Unimat DB/SL Replacement Motor
Best kept secret ?
As we all are aware, these machines are getting old. The original motors are wearing out, some beyond repair. The price for used motors on Ebay reflects this. Here again an old used motor.
Over the years, Unimat users have Emailed pix of their replacement motors. The range was from 1/2 HP 56 frame ( large ) AC motors to sewing machine motors. I say, that's great. This is a hobby machine and what ever works is fine.
For myself, I have modified about half dozen different motors, mostly Universal AC/ DC series wound. Like the original motors.
These high RPM motors ( 10,000 to 12,000 RPM ) were noisy and produce their torque at max speed, therefore any attempt to control ( reduce ) the motors speed is accompanied with a rapid decline in torque. I wanted something better.
About ten years ago I modified a commercial PMDC ( permanent magnet DC ) motor to accept the original pulley and mount up to the motor bracket using the original holes / screws. To drive the motor a complementary SCR ( DC )speed control package was developed.
The results were not unlike the Sherline lathe or even the 7" X 12" ' mini lathe ' , motor / control packages.
The motor package in the picture above has been in use for seven years ( the belt for nine years ).
The motor has ball bearings, long life brushes and rated for continuous duty. The SCR speed control produces almost pure DC
with form factor close to 1. Both are UL rated and made in the USA.
Speed control is mounted in aluminum box for heat dissipation has ON / OFF switch, internal replaceable fuse and four foot 120 volt AC cord / plug. Control box is mounted to motor. Input: 120 VAC 50/60 Hertz, 2 amps..
On balance, the objective was to provide a smooth, quite, long life, variable speed motor. Which was comparable in weight and dimensions with the OEM motor. PMDC motors by their very design are heaver motors
PMDC motors have the opposite torque curve of Universal AC/DC motors ( original Unimat motors ).
With a PMDC motor, as load is applied the torque increases and can be three to four times rated torque as stall is approached. Making it an excellent choice for this application.
Here are more pix of motor / controller mounted and in use.
Motor package spec: Motor rated 1/9 HP. 90 VDC. Speed control is adjusted for no load output of 700 to 3300 RPM. The machine above uses one large drive belt from middle motor pulley to middle spindle pulley gives spindle speed of 280 to 1300 RPM. Other belt / pulley configurations can be used .
This is a plug and play package. Motor shaft has pulley stop pin installed, ready to accept your motor pulley. Included are motor mount screws and pulley mount screw with washer. Speed control is pre-adjusted. These are assembled in my work shop, to order.
Price is SORRY NO LONGER AVAILABLE International email for shipping cost.
If interested please contact me via email to check availabilty or lead time and shipping cost.
Keep in mind. This package is best suited for turning / drilling / milling for precision work, in keeping with the original intent of the Unimat.
Giving you a powerful ( most torque of any replacement motor for the Unimat ), variable speed motor with smooth-quite operation. Making your DB/Sl more fun and comfortable to use.
Please have a look at these other pages of interest on my Unimat web site:
The motor and controller came in today. Runs like a dream. Thanks for all your help.
Hello Doug...!! Just a short note to advise you UNIMAT motor/speed control unit arrived Mon. ... WOW that was FAST...!!
You have made me the UNIMAT KING of Kansas City....!! VERY NICE package you have come up with....OUTSTANDING....!!
'Kansas City Ollie'
I received the Unimat replacement motor the workmanship and fit/finish look excellent, it'll be a great upgrade for my Unimat.
Thanks very much. Tom
( Tom bought two replacement motors, one for his lathe set-up and the other was a slightly smaller motor / controller package I made up for his mill set-up. Doug)
I bought one of your replacement motors a few weeks ago. Runs like a dream.
I have been asked. Why is the controller box as large as it is? Answer. The electronics fills up just about the whole box, also the aluminum box is the heat sink.
As an alternative, you can remove the control box from motor ( four screws ) and mount it on a pedestal, of your making, behind the lathe. There is 18" of cord between the two.
Got the motor and installed it. Works like a charm.
Funny, as an aside I had the old motor re-wound and it worked up to a point but it just didn't have the torque that the new motor has. The new motor definitely rocks!!
In a Word..........WoW! this motor gives a whole new meaning to the SL in 5 minutes, ( 4.75 installing) I knew I would have to completely re-evaluate what the Unimat will do, Won't do, I have not discovered
Thank you for a whole new world of fun for an old guy (82) Dick
your little motor has been working like a charm since last week. Thank you and let me wish you lots more business:
Fred lives in Switzerland. He has installed several 115 V outlets in his workshop, says American plugs are better..
The replacement motor is most excellent, thank you! Jeff
SORRY NO LONGER AVAILABLE
My guaranty; If not pleased with motor. Return as received. Refund less S/H.
Motor arrived and installed ( Rio de Janeiro! )
Doug: Thanks. Works smoothly. Speed control is a great feature. Sergio
Doug, I received the motor this afternoon and it is just what I expected it to be. It has been a pleasure dealing with you and I have your address if I need any further parts. Thank you, Hugh, CANADA
Got the motor last Friday. I've been so busy working with what amounts to a new lathe, that I almost forgot to thank you.
The new motor setup works great.
Thanks again, John
Motor comes with your choice of complementary belts..
Doug, Received motor on Monday. Looks and runs great. Thank you, Jerry
I would like to get another motor & controller rigs. love the first one I got.
Also would like a slow speed belt to go with it for my DB/SL. Jeff
Doug, Received and installed the motor Tuesday. Installation could not have been easier. Impressive low speed torque, and the free
set of belts were a bonus. Thank You, Paul
( Paul purchased two replacement motor / controller packages, one for his lathe set-up and the other for his mill set-up. )
Hi Doug, Motor very nice, lots of low speed power. Thanks , Thomas - Manhattan, NY
Thomas ordered motor/ controller for his SL 1000 lathe set-up. Liked it so much ordered another for his cast iron DB drilling / milling set-up.