24V DC Motor for the Unimat

24V DC Motor for the Unimat 3 designed, made and authored by Ray Dean, Sydney.

I thought you might be interested in this story about my little Unimat 3. I needed a new motor for Unimat 3 where I had fitted a sewing machine motor in place of the original which had blown when I borrowed it from a friend. It had only ever been used to skim roller skate wheels and had a mandrel rather than a chuck.

As it turned out, the 90W motor I fitted was only about 40% efficient and was basically gutless. I got the machine back again after he passed away in 2019 and had thought of fitting a 180W sewing machine motor.

Anyway, I never attempted that but over the last couple of months and a lot of research, have built it up successfully as follows….

24V DC Drive

I have fitted a new drive consisting of 24V DC, 775 high torque 150W, ~7500RPM motor, a 24V, 10A power supply and a reversible speed controller.

Also added are a brand new SAN AU 63mm chuck, a 10mm drill chuck and have a live centre in the mail.

So far I have experimented a little but not made anything yet but it seems work very well. Much better than the sewing machine motor and the original drive as well, with plenty of torque, much more, probably 3x that of the sewing machine motor. I have run the machine in high and low range ie with the original main shaft double pulley driven by the sewing machine pulley via a silicon O-ring.

I have clocked the speeds with a tachometer and have from 50rpm to 2900rpm depending on which pulley combination. By changing the small drive pulley to one about 30mm dia, it would run at 4000 rpm.

The drive parts cost me in Australian Dollars about $80 which would be around £50 but that would also depend on supplier and postage.

The drawing is a bit busy but I was OK using it.

There are other motors for the Unimat 3, but this is probably one of the most practical and best. These drawings should enable anyone to take on this conversion to 24V DC Motor for the Unimat 3. A big thanks to Ray for sharing this with us.

editor@glue-it.com

Speedway

My hobby is speedway as we know it in Australia (not just solo bikes) but midget racing. I am involved in the vintage scene and have an actual 1960s vintage midget. Also, I have got back into slot cars (oval track obviously) the #98 here is of that car, built from an old slot car body I have had since 1969.

The #5 is also of that vintage and is exactly unchanged as I built it back then, but with a new chassis and bar work under it. The 1960s #26 roadster and the 1930s #81 are both scratch built from wood.

Ray Dean, Sydney