Re: What is the Best Unimat ? and WHY !
Hi Phil, I'd love to see more pics of your setup, hi-res if possible, as I plan to do something very similar. Especially interested in the indexed divider, am thinking about the same for my vertical mill setup (I have 2 SLs). Are those steppers with a thru shaft? I've not seen them before, would be interested in where you sourced them.
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Emco Unimat 3 Lathe Attached To Wooden Box/ Accessories for auction on Goodwill site.
There ia a?Emco Unimat 3 Lathe Attached To Wooden Box/ Accessories for auction at the Goodwill site. The auction ends at??04/07/2023 07:46:00 PM PT. Richard B. 
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
I forgot to add I looked at adding plastic washers but guessed they might wear in time, I don't like the bent compression washers I think that would introduce some movement, I think by adding a hardened washer then the roller then a washer it has worked by far the best, cost a few ?'s or should I add $'s but that is it now I can go on and enjoy the lathe.
Phill
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Hi Dick, I never gave it a thought about making two like you have I just went looking at bearing supplies and found just what I was looking for, it has improved my little lathe 99% I don't have any problem with back lash on the screws and nut they are working really well.
?
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
On my 7x16 minilathe I made a small ball thrust bearing on the cross slide and was able to remove virtually all back lash on the cross slide of my minilathe. It was made from tiny loose balls in a circular groove. I see no reason this could not be adapted to the Unimat cross slide.
Dick
?
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Additionally it¡¯ll add friction to a point in the system where you really don¡¯t want additional friction.?
I find the best thing is to make a small washer out of a piece of plastic shim stock. ? That seems to smooth out the surface between the knob and the casting a little. ? I did that on my 3 in 1 mill which uses the same technology as the SL.?
But in the case of my Unimat, most of the backlash is the result of wear in the cross slide on both axis.? That would be more trouble to fix than it is worth.?
Hi:
The problem with the wave washer is, under a cutter load the side force will collapse the washer and the cutter path won't be straight.
Carl.
Perhaps using a curved, or wave, disk spring washer under the handle would give enough pre-load to minimize the backlash.
Something similar to one of these:
Richard B.
-- Quinn Golden
603-491-1451
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Hi Jeff:
The usual method is to take two motors apart and combine the stampings. I have used my Unimat to rewind a small can motor for one of my Lionel trains. I used my Erector set motor to turn the spindle slowly, a counter to keep track track of the windings. I made a holder on the face plate to hold the armature. The motor worked fine. Also counted the windings when I took the damaged wires off.
Carl.
On 04/06/2023 2:55 PM Jkle379184 via groups.io <jkle379184@...> wrote:
The hard part would be the layered sheet steel stampings for the armature. You need them for it to work instead machining a solid armature.
?Jeff
-----Original Message-----
From: Steve Johnson <steve@...>
To: [email protected]
Sent: Thu, Apr 6, 2023 12:24 pm
Subject: [Unimat] Electric Motors #db200
I've been musing about building a small electric motor from scratch on my Unimat SL.? Just for the fun of it and to learn something new. Seems like a doable project, including using the lathe to assist with the windings. Anyone on the list done anything like this?
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Hi:
The problem with the wave washer is, under a cutter load the side force will collapse the washer and the cutter path won't be straight.
Carl.
On 04/06/2023 1:01 PM Richard Burrows <bluerandonee@...> wrote:
Perhaps using a curved, or wave, disk spring washer under the handle would give enough pre-load to minimize the backlash.
Something similar to one of these:
https://www.mcmaster.com/9714k323/
Richard B.
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Hi Gang:
To improve the casting is just half of the job, you need to improve the runout on the knob. Both can be corrected with a file. Use some Persian Blue, coat the back of the know and run it up to the carriage. Look for where it rubs off the know and onto the carriage. File both spots down un till the Blue rubs off the whole knob and onto the whole casting. A bent lead screw will mess this up some, but it should help.
Carl.
On 04/06/2023 9:37 AM Quinn Golden <quinngolden@...> wrote:
When I rebuilt my SL, reducing the backlash as much as possible was a goal. However, there was a point of diminishing return as the hand wheel rubs against a rough uneven casting. With any flex in the screw train that gives a ¡°tight spot¡° as the hand wheel is rotated, exacerbating the problem. I tightened the hand wheel until it touched the casting, put on the nut and then tighten them together by hand, felt it then after a few tries gently tightened the nut. I had hit the ¡°sweet spot¡° that seems to work best. So short of machining that piece of casting behind the hand wheel to make it smoother, one needs to revert to the old primitive machining days of always moving your cutting tool into the work piece. Which is to say, you always back off a couple of turns on the handle and then go forward to remove the backlash and make your cut. ?I think that the casting is a poor enough bearing surface, so even placing thrust washers behind it would not illuminate the ¡°problem¡±. ?
That is to see if you consider it a problem, which I really do not. Anything that uses a lead screw into a tapped casting is going to have backlash. It is actually engineered that way.?
I have equipped my Unimat with dial indicators on both axis ?to enable me to see the backlash with every cut made.?
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The hard part would be the layered sheet steel stampings for the armature. You need them for it to work instead machining a solid armature.
?Jeff
-----Original Message-----
From: Steve Johnson <steve@...>
To: [email protected]
Sent: Thu, Apr 6, 2023 12:24 pm
Subject: [Unimat] Electric Motors #db200
I've been musing about building a small electric motor from scratch on my Unimat SL.? Just for the fun of it and to learn something new. Seems like a doable project, including using the lathe to assist with the windings. Anyone on the list done anything like this?
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Re: Unimat black crackle jig-saw
Hammertone paint used to be considered a very rugged industrial coating that was also oil and solvent resistant.
?Jeff
-----Original Message-----
From: g steinback via groups.io <Gsteinba52@...>
To: [email protected] < [email protected]>; alan.ehrlich@... <alan.ehrlich@...>
Sent: Thu, Apr 6, 2023 12:53 pm
Subject: Re: [Unimat] Unimat black crackle jig-saw
Thanks Alan, I stand corrected (I'm in the US.)
Personally I would have preferred a machine gray finish on my DB200 (maybe if I ever have to repaint it) and wonder why the hammertone silver/green was used. There was a note on one of the product descriptions suggesting that hammertone paint 'hid' slight surface imperfections better than a flat paint - even though the Unimat castings seem very well done.
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Just to confirm, what is this cross slide nut material?
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Perhaps using a curved, or wave, disk spring washer under the handle would give enough pre-load to minimize the backlash. Something similar to one of these:
https://www.mcmaster.com/9714k323/
Richard B.
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Re: Unimat black crackle jig-saw
Thanks Alan, I stand corrected (I'm in the US.)
Personally I would have preferred a machine gray finish on my DB200 (maybe if I ever have to repaint it) and wonder why the hammertone silver/green was used. There was a note on one of the product descriptions suggesting that hammertone paint 'hid' slight surface imperfections better than a flat paint - even though the Unimat castings seem very well done.
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Thanks for that link! I have ordered everything I need to make my own collet holder - sounds like a fun project! And - the threading technique in the procedure is just genius. Thinking of making a kit with varying thread pitches using this idea.
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Incidentally I have installed a new lead screw when I rebuilt the lathe. ?So my backlash is in the cross slide. ?
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I've been musing about building a small electric motor from scratch on my Unimat SL.? Just for the fun of it and to learn something new. Seems like a doable project, including using the lathe to assist with the windings. Anyone on the list done anything like this?
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
So on the SL the cross slide does not have a ¡°nut¡° in it. The Cross light itself is threaded to match the lead screw. So adjusting for wear is hopeless unless one can find a good as new cross slide.?
As for your idea to modify the nut, it is valid. The attached photo shows the method to take up the slack in the tag system. ?
On Thu, Apr 6, 2023 at 12:17 PM jpow < powster@...> wrote: Thank you everyone for the advice / knowledge sharing! I've realised that for my case, backlash is from both handle assembly (maybe 30% of the backlash) AND cross slide nut (majority of the backlash)? While I accept some backlash will?always be there, I can't help but think of other possible?ways to minimize it. Might this idea be feasible: The cross slide nut is approx 10mm x10mm x 10mm cube.? Is there enough material to modify?the nut into an anti-backlash design, i.e. a) Cut a slit through the nut b) Tap a tiny thread for a screw to finely adjust the size of the slit gap (so as to apply pressure on the threads, minimizing play)
Alternatively, replace the entire nut with some anti-backlash design. The only thing is that its going to be a pain to adjust it, as my UNIMAT PC doesn't leave much room to access that nut with the slide assembled fully.
@Quinn
- One option might be to just replace the cross slide nut, and / or the entire leadscrew, ASSUMING the backlash is due to heavy wear on the threads. - Arceurotrade has a that looks like it could fit with some minor modification.
Yeah that completely makes sense, I have a Taig CNC machine that uses the same technology as a Unimat, and I program the backlash compensation into it.? When it reads the code it compensates for backlash due to its design. ? ?
What were the part numbers of the thrust washers that you settled on ??
I wound up settling on about .0035 backlash on the Y(cross slide) and .0025 on the X.?
However in my case I am convinced that the backlash on the cross slide is in the Cross slide itself and not the handle. ? ?
I¡¯m not sure buying another used one would make it any better, I might buy another ¡°new old stock¡± if I can find it. ?
On Thu, Apr 6, 2023 at 02:37 PM, Quinn Golden wrote:
you always back off a couple of turns on the handle and then go forward to remove the backlash and make your cut.
This is what I was taught to do and have done on all my larger lathes, but on the small SL it was a problem that needed more looking at if I was to use power on the screws, my first thought was I could not get the backlash down to an acceptable level because the cast was a little rough and the aluminium hand wheel was dragging and wearing off creating more backlash, I could have turned some hard plastic washers but having used very small bearings in other work I opted to use the small thrust bearings and I found I could get a really good feel turning by hand and under power it works so well for me.
With a wipe of grease on assembly these fit well, feel well and one less thing to worry about when machining.
 ??
Phill
Quinn Golden
603-491-1451
-- Quinn Golden
603-491-1451
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Seems like a common plan. I was buying parts for my recently acquired SL, and suddenly realized I had almost enough parts for a second unit, which I will use as a mill. Adding a DC motor and speed controller, and beginning to think through the process of making the mill both manual and CNC capable.
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Re: Unimat 3 / PC Cross Slide Backlash from HANDLEWHEEL
Thank you everyone for the advice / knowledge sharing! I've realised that for my case, backlash is from both handle assembly (maybe 30% of the backlash) AND cross slide nut (majority of the backlash)? While I accept some backlash will?always be there, I can't help but think of other possible?ways to minimize it. Might this idea be feasible: The cross slide nut is approx 10mm x10mm x 10mm cube.? Is there enough material to modify?the nut into an anti-backlash design, i.e. a) Cut a slit through the nut b) Tap a tiny thread for a screw to finely adjust the size of the slit gap (so as to apply pressure on the threads, minimizing play)
Alternatively, replace the entire nut with some anti-backlash design. The only thing is that its going to be a pain to adjust it, as my UNIMAT PC doesn't leave much room to access that nut with the slide assembled fully.
@Quinn
- One option might be to just replace the cross slide nut, and / or the entire leadscrew, ASSUMING the backlash is due to heavy wear on the threads. - Arceurotrade has a that looks like it could fit with some minor modification.
Yeah that completely makes sense, I have a Taig CNC machine that uses the same technology as a Unimat, and I program the backlash compensation into it.? When it reads the code it compensates for backlash due to its design. ? ?
What were the part numbers of the thrust washers that you settled on ??
I wound up settling on about .0035 backlash on the Y(cross slide) and .0025 on the X.?
However in my case I am convinced that the backlash on the cross slide is in the Cross slide itself and not the handle. ? ?
I¡¯m not sure buying another used one would make it any better, I might buy another ¡°new old stock¡± if I can find it. ?
On Thu, Apr 6, 2023 at 02:37 PM, Quinn Golden wrote:
you always back off a couple of turns on the handle and then go forward to remove the backlash and make your cut.
This is what I was taught to do and have done on all my larger lathes, but on the small SL it was a problem that needed more looking at if I was to use power on the screws, my first thought was I could not get the backlash down to an acceptable level because the cast was a little rough and the aluminium hand wheel was dragging and wearing off creating more backlash, I could have turned some hard plastic washers but having used very small bearings in other work I opted to use the small thrust bearings and I found I could get a really good feel turning by hand and under power it works so well for me.
With a wipe of grease on assembly these fit well, feel well and one less thing to worry about when machining.
 ??
Phill
Quinn Golden
603-491-1451
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Steve Johnson
OldToolmaker
Carl