Unimat SL lathe motor conversion.

[SmithDoor]

Hi Steamchick.

First, what can you say about long time (?) use of lathe with new motor.

Here is my take of Unimat motor.

View attachment 158259

View attachment 158260
It is a 200W spindle at 48V/12000RPM but at 24V it is just right at 6000RPM.
Pulley is custom made and is fixed between a shaft shoulder and chuck cap.
Heating is no problem.
It is speed controlled.
Some equivalent spindles are listed below:

Your choice of motor seems also smart -to me. I thought at it somehow; and even thought buying a a second hand cordless tool - 24V could offer such a motor and electronics at cheap. It seems they have the same motor as yours and can take enough abuse. And if their plastic housing can take the torque, for sure Unimat SL can take. Anyhow, the belts and their wise use limit both harmful torque on lathe and excesive heating on motor.

Looks nice

Dave

 

[Steamchick]

I managed a 2 hour spell, in 20 minute continuous sessions, without the motor overheating. I was turning a valve for a loco Safety Valve, from 5/16in. Hard brass to 0.079in shaft, 1 1/4in long, and 5/16in dia head. Cutting short , 1/4in, lengths at 0.2mm a time, to avoid distorting anything and losing precision.. Lots of passes, and swarf! Great fun! Felt the motor, warm, like a coffee cup, but not hot. Maybe 50 Dec C? Body exterior. I have atint computer fan blowing a whisper of air through the original motor body that holds the replacement motor. You can feel the exhaust is warm.... I should fit the fan inside the old housing to increase the draught.
The voltage control housing did not feel warm.
Must take a photo....
K2

 

[NapierDeltic]

Hi Steamchick.
Although I sometimes exagerate, usually appreciate wise, engineering use of resources. Your Unimat is not supposed to gather more than 20-40 hours continuous use each year. I consider your motor choice a good match and suited for portability (or storage). Please add second half of motor case or make a 3D printed one (it is a basic geometry with no big troubles ). I use to pay unwanted penalties for half finished jobs.

 

[Steamchick]

Hi Napier,
While my larger Chinese lathe is "without motor" - awaiting the new Servo-motor and variable speed drive system (from China!), I have used my Sl for less than 10 hours - this year. But will be doing some more work " maybe 5 hours?) making other parts that cannot wait for my bigger lathe.
Otherwise, I think I stay within 20 hours per year on it on average...
I do not have plastic printing capabilities, but can hack and file metal into most shapes... So at some time I will lose the gaffer tape holding the cooling fan, and install it inside the motor housing... (because I can, just short of inclination!).
Here's a picture I took - with chuck spinning!

- And an old photo of the motor fitting, and pulley drive I use.


The motor (compared to the original):

Checking today it is a "ARS-7912 DC 220-240V Class F 500W Motor 5mm Shaft 12800RPM - Home Appliances" = Cheap and cheerful! - I run it at 6000rpm max. = ~125W?
OK?
K2