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Would it be feasible to adapt the Uni 3 threading attachment to the Unimat DB 200?
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Not really. It would make far more sense to sell it and buy the correct attachment.
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Having both a U3 and an SL, each with it's appropriate threading accessory, I absolutely agree with Matt. In fact, it would be simpler to build an attachment from scratch than to try to adapt the ¡¯wrong one¡¯ to your machine.
I¡¯d recommend you sell the U3 attachment and buy the correct one for the DB200... Or else sell the DB200 lathe itself and replace it with a U3 ?
Friendly regards
Alan
Geneva, Switzerland
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There used to be a weird system that kind of did that but it was a big box that sat under the lathe and only did a few threads.
Not sure where you'll find info - check the Links section which is called Databases?here.
On Thu, Mar 2, 2023 at 2:34?PM OldToolmaker via <old_toolmaker= [email protected]> wrote: Would it be feasible to adapt the Uni 3 threading attachment to the Unimat DB 200?
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On Fri, Mar 3, 2023 at 03:45 AM, Neil Morrison wrote:
There used to be a weird system that kind of did that but it was a big box that sat under the lathe and only did a few threads.
Look for? CarlcoPatent4171649.pdf in the Files section. Much discussed long ago. It represents the only practical way to add a threading and feeds box to the DB/SL, but I reckon anyone doing it now could do it better. For a start a decent range of gears is (effectively) much cheaper now than they used to be and working methods to get them to mesh nicely are better too. However the gearing needed to get a 27 tpi thread using a 1 mm pitch lead screw are complex even with clever use of 17 tooth gears, as on the SL, or with 19 tooth gears as I have seen on other lathes using an inch lead screw to get metric threads - and even more cunning to generate ¦Ð to turn worms in both DP and Mod pitches. On a very good day I can understand it. Not that good a day today.
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Actually, looking at it again I find that a simple ratio of 16:17 from the chuck to the leadscrew will give a pitch of 26.9875 tpi -probably good enough for what I suspect is a short collar. However the problem is to make that connection between the spindle and the leadscrew. It can be done, and might be worth the effort if you had a lot of them to do, and couldn't buy a tap for less than $30.
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Hello Keith,
I also think it is possible to couple the lead screw to the spindle through a set of change gears to obtain various thread leads. It could be an interesting design exercise but not very practical for me as I have a 7X 16 lathe for this sort of work.
Dick
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There's another group on :?E-Leadscrew
That should be cheaper and better.
"ELS" - Electronic Lead Screw ¡ª is an alternative to full CNC for simple bench lathes ¡ª especially those lathes which do not have a "Quick Change Gear Box". For such lathes, it would be useful to have a cheap method of sychronizing spindle speed to lead screw speed. If this can be realized electronically, then all threading can be done without the necessity of changing manual gears. Also, all saddle traverse speed ratios become possible.
The aim of this group is to develop a simple, cost-effective electronic and mechanical system for implementing ELS - which in theory would be cheaper than CNC, and which can be ported to hobby-class bench lathes.
Member John Dammeyer has led the way in these discussions. He has designed a system, which is described in a comprehensive article "Electronics Gear Control" in the magazine "Circuit Celler" ¡ª Nov/2006, Issue 196, pp 36-43.
On Sun, Mar 5, 2023 at 6:26?AM OldToolmaker via <old_toolmaker= [email protected]> wrote: Hello Keith,
I also think it is possible to couple the lead screw to the spindle through a set of change gears to obtain various thread leads. It could be an interesting design exercise but not very practical for me as I have a 7X 16 lathe for this sort of work.
Dick
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I recently bought one of his ELS units, fully assembled and tested, $150+ shipping from Canada. Not planning on putting it on my Unimats, though. Going to put it on the Smithy CB-1220XL my brother insisted I need. I think it's a hint he wants me to make stuff for him. ;)
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Sunday, March 5, 2023 at 01:38:54 PM CST, Neil Morrison <neilsmorr@...> wrote:
There's another group on :?E-Leadscrew
That should be cheaper and better.
"ELS" - Electronic Lead Screw ¡ª is an alternative to full CNC for simple bench lathes ¡ª especially those lathes which do not have a "Quick Change Gear Box". For such lathes, it would be useful to have a cheap method of sychronizing spindle speed to lead screw speed. If this can be realized electronically, then all threading can be done without the necessity of changing manual gears. Also, all saddle traverse speed ratios become possible.
The aim of this group is to develop a simple, cost-effective electronic and mechanical system for implementing ELS - which in theory would be cheaper than CNC, and which can be ported to hobby-class bench lathes.
Member John Dammeyer has led the way in these discussions. He has designed a system, which is described in a comprehensive article "Electronics Gear Control" in the magazine "Circuit Celler" ¡ª Nov/2006, Issue 196, pp 36-43.
On Sun, Mar 5, 2023 at 6:26?AM OldToolmaker via <old_toolmaker= [email protected]> wrote: Hello Keith,
I also think it is possible to couple the lead screw to the spindle through a set of change gears to obtain various thread leads. It could be an interesting design exercise but not very practical for me as I have a 7X 16 lathe for this sort of work.
Dick
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The Carlco unit was fitted under the base, below the headstock with a toothed belt drive from the spindle, then the output shaft was on the centre line under the base, with a second toothed belt up to the saddle feed handle. As I see it all practical solutions are going to be similar, with the variables being:
Gearbox under the base, in front, or behind.
Gearbox at the head or tailstock end
The number of thread pitches accommodated as a quick change device.
In my opinion, first design the gearbox. As an alternative to the ELS system, I did read (somewhere) of an electronic gearbox. The input shaft drove an encoder, and the output shaft was driven by a motor. In between was a processor of some sort making the output bear some relation to the input. It's easy to imagine a stepper motor doing the output, and a microprocessor doing the arithmetic. The limits to performance are the speed of the microprocessor to keep up with the rate of calculations EG with the spindle running at 6000 rpm, and the torque of the output motor to drive the output with sufficient force to overcome any likely loads. The user interface might be a headache if it is a stand alone unit.
It would also be practical to have the encoder at one end, and the motor at the other end of the lathe.
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John Dammeyer's ELS will do that. He's installed them on his Gingery Lathes and a SB Heavy 10L. Somebody has put one on a Unimat, as well. Uses a 1ppr encoder to track spindle speed, since those were doable without spending the world on an encoder. Newer encoders have come down a lot in price since then, but his system was designed for spindle speed up to 6000RPM.
Bill in OKC?
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Sunday, March 5, 2023 at 09:03:17 PM CST, Keith S. Angus <keithsangus@...> wrote:
The Carlco unit was fitted under the base, below the headstock with a toothed belt drive from the spindle, then the output shaft was on the centre line under the base, with a second toothed belt up to the saddle feed handle. As I see it all practical solutions are going to be similar, with the variables being:
Gearbox under the base, in front, or behind.
Gearbox at the head or tailstock end
The number of thread pitches accommodated as a quick change device.
In my opinion, first design the gearbox. As an alternative to the ELS system, I did read (somewhere) of an electronic gearbox. The input shaft drove an encoder, and the output shaft was driven by a motor. In between was a processor of some sort making the output bear some relation to the input. It's easy to imagine a stepper motor doing the output, and a microprocessor doing the arithmetic. The limits to performance are the speed of the microprocessor to keep up with the rate of calculations EG with the spindle running at 6000 rpm, and the torque of the output motor to drive the output with sufficient force to overcome any likely loads. The user interface might be a headache if it is a stand alone unit.
It would also be practical to have the encoder at one end, and the motor at the other end of the lathe.
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Hello Bill,
I prefer the simplicity of a mechanical system over a digital one, although they each have pluses and minuses. To each his own I guess.
Dick
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I'm getting ready to make one of John Wilding's clocks, which will need a 290 tooth great wheel. I'm expecting to create some kind of digital dividing head for that, because I don't think 290 is a common gear size! Certainly not on Unimats(though I guess it's unlikely I can fit the 9 inch blank on the Unimat SL anyway).
Jeff
Hello Bill,
I prefer the simplicity of a mechanical system over a digital one, although they each have pluses and minuses. To each his own I guess.
Dick
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I actually agree with you on this. But I can see uses for the digital systems too. And I want to learn more about both. I wound up with a spare machine that cost me nothing but a little time. It's the one that is going digital, since it's a bit lacking in charm. I have to do something with it, and the ELS will let me turn it loose on fairly simple projects like tapers and threading without constant supervision, while I do something else. Not much artistry involved,but good for a bit of production. If I do some of the things I want to do, I'll need some unusual hardware and the ELS will help me get it.
And let we spend most of my effort on other things. :)
Bill in OKC?
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Monday, March 6, 2023 at 10:15:42 AM CST, OldToolmaker via groups.io <old_toolmaker@...> wrote:
Hello Bill,
I prefer the simplicity of a mechanical system over a digital one, although they each have pluses and minuses. To each his own I guess.
Dick
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On Sun, Mar 5, 2023 at 06:26 AM, OldToolmaker wrote:
Hello Keith,
I also think it is possible to couple the lead screw to the spindle through a set of change gears to obtain various thread leads. It could be an interesting design exercise but not very practical for me as I have a 7X 16 lathe for this sort of work.
Dick
Something like this would work, with minilathe change gears, too, just with a fixed drive shaft under or behind the bed instead of the telescoping one - a stepper based threading attachment might be simpler and lose less power, though. 
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OldToolmaker
Unimat Matt
Bill in OKC too
