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torker
12-20-2006, 03:31 PM
Hey all! This one has always bugged me. It wasn't too bad on my SB9 as the chuck had pretty small jaws etc.
I'm making a few micrometer dials for my T+C grinder and am baffled how to turn the thin plates.
How would you turn and face a 3/16" thickX 3 1/2" plate dia plate....with no center hole?
Or (say) a 1/4" plateX4" dia with a 1/8" hole...can't use an arbor for that small.
I've made up several arbors for this but the holes have to be the bigger size to get the center bolt clamping force to hold it still for turning.
I should be able to figure this one out but this "night shift" fog (about 4 months now)has me a bit dozey.
I know I can weld a shaft to the plate but I don't like the hard spots it created. Someone at work suggested cutting or grinding a small step in the ends of the chuck jaws to hold 1/8" or so. I no likey that one for my new chucks.
I have plenty of bearing race outers to use as spacers but they are seldom the right size.
Thanks!
Russ
*** Tried to edit Thread Subject Name...hahahaha...said truning....wonder what that is>

Your Old Dog
12-20-2006, 03:45 PM
Can it be epoxied to a plate that you can weld to? 5 minute epoxy over an alcholo cleaned surface is pretty remarkable. I little burnz-o-matic heat should release it.

jkilroy
12-20-2006, 03:45 PM
I would like to add, how about turning largeish thin plates, say 8" OD 1 inch thick plates of aluminum. I need to face both sides, drill AND cut a 3/8's groove in the center of the OD. That 3/8's thing leaves me with 5/8's stock, equally divided into nice 5/16's pieces to chuck to. Can you hold a 8" piece of stock on 1/4" firmly enough to cut a 1/2 deep groove in the OD? So far I have done this as a faceplate job and it works, just looking for possible ways to save time.

Rusty Marlin
12-20-2006, 04:11 PM
Time to buy a Blanchard grinder.

What do the plates start out as? Band sawn slugs from round or treepan cut from plate?

Evan
12-20-2006, 04:25 PM
Russ,

Cut the piece from a chunk of bar or plate thicker than the finished product. Chuck it up, center doesn't matter. Now face off one side but leave about 3/16 by 3/16 of a lip that will allow for holding the plate from that side from the inside. Then flip it over and you can hold on the inside, face the other side and true circumference. Then flip again and you have nearly the full thickness of the plate to hold on to by the outside to turn off the lip.

BadDog
12-20-2006, 04:32 PM
Soft jaws?

Tin Falcon
12-20-2006, 04:59 PM
Russ you did not say what material .Here is what I did to get 4 1/2 inch circles in 1/8 plate Aluminum no hole and 3/16 hole put a center mark on your blank and lay out your circle with dividers or a compass with fine line sharpy. then a couple options rough cut on the band saw and turn it to size. Or right to the lathe and trepan. I trepaned out a couple of 4 1/2" blanks a couple of weeks ago on the south bend. I put a rubber pad between the piece and the face plate. also double sided tape works just push the live center into the center punched mark set the handle on the tail stock so gravity and vibration will tighten it and not loosten it. If you take to heavy a cut it may slip. Be a little cautious. I have not hurt myself or anthing else with this technique. Use a little kero or your favorite aluminum cutting fluid. BTW trepaning is kind of like using a cut off tool sideways.You may want to move the tool back and forth a little (in between cuts)and not just take one plung cut. I use an 1/8 tool bit ground 1/16 wide set in a piece of 3/8 mild steel with a 1/8 slot milled into it. I have one milled with built in back rake and one straight.
I do not know the alloy I cut probly 6061 it was off the shelf at the surplus yard. I do know it cut nice so not likely 3003.
Hope this helps. BTW this was what I posted on the 4" hole saw thread.
Tin

ptjw7uk
12-20-2006, 06:26 PM
If you are making them out of thin sheet, put a slug of metal with a diameter just less than the finished item. Sling it in the chuck and face off to a good finish, degrease surface then stick your bandsaw cut blank to the faced surface using double sided tape (I have an old supply of 3" wide strip) press hard and machine using small cuts, you will be surprised how tough that double sided tape is. You will find this out when you try to remove the disk( soak in hot water)

I also use the tape to stick fresh sanding sheets to my disk sander.

Peter

Mcgyver
12-20-2006, 07:17 PM
Russ, these work well

http://images.google.com/imgres?imgurl=http://www.royalprod.com/img/category/upload/chuckstops3.jpg&imgrefurl=http://www.royalprod.com/product.cfm%3FcatID%3D12&h=322&w=268&sz=11&hl=en&start=1&tbnid=Tkm9kSJztV5n9M:&tbnh=118&tbnw=98&prev=/images%3Fq%3Droyal%2Bchuck%2Bstops%26svnum%3D10%26 hl%3Den%26lr%3D%26rls%3DGGLG,GGLG:2005-23,GGLG:en%26sa%3DN

kbc sells them at stupid prices, I just made my own, either mill three slots out an appropriately thick disk, or weld, stress relieve and grind out of steel, like asterisk shape but only three points.

I've cut the periphery of thin disks, like down to sheet metal thick, by stick it with double sided tape to something held and the chuck applying pressure by the tail stock using a disk flat on one side and with a centre drilled hole on the other. not much of a production technique, but it works. to machine all over, hold in three jaw face, flip and face other side...with a good chuck stop they are now parallel (if you need it more so, its off to the grinder) then do the periphery between the two bungs.

nheng
12-20-2006, 08:40 PM
Torker, You mentioned the smaller SB so if your new machine can take a 5C collet, you can use a 5C pot chuck. Machine a disk out of the face of the pot chuck, a few thou over the diameter of your round stock. Oh yeah, you'd have to start with round stock.

Using a chuck, a quick and easy way to get a "shallow" grip on thin disks is to use a tailstock pad, a flat disk of several inch diameter or so and mating taper for your tailstock. You machine the disk to be square to the axis of the taper end. The face of the pad can then be set against either a fresh disk or one turned face of a disk and then adjust for the length of the grip you want before tightening the chuck. I've done a number of 6" disks, 3/8" thick, out of 6061 by setting them up this way.

The tailstock pad can also have a vee cut across its face in order to center round stock for spindle mounted drilling of odd parts.

Alternately, you could simply put spacers between the disk and the lathe jaws but I find this method quicker.

Either method can be used for OD but the part has to be flipped to finish. The 5C pot chuck can be machined with two bores, one deeper and to the finished OD, the outer to the raw OD. You turn half of the length, flip and regrip in the 2nd, smaller bore, and finish the length, blending as necessary. Den

madman
12-20-2006, 09:02 PM
Torker hows about taking a flat bar that will encompose thw diameter of your chuck. (in other woirds reach from one jaw to another lengthwise) then one magnet at each end of the bar. Now you need to have a smallish shim (washers) under the magnet equipped piece of steel so it will stick to the jaw face through magnetism also it will hold your steel (?) piece at the correct distance from your chuck jaws with only the small amount overhanging the jaws that is equivalent to the washer thickness washer shim material you placed behind the magnetized flat bar sitting against the face of the jaws of your chuck with the workpiece stuck behind it also held in place by the magnets affixed to the front of the steel piece spanning the face of the chuck jaws . **** what a mouthfull and im drunk too boot, Do you understand what im trying to convey? Please let me know if not and ill try again all i know is ive done stuff like this many times and it alweays works out. Good Luck Mike aka madman BUURP

BadDog
12-21-2006, 12:35 AM
Using a chuck, a quick and easy way to get a "shallow" grip on thin disks is to use a tailstock pad, a flat disk of several inch diameter or so and mating taper for your tailstock. You machine the disk to be square to the axis of the taper end. The face of the pad can then be set against either a fresh disk or one turned face of a disk and then adjust for the length of the grip you want before tightening the chuck. I've done a number of 6" disks, 3/8" thick, out of 6061 by setting them up this way.

The tailstock pad can also have a vee cut across its face in order to center round stock for spindle mounted drilling of odd parts.

Aha! So that's what those tailstock pads are used for! :D I've heard them called "drill pads" and such, but never saw a use for them...

JRouche
12-21-2006, 02:57 AM
I have turned 1/4"x 6" discs by bandsawing the disc to oversize and welding (tacking) the disc to a section of pipe. I chuck the pipe up and turn the OD of the disc. Stainless is what I was turning. These were end caps to a largeish roller. The tacked side was cleaned up with an abrasive disc...JRouche

Spin Doctor
12-21-2006, 10:36 AM
At work I cheated and used one of these on a Hardinge. Light cuts and tap it around to make sure it is centerd up

http://img.photobucket.com/albums/v19/markandannie/Tips/0854006-11.jpg

torker
12-21-2006, 01:38 PM
Thanks guys! Some cool ideas!
Umm...Spin, what the heck is that thing? A magnetic chuck?
Russ

Spin Doctor
12-21-2006, 05:21 PM
Thanks guys! Some cool ideas!
Umm...Spin, what the heck is that thing? A magnetic chuck?
Russ

Give the man a cigar. As long as the part being held is flat and large enough (a 1/2" washer is far too small they work quite well actually. A bit pricy for the home shop but if I stumbled across one on ebay for cheap I think I'd grab it. The one I used to use sat on the shelf for a couple of years beacuse nobody could figure out what it was for (the boss that ordered it retired before it came in). I figured, what the heck, we've got a Hardinge 4D spindle nose adaptor just sitting in the cabinet and put it together.