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Hello Jeff,
Where do you purchase your white buna belts?
Dick
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http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION

Aaron,
The problems with the original Unimat universal motor are the facts that the motor runs at one speed and tends to want to race and they tend to run hot.
The 24 volt dc motor on the other hand is much more controllable, does not tend to race, get hot or need to rest to cool off.
Dick
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION

It seems like a motor that size defeats the point of a little lathe like a Unimat, being bigger than the lathe itself. I don't care for the size of the motor on my Taig, and am considering smaller alternatives.?

On a Unimat I'd think a small 1/12-1/15hp universal motor as you often find with watchmakers lathes would be a good choice. You can often find them for around $50 and they are suited to using a speed controller, like the HF one mentioned.?

My motor was playing up on my Unimat, so I fitted a 12v motor I had laying around that fit straight onto the bracket to get the lathe working again.
I then got a 12V 150w MY6812 scooter motor. All I had to do was add a hole on the front plate for an M5 nut and it fit onto the existing bracket.
A simple speed PWM controller was added and now I have a nice quiet Unimat. I 3D printed the pulley as I didn't want to modify the existing one.

I too have setup to use a 24v motor with power supply and speed controller, I turned a new end plate for the motor to fit it to the motor bracket and I also made a new 3 step pulley to fit on the larger shaft size it's all still in the making at the moment but it is looking good so far.

The motor was a NOS from a friend I had to replace the screws as when fitting the new end plate they came up short, and not been able to find out the rpm of the motor yet but will do soon.
Another small problem I have is the shaft is 11mm so when bored out of the pulley it does not leave much to lock onto the pin going through the motor shaft have to find another way to do it.

The controller I found on Amazon built it into a box and works well but it does not give out rpm only %.

Phill


?

I am using a 24v DC scooter motor with a power supply and speed controller on my DB200 lathe. Unbelievably quiet and smooth running.
Actually, I have two of these. The second motor is used on my vertical milling setup. If I recall correctly I paid about 25$ each for the motors on EBay a couple of years ago.
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION

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You can see them on the German ebay. They aren’t that much longer. I’m making a set of 36” specifically for tapering walking stick blanks for wood carving. Didn’t seem to make much sense to me to buy an inexpensive Chinese wood lathe that looks just as flimsy as the Unimat.

I am considering fashioning a set of extended way bars from 12mm linear rod, specifically to allow myself just a little bit of additional room for drill and tap operations. The $30 in stock from McMaster should do until I have space for a larger lathe. I have heard of the extended way bars for woodworking but have never seen them appear on eBay for sale.

On Wed, Jul 12, 2023 at 09:38 AM, John Hutnick wrote:

What is a positioner?? I do not quite understand how to control the speed for lathe use.? Turn it on and press buttons?

Positioner
These servo motors were originally designed for industrial sewing machines.? The positioner would be used to stop the motor with the needle in the raised position.? We don't care about the positioner, and I believe that the drive settings default to not having a positioner.

Speed control
On the sewing machine that these servos were designed for the speed control would be by the foot treadle.? The servo kit contains a Hall Effect sensor that is connected to that foot treadle by a lever arm.? This lever is spring loaded to return to a neutral position.? You can remove this spring and just use the lever to control the servo motor speed.? Once the lever leaves the neutral position and gets beyond the minimum speed point the servo will start running at the minimum speed setting.? Continuing to advance the lever arm will increase the speed of the motor until the motor speed eventually reaches the maximum speed setting.? This lever arm CAN be replaced with a speed pot, but it does require some electronics work to accomplish this - it's worth the effort though.?

Buttons
The buttons are used to change the motor direction, and/or modify the servo drive parameters.? These are CHEAP servo drives so there's not a lot of parameters that they let you play with.? The only parameters the I've changed in my servo drive were for the minimum speed, the maximum speed, and the brake.? My drive had what it called a brake effort parameter that defaulted to 1, the range was 0-5.? I set this to 0 and now my motor coasts when I change speed instead of braking.? If I've got the motor at speed, when I flip the Run/Stop switch to Stop the motor it will coast down to the minimum speed and then brake to a stop.? I haven't been able to figure out how to get it to coast to a stop, so I keep my minimum speed set at 100 Rpm.

Good deal?
A servo motor and a servo drive for $100-ish is a great deal.? Yeah it's Chinese, but what isn't anymore?

Is it the right motor for a Unimat?
MAAAYBEEE?? You can get sewing machine servo motors from 250W up to 750W.? The 750W is what I've got on my drill press.? I think you can probably even get a 1KW version of these servo motors.? Most of our Unimats started out their lives with U90 motors, or U100 motors if you were lucky, those were 90W and 100W motors.? Most of the DC scooter motor conversions were 150-250W motors.? Just because you've got the extra power doesn't mean you HAVE to use it.? That's one of the reasons the Uni has a belt drive, to keep it from hurting itself.? I mean it's not like we're putting a 3Hp motor on a Chinese mini-lathe is it?

Don

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Hi:

The positioner is a sensor that will stop the sewing machine with the needle in the up position.

Carl.

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I have one of these motors on my Taig lathe. They are very good and lots of torque and speed. One interesting wrinkle. With the default setting on ramp down time, the motor stops quite abruptly.