it saves you from buying 2 or 3 Gecko drivers that is a $300 to $450 savings.

So, the board with the blue terminal blocks must be the breakout board right? Looks a little like a Bob Cambell breakout board.

I'm in the market for another breakout board. Something kinda simple to run my CNC indexer as a stand alone.

I need to buy some scrap aluminum plate just for stock. I just love buying scrap metal then reselling it for full retail plus 10%. I few times I have had
FREE scrap and resold it at full retail. Couple of times it was to the same people that gave me the scrap metal in the first place. Before I retired the place gave me all kinds of junk. Couple of times I built little projects from junk I brought back to work from home. They could never figure out how I made stuff for them without spending money on materials. Now the place I retired from is my best shop customer so I often sell them back their own junk.

Here is a small 3 axis milling machine I built from stuff that was given to me.
The steppers, castiron for ways was all FREE. I bought the spindle motor on Ebay and the Ballscrews from Rockford Ballscrew.
FREE MILL (http://img.photobucket.com/albums/v30/jglass/CNC%20projects/CNC%20%20Mill%203/MillDone.jpg)

Life is good!
Jim

DICKEYBIRD
05-27-2012, 06:55 PM
Yep, it's a CNC4PC C11 B.O.B. http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=161

It does spindle speed control, relays, opto-isolated, etc. One of the few brand new parts in this project.

I'm with you on the re-purposing junk. Everything I build has some previously used content. Couldn't afford it otherwise.

DICKEYBIRD
06-06-2012, 11:13 PM
I had some extra shop time (4 well-earned days off from the day job) so I made some more progress on the ORAC. SWMBO has been ill so I wasnít able to really get after it. I was thinking Iíd have it running by now but dang Iím slow!

The big olí Baldor motor wouldnít quite go where the original motor did so I had to use a few redneck engineering tricks from my hotrod days. I hacked a hole in the back panel and cobbled up some angle iron brackets to mount the motor out on tíback porch. I figure itíll need an idler to dampen belt oscillations before allís said & done.

I got 2 taper lock sheaves to fit the motor from Motion Industries. I originally planned to make a couple but man, after seeing these and seeing how well they work, Iím so glad I didnít attempt it. One should give it about 1500 rpm tops and the other about 2200. Iíll probably never need 2200 but I have it on hand if required.

http://i57.photobucket.com/albums/g227/DBAviation/BeltGash.jpg

http://i57.photobucket.com/albums/g227/DBAviation/MotorMount.jpg

I made a front panel to close up the big hole in the front from a piece of 13 gauge sheet Iíve had in the shed for years that had one broken over edge to make it nice & stiff. It was way too big but I was able to cut it to size without warping by using an abrasive metal cutting wheel in my table saw. Cut like buttah! A few holes for the switches, a coat of rattle-can black & it looks pretty decent.

Oh yeah, the hinge on the bottom has a story too. A friend cleaned out a garage for a church member whose husband had passed away. In it was a box of probably 100 lbs. of aircraft panel hinges. I assume they're for access panels of some sort. My friend looked up the part # on the box and they go somewhere on a B727. Theyíre 7075 alum. and are primed with a paint thatís unbelievably tough. Plenty good for my ORAC!

http://i57.photobucket.com/albums/g227/DBAviation/PanelClosed.jpg

http://i57.photobucket.com/albums/g227/DBAviation/PanelOpen.jpg

DICKEYBIRD
06-06-2012, 11:14 PM
Whatís really soaking up the time is the electronics. Thatís my weakest area. I made pretty good progress today as I got all the main components juggled into their best locations and permanently mounted. I got the contactor latching circuit working (finally) the PC power supply modified & working, the DIN rail with terminal blocks & fuse holders hooked up, the relay for the speed control hooked up and most of the ďbigĒ wiring done. My sliding components drawer added a little extra work as I had to make sure nothing hangs up while moving it in & out and also mounted in a manner that minimizes flex & fatigue. I gotta thank macona for steering me to the DIN rail system. I love it!

http://i57.photobucket.com/albums/g227/DBAviation/Electrics1.jpg

http://i57.photobucket.com/albums/g227/DBAviation/Electrics2.jpg

http://i57.photobucket.com/albums/g227/DBAviation/PwrSupply-Xfmr.jpg

http://i57.photobucket.com/albums/g227/DBAviation/Switch-Fuse.jpg

DICKEYBIRD
06-06-2012, 11:15 PM
I have a question concerning grounds. Iíve seen some threads where machine grounding can get very contentious and nasty. I donít want to get that deep & esoteric but hereís what Iíve done so far. I checked the wall socket that the machine will be plugged into with one of those gizmos that checks the magic smoke to make sure the neutralís neutral, the hotís hot and the ground is good. It passed with flying LED colors.

My power cord comes into the machine through a proper strain relief device, the hot wire goes across a 15 amp fuse holder, a SPST 20 amp switch and on to the contactor. The neutral wire goes straight to the terminal block where it splits off to each device as needed. The ground wire in the power cord goes to a stud in the enclosure and onward from there to a stud on the sliding tray. The ground from the PC pwr supply on the tray goes to that stud as well. I made sure that all connections were bright & shiny with the fasteners torqued properly. Does that sound reasonable & safe?

http://i57.photobucket.com/albums/g227/DBAviation/ChassisGround.jpg

http://i57.photobucket.com/albums/g227/DBAviation/TrayGround.jpg

Tomorrow I hope to get into hooking up the CNC4PC C11 breakout board and the stepper connections with the motors off the machine and clean up that mass of wires coming out of the power supply. Hope so anyway.:)

MaxHeadRoom
06-06-2012, 11:35 PM
Normally a central star ground point is set up where all bonding conductors and shields would be connected to, together with the service ground.
http://www.automation.siemens.com/doconweb/pdf/840C_1101_E/emv_r.pdf?p=1
Max.

DICKEYBIRD
06-07-2012, 11:04 AM
Thanks again Max, as always. I've saved that document for reference. Talk about drinking from a firehose!

Actually it's mostly understandable...even by me.:) It looks like what I've done should be OK.

So far it switches on, the cabinet fan spools up, 24VDC pwr supply powers up, the contactor pulls in & latches with a press of the start button, PC power supply comes on, controller transformer powers up, , etc and it all goes away with a whack of the E-stop button. No tingles felt when touching any metal parts of the cabinet or tray. So far so good.:)

The controller power transformer worries me a teeny bit though. It's supposed to be 24 or 28V but the open circuit voltage is 27.4 and 31.4, about 1V higher than the xfmr manufacturer's stated O.C. voltage. I know it'll drop under load but I sure don't want to fry the controller. Max input voltage for it is 28VAC. I'm going to initially connect it at the lower setting and check it under load then go to the higher setting later if all's OK.

ps: Boo hoo, gotta go back to work tomorrow and wade into the stinky pile that'll for sure be lying on my desk.:(

outback
06-09-2012, 05:40 AM
Milton;

Looks like you are making great progress. Wish I had the lathe base like you have for the electronics.

I bought a couple of Optek OPB917B sensors for my lathe so I can do threading with Mach3. Probably the same sensor you are going to use. I'm tied up these days with paying jobs so the threading project is on hold for now. Sometimes I feel I'm held prisoner in my own shop.

Threading with stepper powered spindle is not going to pan out. To slow and not enough power for threading steel.

I have a 1/4 hp Baldor 90VDC motor just like the one you have that I would like to find a good home for. It was running my small CNC milling machine but 1/4hp was just not enough power so I went to a 1/2hp Baldor, probably the same as yous.

Jim

DICKEYBIRD
06-09-2012, 10:04 AM
I bought a couple of Optek OPB917B sensors for my lathe so I can do threading with Mach3. Probably the same sensor you are going to use. I'm tied up these days with paying jobs so the threading project is on hold for now. Sometimes I feel I'm held prisoner in my own shop.

Threading with stepper powered spindle is not going to pan out. To slow and not enough power for threading steel.

I have a 1/4 hp Baldor 90VDC motor just like the one you have that I would like to find a good home for. It was running my small CNC milling machine but 1/4hp was just not enough power so I went to a 1/2hp Baldor, probably the same as yous.I know what you mean about the paying job thing. For me this was supposed to be a hobby but last year things changed a bit and now it varies from all-out, every spare minute thrashes to complete a big project to multiple little jobs that eat up evenings & weekends. I need the money too much to tell 'em all to go away though. I've got 2 paying projects and a carb rebuild for my edger "in the holding pattern" right now but I'm trying to stay on the ORAC at least through tomorrow night before I getting started on them.

I got the sensor & C3 board hooked up last night although I haven't made the slotted disc yet. The little LED on the C3 flashes on & off when I pass a matchstick through the sensor so I know it works. How does your sensor talk to Mach? Does your B.O.B. have the circuitry built in or are you going to build your own little board?

Sorry to hear about the stepper/spindle/threading thing not working out, that was a very interesting experiment. A decent used servo might do the trick eh? Then you'd have to get a drive and learn how to tune a servo though.

My Baldor DC motor is actually 3/4 hp. I waited until a good deal came up on eBay and snapped it up. I can't wait 'til I get the ORAC running & see how well it peels off the metal!

DICKEYBIRD
06-11-2012, 11:36 AM
Gettin' closer! Got the B.O.B & the controller powered up yesterday and finally got the stepper motors spinning in the proper directions. Yay!

The motors were initially making the appropriate sizzling noises and warming up slightly but would only go "clunk" and move a tiny bit when trying to jog. I beat my head against the wall for quite a while until I back-tracked the wiring and found I had the step/direction connections reversed.:rolleyes: They work smooth & quick now and have great torque & holding power as compared to my previous CNC projects. Thanks again George (Sparky NY) for the stepper help; they're great!:)

Question: I bought shielded motor wiring; the info I've been able to find says the shield should be grounded on 1 end only. Is that correct and does it matter which end? It'll be easier to hook up on the controller end in my installation.

I also got the monitor post mounted. I found an inexpensive but sturdy swing-out monitor mount bracket that bolts to the post and positions the monitor above the center of the back panel and swings to the left for viewing when the ORAC's next door neighbor MicroMill is being used.

Oh yeah, another re-purposing thing: The hookup wire for this project came out of my old 80's era Maytag washer. Before it was hauled away by the big box store, I stripped all the wiring, solenoids, nuts & bolts, grommets, power cord, strain relief, etc out of it. There were half a dozen different colors of good quality stranded 16 ga wire in it. I was able to use a few of the factory crimped connections as well. Being a Maytag product, the wiring will never need service!:D

Won't be long now 'til I get to building the stepper motor mounts and hooking up the speed control & motor stuff.:)

MaxHeadRoom
06-11-2012, 04:14 PM
Question: I bought shielded motor wiring; the info I've been able to find says the shield should be grounded on 1 end only. Is that correct and does it matter which end? It'll be easier to hook up on the controller end in my installation.


At one time it was stressed that shielded cables be grounded one end only, one reason to prevent ground loops.
If you refer to that Siemens PDF section 6 you will see there has been a recent change of thinking and both ends of a shield can be connected to ground, but this also should go hand in hand with what is called equip-potential bonding, (also in the PDF) which in plain language is using ground or bonding conductors to metalic parts of the machine and motor frames to ensure that all parts of the machine are at ground potential, this is especially important when using low signal equipment that operates at the 5v or TTL level.
Max.

John Stevenson
06-11-2012, 05:03 PM
I'm one stage forward of my Orac conversion.

got a phone call beginning of last week and asked if I would collect the Orac from storage as they need the space.

And just by a small coincidence I now have just a bit of space now that I have shifted the TOS out :o

Didn't really need it at this stage but 3 years free storage in a heated warehouse isn't all bad.

DICKEYBIRD
06-12-2012, 09:56 PM
I'm one stage forward of my Orac conversion.Uh-oh, I better turn up the wick. You'll have yours going in no time.:eek:

Didn't get much done tonight. 11 hrs at the day job, came home & had to clean out the fuel tank and rebuild the carb on my lawn edger after supper. Like my pappy used to say: "Son I'm plum tuckered out."

I did come up with a name for it though while I was in the shower washing off the gas stink. Ya'll do name your machine projects don'cha?

Cyrano de Lathe-ORAC :D



Was that a chorus of groans I just heard?

DICKEYBIRD
08-20-2012, 02:40 PM
Been a while since the last update but it’s getting closer! Got the stepper motors mounted, wired up & working smoothly after a bit of screw-up on the X-axis cable splice job. The Z-Axis mount will hopefully pass the Sir John flimsy stepper mount test but the X-axis will surely fail. My only excuse is the 2A/40V British SmartStep/3 driver underpowers the NEMA 23 stepper motors enough that surely there won’t be much mount flex going on. It sure feels strong enough for the job though. If I ever move up to real manly-man steppers and drivers, I’ll redesign it then.

Got the CNC4PC C3 spindle index card & sensor wired up, sensor disc installed and tested…dead nuts accurate rpm readings verified by stopwatch. The ĺ hp Baldor DC motor’s up & running and under Mach control…FINALLY! I had a terrible time getting the CNC4PC C11 to play nice with the KBIC-120 speed control. The instructions with the C11 were too vague for me to get a handle on and apparently I don’t understand the isolation concept well enough. I dutifully hooked it up with 3 different power supplies as instructed but killed 1 KB control (there must be a Darwin award for that feat) and vaporized a track on the C11 card during 3 weeks of off & on cussing & fretting.

I finally read the KB manual more closely, followed their instructions and found a KBSI-240D Signal Isolator board on eBay for $35.00. Bingo, instant success! I now have Mach commanded speeds across the range within 10 or 15 rpm. As a bonus, the KBSI hook-up instructions clearly showed how to install a switch to easily revert back to manual speed control via 5K pot when desired.

http://i57.photobucket.com/albums/g227/DBAviation/DriveEnd.jpg

http://i57.photobucket.com/albums/g227/DBAviation/ORAC1.jpg

The SCR KB control/Baldor motor humming noise drove me crazy pretty quickly though as the motor was solidly bolted down to brackets connected to the sheet metal enclosure. That thing was acting like a big speaker and the 120 hz. (I think) hum was intolerable. In a flash of inspiration, I remounted the motor to the mount with 4 rubber insulators that came off of SWMBO’s parted-out treadmill and VOILA!….noise gone. I wasn’t able to get the belt tight enough since the mounts are a bit soft so I rooted around and found a rubber block to jam between the motor endbell and the machine enclosure. It works perfectly! I added an idler pulley on the slack side to control the little bit of belt whip I was getting at particular speeds and now I’m happy with it. It’s whisper quiet now. Oh yeah, the idler pulley came off a Land Rover Discovery from a years-ago factory recall so it fits the British machine theme well. Never understood why they recalled them but we dutifully fitted new ones by the bazillion. I had a box full of the old ones and either used them here & there or gave them away and this is the last one. Never heard of one failing.

http://i57.photobucket.com/albums/g227/DBAviation/MotorMount2.jpg

I finalized the electrical components tray and it all stays cool as a cucumber after hours of static testing other than the contactor which gets up to about 110 F. I think that’s OK. The little inline fuseholder on the bottom right bridges the vaporized track on the C11 and probably needs to be a production update for electronically challenged buyers like me. I found numerous other users online that had had the same problem or worse when trying to hook theirs up.

I added a 12V muffin fan and heatsink to the bridge rectifier on the SmartStep board after the one on my MicroMill overheated and died last year. It cools the KB as well.

http://i57.photobucket.com/albums/g227/DBAviation/Electrics4.jpg

DICKEYBIRD
08-20-2012, 02:42 PM
Another example of re-purposing “stuff” I had in stock for the project was the protective sheath I cobbled up for the X-axis stepper motor. It’s made from the braided stainless cover off of some old clothes washer water hoses I saved. A few minutes with a cutoff wheel and I had the sheathing off and I was able to roll the ends back for a smooth fit. I turned & milled some fittings from aluminum scraps and added a couple pieces of heatshrink and tie wraps to secure the ends. The carriage moves from end to end now with no hang-ups or kinks of the cable.

http://i57.photobucket.com/albums/g227/DBAviation/CableSheath.jpg

http://i57.photobucket.com/albums/g227/DBAviation/CableSheathFittings.jpg

http://i57.photobucket.com/albums/g227/DBAviation/CableSheathEnd.jpg

I finished the “set-tru” adjustable ER32 collet chuck this weekend and it works great! The chuck flange I.D. is larger than the tapered spindle flange snout which allows a bit of adjustment while tightening the chuck mount nuts via 4 brass tipped screws bearing on the snout. The snout taper is a smidge over 7 degrees so I set up the chuck in the mill vise at that angle to drill & tap it 10-32. It really works nice other than you have to get used to the adjustments being bass-ackward from a 4-jaw. I use a 4-jaw a lot and it’s hard to change me ways.

http://i57.photobucket.com/albums/g227/DBAviation/AdjChuck-1.jpg

outback
08-20-2012, 04:31 PM
Nice job Milton

Jim

John Stevenson
08-20-2012, 05:42 PM
Update.

Mine has landed on a bench !!

Don't panic because I wanted the hydraulic lift table it was parked on. When the table is free it's going back into the holding pattern. :rolleyes:

DICKEYBIRD
08-20-2012, 08:38 PM
At least it's in the general area of the workshop though, right? Rejoice, a major milestone! :D

DICKEYBIRD
09-23-2012, 07:26 PM
Didnt have to work at the real job yesterday so I had some time between yard duties to get a few more things done on Cyrano de LatheORAC.

Got the 5/8 x 4 x 11" steel extended tool plate finished & mounted. This repurposing of stuff I have lying around is getting downright scary. If anyone has tried to find the little 6mm tee-bolts that fit a Compact 8's carriage slots you'll know how ecstatic I was to find that the bag of ZF transmission pan screws I had on hand fit absolutely perfectly after milling off 2 sides to get the width down to 10mm. They were easy to make once the mill was set up for them so I made extras and decided to use 6 to hold the plate down as a bit of overkill.

They are cad plated and very strong plus the wide head's thickness is perfect for the slot. The guys at work replace them all the time due the torx size increase of the later style ones prevents stripping out and they give the old ones to me.

The tool plate is designed for 2 QCTP's and I drilled & tapped 3 holes for the rear post to allow some room for adjustments The 3 button-head screws are removed to oil the ballscrew and the slides without too much hassle. I put on 2 sheet metal covers to keep swarf out of the works. I hope the twin QCTP thing works OK in the real world. I was going to just mount a single dedicated rear cutoff blade holder but then decided a 2nd QCTP will make it more flexible (I hope!) Haven't procured #2 yet but should pretty soon when the check arrives for a paying job I finished a couple weeks ago.

http://i57.photobucket.com/albums/g227/DBAviation/ToolPlateTeeBolts_zps6c3bbfa0.jpg

http://i57.photobucket.com/albums/g227/DBAviation/ToolPlate_zps80ea6113.jpg

http://i57.photobucket.com/albums/g227/DBAviation/ToolPlate2_zps17e806e3.jpg

I knocked out a tommy bar and spanner wrench extension bar to make it easy to put the grunt on the ER32 chuck collet nut. The extension is just a piece of 1/2" conduit flattened on one end and hammered onto a standard length wrench with a rivet made from a soft nail to lock it on. Using those 2 and the Maritool bearing equipped collet, I can squeeze the cr@p out of the work.

http://i57.photobucket.com/albums/g227/DBAviation/ERChuckTools_zps1cc24d67.jpg

DICKEYBIRD
09-23-2012, 07:37 PM
Another repurposing head shaker moment I had was during the process of installing the drive end/belt cover. I had to hack it up a bit to fit the new belt drive arrangement and once that was done I started looking around the shop for a piece of sheet metal to make a replacement end cover since the original wasn't supplied with the lathe.

Lo & behold, in my pile of stuff I found a piece of 1/8" clear anodized brushed aluminum with a bunch of holes around the perimeter. With the good side out, I tried it and the width matched perfectly and the holes on 3 sides aligned perfectly with the flanges on the cover! Had to cut the piece to length, cut the notch, dress the edges, drill 5 holes in the cover and drilled & tapped the flanges for a perfect fit. Freakin' scary. I bought that piece 4 yrs. ago for $1.25 in a yard sale.

http://i57.photobucket.com/albums/g227/DBAviation/BeltCover_zps06e698e6.jpg

http://i57.photobucket.com/albums/g227/DBAviation/BeltCover2_zps1c3e2093.jpg

I'll make a can to cover the stepper motor later...or not.:D

outback
09-24-2012, 07:35 AM
Milton;

You are certainly going to have a nice lathe there.

I sure like mine. I never realized how great it is to have a nice small lathe for
real small work. I needed to drill some .030 diameter holes yesterday so I used the G83 code for peck drilling. That worked great and the machine did all the work and I never broke a single drill.
Jim

DICKEYBIRD
09-24-2012, 01:08 PM
Awesome, .030" holes...that's some finesse right there! That tiny little drill would want to see some high spindle speeds.

Q1: Did you just dial the VFD way up or do you have a toolpost mounted high-speed spindle of some sort?

Q2: How did you adjust to make sure the bit was dead-center? I've got a job coming up where I plan to use my 5/8" straight-shanked ER16 chuck mounted in a QC boring bar holder and was curious what the best way to get it adjusted on center before zeroing the axes.

"I sure like mine. I never realized how great it is to have a nice small lathe for
real small work." Unfortunately it's the biggest lathe I have in my shop!:(

outback
09-25-2012, 05:13 AM
Q1: Did you just dial the VFD way up or do you have a toolpost mounted high-speed spindle of some sort?

I just dial up the VFD and that was still way to slow. The .030 holes were only 080 deep. I used a .002" advance per peck. Took a while but at least I didn't
have to stand there and do it. CNC is a perfect application for small hole drilling because the system knows exactly where the work is and where the tool is. For manual drilling we look for "Tool Feedback" to know when the tool found the work. This is how small drills break.

Hmmmm....A highspeed spindle, now that sounds like another interesting project.
I wonder if one of those little airgrinders mounted to the toolpost would work??


Q2: How did you adjust to make sure the bit was dead-center?

Mounted a dial indicator in the lathe chuck then indicated in the drill chuck. Kinda like indicating in a hole in the milling machine except doing it horizontal.

Here is what the job was (http://img.photobucket.com/albums/v30/jglass/CNC%20projects/CNC%20Lathe/picuptools.jpg) The large diameter of those parts is .452" and I made 5 of each

Jim

DICKEYBIRD
09-25-2012, 08:26 AM
Hmmmm....A highspeed spindle, now that sounds like another interesting project.
I wonder if one of those little airgrinders mounted to the toolpost would work??Probably would but I'm not sure how good the runout is on those.

I've been thinking about something like this to use on my little MicroMill for engraving and on the lathe for tiny hole drilling http://www.ebay.com/itm/High-speed-300W-ER11-12-48V-DC-Spindle-Motor-for-CNC-Engraving-Milling-Grinding-/271060040592?pt=LH_DefaultDomain_0&hash=item3f1c6ffb90 but again, how good can the runout be on something that cheap?

outback
09-25-2012, 10:04 AM
I would like to have that motor just to drive the high speed spindle I'm thinking
about making. It is going to happen today if I have the components on hand. I just love being unemployed. I'll need to work like heck before the phone rings.

I plan to run a spindle with a small drill chuck mounted on one end. Then have a small electric motor or small air grinder run the spindle with a belt.

Need to be real careful running high speed AC motors around the stepper motors on the lathe. There can be cross talk between a AC motor and a stepper, don't recall the technicle term for such phenomena. I have seen it before and the only cure was changing out the 10,000 RPM AC motor with a DC motor. That 10,000 RPM motor would have been nice have, still have it. This was on my first CMC milling machine.

Stay tuned, Jim

DICKEYBIRD
09-25-2012, 10:20 AM
Awesome!

I picked up a CTC ER16/10mm x 100mm straight shank collet chuck a while back with the intentions of adding some decent bearings and make a little high speed spindle but havn't done it yet. I think ER11 or ER16 should be more accurate than a drill chuck (unless it's a good 'un) and I already had a set of ER16 collets.

Cheap DC motors and controllers of the right power are fairly cheap these days.

Rosco-P
09-25-2012, 10:27 AM
When all is said and done, how much in materials (base machine, raw materials, motors, computer gear, misc. electronics, software, etc.) will the CNC lathe build have cost you? I realize that some of parts will have come from creative scrounging, but try and price it as if all was purchased.

If we could, lets avoid the comments that say, "The experience of building your own CNC lathe or mill is priceless."

DICKEYBIRD
09-25-2012, 10:50 AM
When all is said and done, how much in materials (base machine, raw materials, motors, computer gear, misc. electronics, software, etc.) will the CNC lathe build have cost you? I realize that some of parts will have come from creative scrounging, but try and price it as if all was purchased.

If we could, lets avoid the comments that say, "The experience of building your own CNC lathe or mill is priceless."What difference does it make? It pleases me to build it up at my own pace with the funds I'm able to spare as I go along and that's fine with me.

Rosco-P
09-25-2012, 10:56 AM
What difference does it make? It pleases me to build it up at my own pace with the funds I'm able to spare as I go along and that's fine with me.

Well the question was a genuine one. I was interested in the price of conversion, if you had kept track of the cost.
It wasn't meant as a slam of the time spent or the end result.

But thanks anyway.

legendboy
09-25-2012, 11:19 AM
Nsk make really nice small high speed spindles suitable for drilling and milling

DICKEYBIRD
09-25-2012, 11:21 AM
Oops, sorry it sounded like you were implying that I was wasting my time and would have done better to just go buy one.

I have a pile of receipts in a drawer and haven't added them up. I will add it up at some point because I'll have to determine it's value come tax time. I'll be happy to post it then but don't want to mess with it right now. Too busy trying to get it working properly.:D

Rosco-P
09-25-2012, 11:40 AM
Oops, sorry it sounded like you were implying that I was wasting my time and would have done better to just go buy one.

I have a pile of receipts in a drawer and haven't added them up. I will add it up at some point because I'll have to determine it's value come tax time. I'll be happy to post it then but don't want to mess with it right now. Too busy trying to get it working properly.:D

No, not at all. As I recall, before you had your lathe working at the stage it is now, it was already doing paid work for you.

Looked at several similar (or not?) Emco 5 lathes; either derelict and sitting idle in a school; at a dealer for big bucks, one in the hands of a retired machinist who was having troubling getting it to work, little support. Wondered about their capabilities, as is or as a platform for update. Would like something with a tool turret like this: http://www.lathes.co.uk/wade/page7.html But for the price I don't think I'd have enough work to keep it busy.

DICKEYBIRD
09-25-2012, 01:34 PM
No, not at all. As I recall, before you had your lathe working at the stage it is now, it was already doing paid work for you.

Looked at several similar (or not?) Emco 5 lathes; either derelict and sitting idle in a school; at a dealer for big bucks, one in the hands of a retired machinist who was having troubling getting it to work, little support. Wondered about their capabilities, as is or as a platform for update. Would like something with a tool turret like this: http://www.lathes.co.uk/wade/page7.html But for the price I don't think I'd have enough work to keep it busy.Actually this Denford ORAC was bought with some of the proceeds from the big job I did with the homemade add-on lathe spindle on the little Denford CNC MicroMill I posted about elsewhere. If I could get this one to produce the same dollar investment/return ratio that the other one did I'd be one happy camper!

I was actually looking for an EMCO C5 or C6 CNC lathe when I found the ORAC. Those are some neat little lathes especially with the tool changer. There's a few around here & there but typical for EMCO they're real high-priced. They're expensive to buy and the parts are even more so. The fellow I got my ORAC from in Detroit has some EMCO stuff but I'm glad I got the ORAC as it's bigger and sturdier than the C5 plus the bed, carriage & spindle are almost exactly the same as my middle 80's Taiwan 8x16 clone of the EMCO Compact 8 so all my tooling works great on either one.

You might look around for a Prolight 3000 like in this thread http://madmodder.net/index.php/topic,7545.0.html They look really good with a 5C collet spindle, ATC, 1 hp DC motor & controller & a decent enclosure. One guy got one from a school auction for $25.00! Makes me GREEN with envy. The stepper motors are a bit puny but they could be replaced along with installing modern drivers and it'd be a great machine. Wish I'd known about those a lot earlier. There are other types that should be available reasonably priced as well.

outback
09-25-2012, 04:05 PM
Rosco;

I also did a retrofit on an Orac lathe. Actually Dickeybird told me about the lathe I ended up buying. It was in Michigan about 300 miles from where I live in Illinois.

I paid this guy $1100 for the lathe bed and head, 3-jaw chuck, 1/2hp motor and
tailstock. The ballscrews were already on the lathe.

I needed to supply 2 stepper motors which I already had and the CNC controller. A relative gave me a computer and monitor, they said it had a virus. I reformated the hard disk, loaded software and it works great.

I think my total investment is between $1800 and $2000.

Here is a link to my retrofit:
http://bbs.homeshopmachinist.net/threads/54027-Denford-Lathe-Retrofit?p=765364#post765364

Truthfully, if you want to buy all new stuff and your time you might be farther ahead to buy a CNC lathe that is turnkey ready to go.

Milton and I took full advantage of components that are readily available and cheap. We also have the advantage of having a CNC machine that has modern components that we understand and can trouble shoot/repair ourselves. Is a retrofit for everyone, no it is not. To do a retrofit you must be able to read and follow written directions and you must be able to do criticle thinking. Then there are times when you need to ask the right questions to the right people. It is important to understand that.

My Orac lathe retrofit is my 5th CNC machine project. Not bragging but then again not bad for a guy that repeated 4th grade. Jim

John Stevenson
09-25-2012, 06:05 PM
Not started mine yet but it cost £325 form a college in Oxford. It's a complete machine and has an air chuck and also the original 3 jaw.

It's got controller problems, the motor will run and speed up but that's all. Not bothered as it was bought to gut it.
I reckon it will cost me two stepper drivers, I'll also change the motors to something more powerful and modern and also change to spindle motor and inverter to something like 2Hp to try to get constant speed when threading.

I reckon £80 for drivers, same for motors, New power supply at £50, new spindle motor at £80 and inverter at £140

Total outlay should be around £750 but I do have a fair bit of the above on stock and it's probably not cost me that.

I'll probably sell the complete casing with all original electronics and make a new stand and enclosure so these will probably balance out.

DICKEYBIRD
09-25-2012, 07:15 PM
....also change to spindle motor and inverter to something like 2Hp to try to get constant speed when threading.Early on I figured a 3/4 HP DC motor would be the dog's cajones but after seeing your 2 HP choice I'm thinking the Dayton 2 HP 3PH motor out in t'shed might get a try if I stumble into a steal on a VFD that'd work. The motors are similar in size and the mount, belt & idler are already there....hmmmm.:D Power, MORE POWER! MUHAHAHA!

outback
09-25-2012, 10:34 PM
My high speed spindle:

http://img.photobucket.com/albums/v30/jglass/CNC%20projects/CNC%20Lathe/highspeedspindle.jpg

I had that Albreck chuck mounted to a 1/2" arbor. In the pic the arbor is mounted on R8 bearings. The gizmo doing the driving is actually a Foredom spindle driven by an AC motor by a flex cable. I did not see a real good way of mounting the chuck directly to the foredom spindle so I came up with this technique. The added bonus is I can still remove the Albrech chuck and arbor and use it somewhere else.

I'll start a new thread on this in a couple of days. Jim

DICKEYBIRD
09-26-2012, 09:04 AM
That's a great tool Jim. It ought to come in real handy. You can do some grinding with it too. Man, you don't mess around!:eek:

I've got a 36V DC speed control and an ER16 collet chuck that I'd love to make something similar with if I can find a decent motor.

outback
09-26-2012, 10:40 AM
Thanks.....I had a need for this last week and there have been other times. I can change out the little chuck and 1/2" arbor for a DA300 collet chuck for grinding or milling. I could use this on a mill some day as well.

I ordered 3 little electric motors on Ebay last night. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280653704177&ssPageName=ADME:L:OC:US:3160
I think they are cordless drill motors, high torque, high RPM. I'm not real fond of the flex shaft drive I have now although it seems to work well. An electric motor with a couple of wires will be more self contained. If these little electric motors don't work out I'll figure something else out or use the flex shaft setup. Never know, this may never get used. Although, sooner or later most of the stuff
I conjour up comes in real handy.

Had fun building it and that is all that really counts. Jim

DICKEYBIRD
09-26-2012, 11:58 AM
Yeah those little Johnson motors are tough as a boot and should do fine for small hole drilling and grinding. I've used Johnson motors on electric R/C model airplanes back when the hot battery setup was still NiCads.;)

Now you've gone & got me excited about building one too. I've started looking around and found some inexpensive ACB bearings with 10mm ID and I downloaded a couple spindle design manuals from Dynomotion. Now if I can remember where I put that box of motors I saved from air suspension compressors and ABS pumps from the junk box at work. They're about 3" x 5" and have ball bearings on the drive end. Not real fast but should have enough grunt to handle a decent speed-up pulley set-up.

DICKEYBIRD
11-18-2012, 12:29 PM
Got a little more done on the Denford despite the best efforts of methylprednisolone to obliterate any normal brain processes. A tiny little wrong move in the shower last Sat. morning had me literally crawling back to bed in severe back pain. My Doc called in a prescription for me on Mon. afternoon and the stuff really affected me this time. It’s the third Medrol dose pack I’ve had in 8 years or so and thankfully it worked a miracle on the back pain within 8 hours.

The other 2 wierded me out somewhat but this one had me so mentally dark I was yelling at people at work and every time I went out to the shop at night to “relax,” within 30 min. I wanted to throw the whole mess out on the street and take up being a serial killer.

Fortunately, I took the last tablet yesterday and things are getting back to whatever normal is for me. I’ve been working on adding homing switches with the intent of making the X-axis homing process as accurate as possible. I’d previously picked up a couple of opto end stop sensors on ebay for $7.95 each with free shipping from the Netherlands…amazing price & product I think.

http://i57.photobucket.com/albums/g227/DBAviation/OptoSpecs.jpg

Had a little trouble figuring out how to mount them but here’s what I came up with. Milled a tight fitting groove in a chunk of hard plastic and a couple drops of super glue locked them in place firmly. A couple tapped holes in the end of the plastic block allows solid mounting.

http://i57.photobucket.com/albums/g227/DBAviation/XOpto.jpg

http://i57.photobucket.com/albums/g227/DBAviation/XOptoMount.jpg

I figured indexing off a stepper mounted disc would be more accurate than off the axis itself so I made up a half circle disc and mounted it on the stepper shaft.

http://i57.photobucket.com/albums/g227/DBAviation/XHomeDisc.jpg

DICKEYBIRD
11-18-2012, 12:30 PM
I made up an adjustable mount and actuator rod for a standard microswitch and got that mounted yesterday. During homing, the opto pulses away once per stepper rev but the signal stops at the normally-open circuit switch until the axis gets close to the end of travel and the plunger rod closes the switch. This feeds the signal to the B.O.B. and Mach stops travel and reverses until the disc edge switches the opto. I canít measure any variance in the zero point with a DTI so I guess the idea is pretty sound. Iím not real happy with the wiring but didnít have any connection boxes or other clever widgets to hide it. Itís on the back side away from chips and protected from above by the toolholder plate so should be OK. It may get something better later. At least the washing machine braided stainless cable sheathing works good!

http://i57.photobucket.com/albums/g227/DBAviation/XOptoSetup.jpg

http://i57.photobucket.com/albums/g227/DBAviation/XOptoFini.jpg

Now I have to get the Z-axis opto mounted and working and then do some studying to figure out Mach soft limits and coding to get it to home and back off to exact spindle center and reset itself to zero. You CNC gurus make it look so easy but EVERY step of the way to me is a struggle!

MaxHeadRoom
11-18-2012, 12:41 PM
Your not worried about unbalance with the half-moon disk?
I am not sure why you need constant rotating disk and not just an end switch?
There is an arrangement in Mach where you can series up all home switches N.C. and use them for homing, after which they are considered overtravel.
Max.

DICKEYBIRD
11-18-2012, 12:53 PM
Not real worried about balance as the top speed of the stepper motor with my system is pretty slow.

I just figured if I home to the same pulse of the stepper it would be very accurate due to the steps per rev/ballscrew ratio. I may be wrong though but at least I got it to work the way I thought it would. That in itself was rewarding.:D

DICKEYBIRD
03-06-2013, 10:53 AM
I got a little more work done on the project…a couple more things off the list.

I snagged a little weatherproof box off a piece of equipment at work before it went to the dump. It's bolted to the carriage and houses the Z-axis homing opto and a terminal block for both optos’ wiring.
I made an adjustable stop rod holder which allows easy changes of the Z home position. I didn’t want it permanently mounted at the far end of Z travel to prevent a long wait for the carriage to run all the way to the end then back to the work position each time it homes. It can easily be reset if a job comes along with long stock. The rod itself is gently held in place by a nylon screw. I figure if it over-travels for some reason, the screw will allow the rod to slip and hopefully won’t punch a hole the box.

Once both axes' homing were working, I set up the soft limits function in Mach. This prevents you from crashing into the ends of travel either from manual jogging or from the G-code. The stepper motors make an almost musical tone as the pre-programmed ramp down from full speed to stop occurs.

http://i57.photobucket.com/albums/g227/DBAviation/ZOptoBox1.jpg

http://i57.photobucket.com/albums/g227/DBAviation/ZOptoBox2.jpg


I decided to add spindle reversing which will make it easier to use the toolholders I have on hand with the front & rear QCTP system. I initially got it working OK controlled from Mach with a hefty DPDT relay switched by one of the small relays on the B.O.B. I subsequently got really worried about screwing up the G-code and frying my KB speed control by reversing directions with the spindle still spinning down so I ditched that method.

Max recommended another type of KB controller that does the reversing with onboard circuitry so off to ebay I went. Man, did I get lucky! I found a N.I.B. KBCC-125R for $65.00 + shipping and pounced on it. It has a more modern controller, an APRM-3 reversing module and a big dynamic braking resistor all mounted on a huge heat sink. A very serious piece of kit!

It was way too big to shoe-horn into the enclosure so I picked up a 4x8x12” electrical box from H.D. to put it in and mounted it on the back side. I followed KB’s recommendations & routed the control wiring in a separate conduit kept well away from mains power & the motor leads. I also added a small 12vdc fan on the bottom with vent holes at the top to allow airflow across the heatsink fins & the resistor. I will add some screening on the vent holes as soon as I get my hands on some.

It works GREAT. It smoothly & quickly comes to a stop from full speed one direction, switches direction and spins back up to speed smoothly. After adjustments, the speed tracks the commands from Mach within about 5 to 30 rpm from 150 to 1600 rpm in both directions. The 30 rpm variance is in reverse. I guess the motor timing isn’t perfectly symmetrical but hey, it’s closer than I’ll ever need!

http://i57.photobucket.com/albums/g227/DBAviation/KBCCBox2_zpsba24bbb2.jpg

http://i57.photobucket.com/albums/g227/DBAviation/KBCCBox1_zpse522dc0b.jpg

DICKEYBIRD
03-07-2013, 10:32 AM
AARGHH!!

Good thing my pistol was secured and not where I could get my hands on it easily. I'd have shot the ORAC right square in the headstock...or myself. Did some test cuts and the thing cuts crooked as a dog's hind leg. Like .006" taper in 1 inch!:mad:

I couldn't believe it and tried several times, moved the stock closer to the collet; changed from steel stock to aluminum; changed from a carbide insert to my sharpest HSS tool. No matter what I did, it cut a terrible taper. I guess the headstock must've shifted on the bed while it was strapped to the pallet during shipment or had been crashed at some point because I'm sure Denford/Emco didn't build it that way.

After supper and cooling off a bit, I took the front access panel off and found that there were 4 studs & nuts clamping the spindle to the bed, easily accessible from the front and the back. Looking closer,
I found 4 tapped holes with 10-32 allen head set screws bearing against the studs. Pretty clever methinks.

I decided to take a swing at adjusting it without a major alignment setup just to see if I could make it better. I chucked up an old auto strut shaft I had lying around, put a DTI against the far end, loosened 3 of the nuts and then tweaked the setscrews a bit. The next test cuts were down to about a half thou in the same distance. Whew, I feel better now and will do a more careful set up & adjustment this weekend.:)

Here's a pic of the adjustment screws. I'll definitely be doing this to my Taiwan C-8 clone if it gets taken apart for repairs!

http://i57.photobucket.com/albums/g227/DBAviation/SpindleAdjust_zps6467680e.jpg

DICKEYBIRD
07-14-2013, 01:14 PM
I guess I now have enough interesting stuff done on the ORAC project to post an update to the thread. The internet will probably be a thing of the past before this thing is finished.

I decided that a tach–generator feedback signal into the KB speed control would stabilize the spindle speed and help Mach do a better job of threading with its single pulse/rev indexing. KB says 1% variation over its 50:1 speed range using tach feedback which sounded like it was worth the trouble. Sir John’s advice to run the spindle on a 20 hp motor is a tad rich for my blood so I picked up a used 7V/1000 rpm Servo-Tek tach for peanuts on ebay and cobbled together the nec stuff to mount & drive it off the back end of the Baldor.

http://i57.photobucket.com/albums/g227/DBAviation/TachFini1_zpsb36e936f.jpg (http://s57.photobucket.com/user/DBAviation/media/TachFini1_zpsb36e936f.jpg.html)

http://i57.photobucket.com/albums/g227/DBAviation/TachCoupler_zps919afc31.jpg (http://s57.photobucket.com/user/DBAviation/media/TachCoupler_zps919afc31.jpg.html)

I made the acetal motor adapter coupling on the ORAC (1st useful CNC lathe part) using a Mach wizard. Piece o’cake putting that radius in using the wizard. The bore to match the motor shaft was done using a 2 flute endmill in the ER16 chuck. It was drilled with the endmill & then stepped over to the final bore ID. Piece o’cake and the thing slides on & off with an almost airtight fit! I love this CNC stuff! The coupler is just a bit of soft rubber tubing with a couple o-rings slid on to make sure it doesn’t slip. All this stuff worked so well I couldn’t believe it but don’t worry, you guys that know me well won’t have to wait much longer for the obligatory ‘orrible crash story.

http://i57.photobucket.com/albums/g227/DBAviation/TachAdapter1_zpsff95940f.jpg (http://s57.photobucket.com/user/DBAviation/media/TachAdapter1_zpsff95940f.jpg.html)

http://i57.photobucket.com/albums/g227/DBAviation/TachAdapterBore_zps80a4f469.jpg (http://s57.photobucket.com/user/DBAviation/media/TachAdapterBore_zps80a4f469.jpg.html)

DICKEYBIRD
07-14-2013, 01:15 PM
The KB tach feedback instructions cautioned that one has to observe correct polarity and if spindle reversal is used one has to devise a way to reverse the tach input polarity along with direction reversal. I started another thread about this and got several great ideas here on how to accomplish it but in the end decided to install a Mach controlled DPDT polarity reversing relay in series with the tach output that is triggered by a 5V relay hooked to the B.O.B. and pulled in only upon M4 (reverse) command.

A fellow on another forum educated me on proto boards, DIP sockets and 5V signal relays. Hard to believe I’m this old & never messed with that kind of stuff. I found the necessary parts at electronicgoldmine.com for a few bucks and proceeded to make a couple add-on boards to do the job. One board mounts inside the base enclosure and (a) sends a 12V signal to the DPDT relay on the other board in the speed control enclosure and (b) switches power on & off to the cutting oil pump. The bigger pump relay in the pic was snagged off an A/C control board they were throwing out at work. I love making stuff using free parts!

http://i57.photobucket.com/albums/g227/DBAviation/RelayBoardsFront_zps0cda8bb5.jpg (http://s57.photobucket.com/user/DBAviation/media/RelayBoardsFront_zps0cda8bb5.jpg.html)

Messy back side but hey, it works! Ya’ never know, there may be one other caveman out there (like me) that’s just been thawed out after 50 zillion years and has never worked with proto boards before. I think you’re supposed to just bridge between the copper pads with solder but I kept accidentally bridging over where I didn’t want so I switched to copper wires & that worked well for me.

http://i57.photobucket.com/albums/g227/DBAviation/RelayBoardsBack_zps6daaa3ec.jpg (http://s57.photobucket.com/user/DBAviation/media/RelayBoardsBack_zps6daaa3ec.jpg.html)

There was a short reverse polarity spike when stopping (M5) from a reverse (M4) command so I stuck in a couple diodes after the DPDT relay. That stopped the funny noise from the KB upon stopping after running the spindle in reverse.

http://i57.photobucket.com/albums/g227/DBAviation/RelayBoardTachReverse_zps26ec4c54.jpg (http://s57.photobucket.com/user/DBAviation/media/RelayBoardTachReverse_zps26ec4c54.jpg.html)

Here’s the oil pump I rigged up using a 12V auto sunroof blind motor (another freebie from work) and a Suzuki 125 2-stroke oil injection pump. I tried a 250 pump but it put out too much oil. The rate is easily adjustable using the rotary valve control that used to be connected to the throttle but all the way back to the idle position gives a steady drip – drip – drip that I ws looking for. Plenty good for keeping the work & tool wet but no so much that it makes a huge mess.

The 250 pump has 2 outlets & I may make another motor drive & relay control for it later to use it to lube the ways & ballscrews. This machine relies on the operator oiling it frequently so automatic oiling would be great.

http://i57.photobucket.com/albums/g227/DBAviation/PumpMounted_zpsa0bb1982.jpg (http://s57.photobucket.com/user/DBAviation/media/PumpMounted_zpsa0bb1982.jpg.html)

DICKEYBIRD
07-14-2013, 01:17 PM
Finished installation pic. The reservoir is a plastic1 pint brake fluid bottle. No need for a huge bottle with the slow drip-drip-drip feed.

http://i57.photobucket.com/albums/g227/DBAviation/OilerPump-Reservoir_zps47a95efa.jpg (http://s57.photobucket.com/user/DBAviation/media/OilerPump-Reservoir_zps47a95efa.jpg.html)

http://i57.photobucket.com/albums/g227/DBAviation/OilerNozzle_zpse67dde28.jpg (http://s57.photobucket.com/user/DBAviation/media/OilerNozzle_zpse67dde28.jpg.html)

I used Tygon tubing off ebay to plumb it as that stuff is very resistant to most oils and is pretty cheap. The flexible plastic nozzle is a brake cleaner straw and I used a mini DTI stand to position it. I stuck it on there temporarily to use it in various positions to see what I would need to make one but it works so well and it’s used so infrequently in its ‘real’ job it may end up living there from now on.

I’m real happy with how well the oiling system works as there’s no fumbling around looking for a squirt bottle and the nozzle can be placed right where it’s needed. The M8/M9 commands in Mach starts it dripping immediately and also stops instantly with maybe one solitary drip after it’s turned off. I’m not ready to make a new enclosure to support flood coolant so this method’s here to stay.

Threading test – FINALLY!

I decided the 1st test wouldn’t be on aluminum or acetal plastic because that doesn’t prove a thing, right?

I figured a 5/8” thread in steel would be a fair 1st test so out from the pile came a piece of cheap-o hardware store 5/8” CRS. Turns out I didn’t have a 5/8-18 nut or tap to trial fit the finished thread so said I hey, let’s do a 16x1.5 mm since I did have a die on hand in that size. Might as well see how well my inch machine does metrics! There’s probably a code I could have used to do metric without doing extra math but I didn’t feel like searching for it.

I quickly did the math to convert the major/minor dia’s from metric to inch & plugged those numbers into Mach’s Simple Threading wizard. I dialed in a .002” maximum depth of cut, with 4 spring passes, selected a thread length of ĺ”, posted the code, held my breath & clicked cycle start.

It started out great but was under obvious stress during the last 25 to 30% of the passes as the tool got deeper & deeper. I let it finish the code and the last spring pass was pretty clean. To my astonishment, the tap screwed right on with almost no slack. I think I teared up I was so jubilant. After looking more closely I could see tearing & ragged flanks on the threads so I decided to try again with a change to .001” D.O.C. That attempt was much better! I think it’ll do well when I get enough cash to get some decent threading inserts & a holder. All I had on hand was a cheap-o Enco brazed carbide tool.


http://i57.photobucket.com/albums/g227/DBAviation/ThreadTest_zps301aa278.jpg (http://s57.photobucket.com/user/DBAviation/media/ThreadTest_zps301aa278.jpg.html)

http://i57.photobucket.com/albums/g227/DBAviation/ThreadFin_zps611956f9.jpg (http://s57.photobucket.com/user/DBAviation/media/ThreadFin_zps611956f9.jpg.html)

The big crash came when I decided to part off the last thread test. Earlier in the day I had been parting off the 5/8” steel at 800 rpm & .75 IPM. With the cutting oil flowing right on the cut, it sliced right through like buttah with just a smooth swishing sound.

This time I typed G01X0F.75 in the MDI screen, hit return & waited to see the magic happen. BANG, the tool went straight into the work at high speed & stalled the spindle. I hit E-stop quick enough that no damage occurred.

After recovering everything, I decided I must have typed G00 by mistake and tried again. BANG, same thing! Another recovery, another insane attempt (insanity = doing the same thing over & over expecting different results) and BANG again. This time my laboriously hand-made-from-a-carbide-tablesaw-blade parting tool was destroyed.

You experienced CNC operators know what the problem was but I was convinced there just had to be a bug in Mach. A post over on the Mach support forum got me the answer from Hood immediately. (What would we do without him!)

Since threading requires feed per rev, there’s a G95 in the wizard’s code. G95 is modal so that leaves the machine in feed per rev mode. When I typed an F.75, Mach obediently gave me a .75 inch per *REV* feed rate. Yowzah, that’ll break your tool!

He suggested I do all my lathe programming in G95 inch per rev mode since that makes a lot more sense than inches per minute. I was still thinking in CNC router & mill terms since that’s where the majority of my meager CNC experience is. So, G95’s it shall be!

MaxHeadRoom
07-14-2013, 01:41 PM
A tip for the Proto boards is to use Strip Board, 3rd and 4th down, the traces are easy to jumper and break a trace using a small drill lightly to just break the foil.
http://www.futurlec.com/Protoboards.shtml
Max.

DICKEYBIRD
08-04-2013, 11:21 AM
I’ve been making a few parts with the ORAC lately and found that different cuts wanted more or less cutting oil. I could change the flow rate during the cut but had to walk around behind the machine & tweak the pump control arm. Pain in the behind!

Here’s what I came up with to make life a bit easier. The bellcrank & connector widgets were left over from my R/C model days. The rack & pinion remote cable/knob was given to me back in the 80’s. Dunno what it was made for but it works smooth as silk and was perfect for the job. Anybody else got packrat disease as bad as me?


http://i57.photobucket.com/albums/g227/DBAviation/OilerLinkage_zpse6b22206.jpg (http://s57.photobucket.com/user/DBAviation/media/OilerLinkage_zpse6b22206.jpg.html)


http://i57.photobucket.com/albums/g227/DBAviation/OilerLinkKnobDrive_zpsf2df3707.jpg (http://s57.photobucket.com/user/DBAviation/media/OilerLinkKnobDrive_zpsf2df3707.jpg.html)


I’ve been messing around with my Denford MicroMill lately(runs on Mach3 & W2000) and made a little label plate to go under the knob. The little thing does a pretty decent job! Gonna have to make up some more labels; that was fun!


http://i57.photobucket.com/albums/g227/DBAviation/OilerLabel_zps39bc6559.jpg (http://s57.photobucket.com/user/DBAviation/media/OilerLabel_zps39bc6559.jpg.html)

alastairseggie
09-12-2013, 09:32 AM
Hi Milton,

I have my Orac in Bits at the moment, I bought it in the summer but I have been getting a Bridgeport R2E3 Running, which is now completed. I am planning to start on the orac again. I am doing the prep for painting at the moment but the next thing will be the rebuild then the electrics. I am keen to get a few answers from those who have gone before me before I wander down the road of selecting parts.

I am in the UK, Scotland to be precise. We don't seem to have the same brand names or US prices. A good example is baldor. So I am going to have to understand the thought process you used and then apply that to what is available for a reasonable price on this side of the pond.

1) Stepper selection: What motors did you go for and why? Part numbers would be great so I can look at the DATA sheets.

2) I could not work out from your posts What voltage you decided to run the Steppers at. What did you eventually decide on?

3) Spindle drive: Why DC rather than 3ph AC with an VFD? Have you managed to set up your Instant reverse?

4) You went for 0.75 Hp but you have said (in your tool holder posts) that it was causing issues while threading because of a lack of power would you recommend going bigger than the 0.75?

Any help is most welcome.

Alastair.

DICKEYBIRD
09-12-2013, 07:13 PM
Hi Alastair; it’s good to hear from a fellow ORAC owner. I’ll do m’best to help.J

All of my decisions were made based on using the bits I had on hand or gave me the best “bang for the buck.”

A very kind forum member here on the forum sent me 2 Xylotex NEMA 23 stepper motors like these: http://www.xylotex.com/StepperMotor.htm They are 269 oz. in. 2.8A motors. I had an extra Smartstep3 controller from a Denford MicroMill. (Denford’s in sunny Brighouse W. Yorkshire…not too far from you !) The controller is only 2A@40V so the steppers aren’t fully powered and probably provide only 180-190 oz. in. of torque. That’s plenty of power for my use while learning since the crashes I’ve had ‘til now haven’t broken anything.

I chose the DC motor because I had several KB SCR DC speed controls on hand and wanted to use one of them. I was going to use a treadmill motor but decided to go with the Baldor because of its higher torque at low speeds. The treadmill motors run 4-5k and the Baldor runs 1750. DC motor/drives give excellent low speed power and I’m comfortable with setting them up. I didn’t want yet another software program (VFD) to scream at.

The DC motor itself has plenty of torque for threading but I tried to save myself some work by not making a 2-speed belt drive. The ratio I chose leans toward the top end since most of my work is under 1” in aluminum. I’m designing a reduction drive now and I’m pretty sure that’ll take care of the threading in steel problem.

Spindle reversing is working well now thanks to the more modern KBSI-240D controller I stole on ebay. Must admit I haven’t used reverse much yet but it’s there when I need it.

outback
09-16-2013, 06:50 AM
Hi Milton,
1) Stepper selection: What motors did you go for and why? Part numbers would be great so I can look at the DATA sheets.

2) I could not work out from your posts What voltage you decided to run the Steppers at. What did you eventually decide on?

3) Spindle drive: Why DC rather than 3ph AC with an VFD? Have you managed to set up your Instant reverse?

4) You went for 0.75 Hp but you have said (in your tool holder posts) that it was causing issues while threading because of a lack of power would you recommend going bigger than the 0.75?

Any help is most welcome.

Alastair.

Alastair; I also made a control for an Orac lathe. Milton told me about the lathe and where to buy it. It was on Ebay but I drove 250 miles to buy the lathe from the seller.

I was able to buy the original motor that came on the Orac. It is a 1/2 hp 3 phase motor. I found a variable frequency drive on Ebay and the VFD is controlled by the CNC control. Reverse and RPM is set manually. The motor that came on the lathe only runs about 1200 RPM. A motor with more RPM would be nice to have but doubt I'll change it. After all, it is an 8" lathe.

I used NEMA 23, Superior Electric stepper motors because they were given to me. I think they are 450 oz/in but they have plenty of speed and power. My power supply is around 45 VDC with plenty of amps. The current is limited at the Gecko driver boards to around 3 amps.

The breakout board was purchased from Bob Cambell designs. I like the breakout board. I never did setup my lathe
with limit switches.

The only problem I seem to have is maintaining a depth of cut. After a few passes my workpiece diameter increases
in size by a couple of thousandths kinda like tool wear. I can check the cross slide with a dial indicator and jog in and out a dozen times and the lathe repeats perfectly

I like the lathe itself. I would like to buy a manual version of the same 8"lathe.

Here is a link to my project: http://bbs.homeshopmachinist.net/threads/54027-Denford-Lathe-Retrofit?highlight=denford+orac
Jim

EVguru
09-16-2013, 07:37 AM
I like the lathe itself. I would like to buy a manual version of the same 8"lathe.


You should be able to find an Emco Compact 8. Many of the Chinese machines are copies of the Compact 8, some complete with all the design flaws. The following is taken from the entry on Tony's lathes.co.uk site;

Unfortunately, all was not as rosy as it first seemed for the lathe lacked a tumble-reverse mechanism - so making repeated boring operations and left-hand screwcutting difficult - only 6 changewheels were provided (though these were sufficient to provide a fine feed to the carriage) and there was no proper backgear, just a speed reduction through a toothed belt to a second pulley assembly. The omission of backgear was a considerable drawback for, with a bottom speed of 100 r.p.m., both screwcutting and the turning of large diameters was made more difficult for beginners.

alastairseggie
09-16-2013, 07:29 PM
(Denford’s in sunny Brighouse W. Yorkshire…not too far from you !)

Ive been to the Brighouse Factory twice and they guys there were very friendly, even let me have a few old control boards. I have over the years (since 2001) Owned 2 starmills, 2 Starturn 4's a starturn 8 and 2 oracs....the first Orac I restored as it was in very good condition to begin with. The latest one I got was just the lathe with all the electronics attached to the lathe frame nothing else, the chuck tool post and the tail stock which is in a bad way.

The KBSI-240D is just an isolator it is used in conjunction with the speed controller KBCC-125R with a 3/4 HP baldor is that right?

On this one I am planning to make a functional machine to give me the CNC functionality. I might try a new color scheme too!

Thanks for the Answers

Alastair.

alastairseggie
09-16-2013, 07:38 PM
Hi Jim

Yes I had read your thread too. which was why I wondered about the DC motor vs the 3ph on a vfd.


The only problem I seem to have is maintaining a depth of cut. After a few passes my workpiece diameter increases

What do you suppose this is backlash? Spring-Back on the tool? It should not be down to the stepper loosing steps as that would show as a step in the machining rather than a taper.

Alastair

DICKEYBIRD
09-16-2013, 11:41 PM
Ive been to the Brighouse Factory twice and they guys there were very friendly, even let me have a few old control boards.

The KBSI-240D is just an isolator it is used in conjunction with the speed controller KBCC-125R with a 3/4 HP baldor is that right?Brain fade...you're dead right! Got my numbers crossed up. I needed the signal isolator to fix a problem I was having early on getting the CNC4PC B.O.B's 0-10v analog speed control output to work with my 1st KBIC-120 speed control. The KBCC-125R came later when I added reversing. (Still had to have the isolator with it too.)

Yup, the Denford guys are great! Their forum is very helpful and one of the company admin's there sold me a used Smartstep3 for a very good price for a backup to the one in the MicroMill. I had cobbled up an add-on lathe attachment for it and found myself in a custom long-run job for a local company. About 300 pieces into an 1100 piece run I got really worried about the old thing dying with no replacement at hand and went looking.