if you were to build a lathe, what would you do?

[gizmoid_52]

If you were to build a lathe what features would you include in it?
What spindle? d-1 loo threaded etc.
what spindle nose, morse or 5-c or?
how large a swing?
how long a bed
would you have incremental dials or Digital
readout?
what type bed, 2 vee? flat? or?
what about tailstock, what taper?
would you want a hollow spindle tailstock to
use long drills?
how much cross slide travel?
how about a longer compound for taper work?
would you have a seperate feed rod and lead
screw, and would the feed rod be ran by gears
from the headstock or DC driven?
Jack

[Thrud]

Well, for a 7"x18" I would build a Hardinge HLV series lathe loaded to the nuts. And I would have it painted Dupont's Chrome Allusions (the green and purple are cool) from the factory. That alone (the paint, man!) would most likey make the Hardinge Brothers rotate in their graves (my pardon if they are not dead yet).

Come to think of it, I would want the above in a 17"x48" with speeds to 6000RPM.

Dave (stop drooling on the HLV - no water based cutting fluids allowed!)Smith



[This message has been edited by Thrud (edited 10-30-2001).]

[halfnut]

I'll use this for expressing my Idea for a dream machine, one I could get a lot of use out of.

Spindle, D-1 series definately, spindle taper, #5 morse. Hole thru spindle doesn't have to be that big for my dream, handy lathe.

Swing, about 10", 6" tru adjust 3 jaw, 8" 4jaw, 5-C collet attachment with lever closer. Bed lenth, about 40" c to c, just so you can slide tailstock back out of the way further.

Bed needs to be nice and wide, about 12" for 10 swing, carriage also needs to be long, 14" should do it. Also the bed needs to be made so that the wings of the carriage will travel past the spindle nose, like they used to do it. 2 vees and 2 flats is good enough if the are of good size and of good material, high nickle iron.

With a 8" chuck I think the max. safe speed would be 3,000 rpm. A good 5hp motor would be enough, but the way they rate things today you would probably need a 7 1/2hp.

English, metric, diametrical, and modulus threading capabilities. A reversable leadscrew like a Hardinge or Hendey so you don't have to reverse spindle when cutting metrics, diametricals or moduluses.

A good long taper attachment of the compensating variety, 10 or 12 inches of travel. I like the one on my old Bradford about as well as any I have used, patent has probably ran out by now, it's a good design, the hendey design is good but I don't like the leadscrew handle going in and out.

I like a DRO, but it is hard to mount so that it isn't in the way. I still like a dial also, nice and big is better, satin chrome is great. At least a DRO for the carriage travel. Throw in a micrometer carriage stop also. But then again a travel dial set up is really nice, I can stop the carriage to a few thous with a travel dial, looking at those numbers on a DRO is not the same as watching a dial move. Analog is good. This is a dream machine, hang all of them on, what the heck.

Compounds, I don't cut that many long tapers with compound. With the bed built so that carriage wings go past spindle nose you don't need long compound.

Needs to be a clutch machine, forward reverse arrangement like a big Clausing. Nice for backing out taps.

Tailstock needs to be substantial, and it needs to be long so that when you are tapping and reaming with it it will slide easy without rocking. 200 thous per rev of handle, with a dial. I like this feature on new machines, you get used to this when running a bridgeport, 5 turns per inch, second nature after while. And about 5 1/2 inches of travel with a #4 morse taper, drive tang. Single lever clamping.

Foot brake with a nuetral return.

Scraped ways. Nice pretty frosting.

Balanced handwheels.

A feed gear diconnector and index marks for cutting multiple lead threads.

A cast iron headstock top that a mag base will stick to, dadburn aluminum things anyway. Tray top headstock and tailstock is good.

Flat tops on carriage wings for indicator use.

Separate cross slide and carriage feed clutches.

Supported leadscrew.

Dark green with gold pistriping would look nice.

I probrobably have left out something.

Price, who knows, this is a dream, right.

[jcurrell]

I have not found a perfact lathe yet that is why I have six from 5x12 to 26x78 each one has its uses and its good points. Start with what you are trying to do and grow as the need arises. Start making chips.

[gizmoid_52]

<font face="Verdana, Arial" size="2">Originally posted by halfnut:
I'll use this for expressing my Idea for a dream machine, one I could get a lot of use out of.

Spindle, D-1 series definately, spindle taper, #5 morse. Hole thru spindle doesn't have to be that big for my dream, handy lathe.

Swing, about 10", 6" tru adjust 3 jaw, 8" 4jaw, 5-C collet attachment with lever closer. Bed lenth, about 40" c to c, just so you can slide tailstock back out of the way further.

Bed needs to be nice and wide, about 12" for 10 swing, carriage also needs to be long, 14" should do it. Also the bed needs to be made so that the wings of the carriage will travel past the spindle nose, like they used to do it. 2 vees and 2 flats is good enough if the are of good size and of good material, high nickle iron.

With a 8" chuck I think the max. safe speed would be 3,000 rpm. A good 5hp motor would be enough, but the way they rate things today you would probably need a 7 1/2hp.

English, metric, diametrical, and modulus threading capabilities. A reversable leadscrew like a Hardinge or Hendey so you don't have to reverse spindle when cutting metrics, diametricals or moduluses.

A good long taper attachment of the compensating variety, 10 or 12 inches of travel. I like the one on my old Bradford about as well as any I have used, patent has probably ran out by now, it's a good design, the hendey design is good but I don't like the leadscrew handle going in and out.

I like a DRO, but it is hard to mount so that it isn't in the way. I still like a dial also, nice and big is better, satin chrome is great. At least a DRO for the carriage travel. Throw in a micrometer carriage stop also. But then again a travel dial set up is really nice, I can stop the carriage to a few thous with a travel dial, looking at those numbers on a DRO is not the same as watching a dial move. Analog is good. This is a dream machine, hang all of them on, what the heck.

Compounds, I don't cut that many long tapers with compound. With the bed built so that carriage wings go past spindle nose you don't need long compound.

Needs to be a clutch machine, forward reverse arrangement like a big Clausing. Nice for backing out taps.

Tailstock needs to be substantial, and it needs to be long so that when you are tapping and reaming with it it will slide easy without rocking. 200 thous per rev of handle, with a dial. I like this feature on new machines, you get used to this when running a bridgeport, 5 turns per inch, second nature after while. And about 5 1/2 inches of travel with a #4 morse taper, drive tang. Single lever clamping.

Foot brake with a nuetral return.

Scraped ways. Nice pretty frosting.

Balanced handwheels.

A feed gear diconnector and index marks for cutting multiple lead threads.

A cast iron headstock top that a mag base will stick to, dadburn aluminum things anyway. Tray top headstock and tailstock is good.

Flat tops on carriage wings for indicator use.

Separate cross slide and carriage feed clutches.

Supported leadscrew.

Dark green with gold pistriping would look nice.

I probrobably have left out something.

Price, who knows, this is a dream, right.

Good info, thanks this is what I want to hear
</font>

[halfnut]

Been thinking about bed dimensions, ratios and such. Even took a tape measure to 7 different lathes.

Widest and longest per swing was my Bradford, actual swing 19", width of bed 16 1/2", length of carriage 26". Good sturdy old machine, plenty of room for chips to get away.

Most ratio of carriage length to bed width was my Logan, actual swing 10", bed 7", and carriage 11" long.

So maybe I will revise my dream handy machine to 12" actual swing, bed width of 10 1/2 or 11 inches, and a carriage length of 15 to 16" long. It's a ratio thing.

Tailstock ratio should be I think about 1.25 longer than wide, and the front should protrude a bit like a Clausing tailstock. I like the clamping arrangement on my Hendey, rather a complicated affair, a series of levers and fulcrum points, with a single binding lever.

Also just for the fun of it, I think it needs the little reservoir on the tailstock for the dead center lube. Get a little retro.

Drive system would be easiest with a 2 or 3 speed gearbox and a vfd unit. Those things still scare me, I know they are good and cheap these days, but I have seen them Die like flies at work when they have a ground fault problem. I like the KISS rule, good old gears are hard to beat.

The top RPM problem, my 3,000 rpm is based upon a 8" chuck at 6,000 surface speed, I think that is maxinum safe speed with a cast iron chuck. You would have to ask Forrest on that one, he talked about it once.

Giz, I think I know who you are, you probably know my real name also. Forrest has the same wants as usual over at Chaski's, I think this subject was brought up once on D. Thomas's board, you might look at the past posts.

[Thrud]

Halfnut,

I have a 6 1/4" Forged steel 3 jaw with American pattern hardened topjaws safe to 4900 RPM. It sure holds stuff securely! I want high speed for the tiny stuff (so the center of the shaft is nice).

The problem with VFD's is most people just get the cheap stuff. An IGFET controller with all the bells & whistles and a HD 3Ph. specially wound motor to take full advantage of the controller is about $1000 (US) for a 2HP. (motor & controller).

Dave

[halfnut]

I work in a wood butchering plant in the toolroom. We have a lot of small high speed motors. They use a lot of rotary frequency converters, they are being phased out by the VFD units. I used to sit and BS with our electrical guru and wait till parking lot cleared. I'd listen to all the ills of this big saw or the machine who's parameters wouldn't reset, etc. One week I think they lost around a dozen VFD units.

The next week they chased ground faults, my poor thinker can't quite figure out how a short to ground would cause the voltage spikes they were getting. A digital meter wouldn't catch the spikes, our old electricians all use analog meter, they like to watch the needles move, or jump in this case. I got into the situation somewhat, had to chisel and drill out a heating element in a glue pot, that ceramic stuff is mean.

Our head electrical guru swears by these VFD units, that week I think the whole batch of electricians were swearing at them.

On the RPM problem, if only steel body chucks were used things would be good. But that dadburn Murphy and those laws he wrote. Someone would come along and put that old big cast iron chuck on that has that little crack from that crash 15 years ago and whiz it up in high gear.

Scary. I've heard the 6,000 sfpm deal as safe for a cast iron chuck in good condition. Was thinking about the largest chuck someone might put on machine and whether highest rpm was safe.

Machine not even built and product liability is limiting its posibilities.

The old bard of Avon was right, hang all Lawyers.

[Thrud]

Halfnut,

I have digital meters that "live" for those transients - electricians tend to buy cheap stuff because, well, they ARE electricians. I think they are scared of "new things".

I would not go by that 6ooo SFPM rule. Safer to check with the OEM and see what it can handle. I seen a forged steel flywheel cut a car in half when it blew at 6000 (okay, it might have had a LITTLE abuse behind that 429 SCJ Ram Air) - vroom, vroom, kaBOOM!

Dave

Maybe the smart tool technology used with some 50 taper machines (a chip that is read when the tool is changed that tells the computer the tool particulars) could be applied to chucks, telling the lathe, "Hey, I can only handle 2000 rpm", thus preventing stupid human tricks.


[This message has been edited by Thrud (edited 11-03-2001).]

[gizmoid_52]

You guys sound as "bad" as me, I have a bunch of lathes, mills, shapers, and etc.
someday when I go to the great machine shop
in the sky, I will think of my poor wife trying to sell all this old junk. Actually
I might smile, and maybe chuckle, and then
well we won't get into that.
I want to thank all of you who have contributed to this topic, I have read all your replys and of course want more!
One thing that has came up is VFD's I really appreciate the info, I will share my
ignorance, How can someone protect themselves
from the conditions halfnut speaks of? will a groundfault receptical as in a kitchen or bathroom, protect say a small VFD? would one want to say futher protect a VFD with surge protection? I am very interested in this topic.
One interesting point brought up on the Chaski BBS is a powered tailstock, I have always wanted a tailstock with a spindle hole
of around 1" , the reason behind this is gun
drilling or deep hole drilling could be accomplished without much problem.
The powered tailstock would definitely be a well added feature, especially if the tailstock could be set up like the carriage
is on the lathe, yet run on the inner ways.
It was suggested that it run somehow under
power from the headstock. I would not have any of the feeds governed by the headstock gears as this would require that the headstock be turning, to get the required feed. I would use a DC gear head controlled by a variable speed controller. I had to rebore my old 16" Southbend lathes headstock to install headstock bearings. The lathe was made during ww2 and had no bearings at all exept a special grade of nickle cast iron.
I set up a homemade powered line boring machine on my crossfeed slide, my lathe has
a english style cross slide, it has a tee slot completely across it. The boring bar I used was 1 1/2 chrome shafting. I used the rear bearing journal as a guide, and made a aluminum guide bushing to fit it. I also made a aluminum bushing for the front bearing journal, and used it just once to make sure the boring bar was in alignment.
Then I removed the front bushing and set up my cutter to take the first cut. My cutter was a square 3/8" brazed carbide cutter, turned round, I installed it in the bar by drilling a blind hole for the cutter
and drilled and tapped a hole in the opposite side of the cutter recess for an adjustment screw. I used a 3/8" setscrew to lock the cutter in place. I turned the boring bar with a 1/3 h.p. gear head motor
at 30 rpm. I powered the carriage with a DC
variable speed set up, hooked up to the lead screw. After boring the front journal, I simply removed the bushing in the rear journal, and made a bushing for the front journal and bored the rear journal. Once this was all done I turned out a set of bearing bronze split bushings like my little
10k has, and used some shim stock to provide future machinists a chance to take up a little wear.
Also was stated regarding the power tailstock, that the spindle could actually turn under power, the same speeds as the headstock. If this setup, was made and
the tailstock could run on ways like the carriage, then my job would have been very much simplified, I could have bored out my headstock without making a powered boring bar.
I would also power feed the carriage with
a DC motor, in both axis. The leadscrew would still be powered though the headstock however for threading. This way I could have an atachment which would do say, slotting work, or splines, or cut gears.
On my Southbend 10k lathe I have already drilled index holes around the perifiery of the chuck backplate, and made an indexing peg
set up to locate each position. On the ultimate lathe the headstock would be indexed but would also have a 40 tooth worm gear attachment with dividing plates so a much greater range of gears could be cut.
Also if I were building a lathe comercially
I would have Digital readouts on at least two axis. This would be a standard feature.
If I could pull it off the compound would have a worm gear to cut radi, and do spherical turning.
I like a machine as small and compact as possible, I would in that note give the lathe a large swing capacity, and provide a steady rest with 0-6" or more capacity, this
would make the lathe much more versitile in my opinion.

Your friend Jack.