Using RC Brushless motors as spindle

[M250cnc]

I did the mount today, not the neatest of things I've made with the rotary table but it works:

(Picture tomorrow)

I was under the impression your mill was under cnc control why the RT ?

I ran the motor in for about 5 mins on 12v, soon got bored of that (I'll leave it running properly tomorrow).

Its a temperature thing if it doesn't get hot just keep increasing the speed in increments.

It merely drew 550w and about 53 amps. I'll have to think of a safer way of testing the power at higher voltages.

I think I'll stick with the batteries for now unless anyone can point me to a 50v PSU that can deliver a LOT of current. Maybe a few of those switching PSUs people have been using for steppers on eBay...

Sounds like mum & dad are gonna have a big leccy bill coming.

Phil

[Jonathan]

I was under the impression your mill was under cnc control why the RT ?

I took the steppers off the milling machine and put them on the router. Didn't want to put them back just for one part. Rotary table was also the most accurate way I could make the hole for the spindle, not having a boring head.

Its a temperature thing if it doesn't get hot just keep increasing the speed in increments.

That's good, the bearing didn't get hot at all. ESC warmed up a little but that's all. I'll leave it running on 3100rpm for a while today and see what happens.

Sounds like mum & dad are gonna have a big leccy bill coming.

Hmm, didn't think of that - and nor have they :naughty:
The batteries I'm using to power it were going to be charged from my wind turbine. If only I had space to mount it...

I measured the runout again now it's mounted properly. I put a 10mm cutter in and measured 0.03mm about 10mm from the collet. If I put the DTI on the collet chuck itself it reads 0.01mm.

[M250cnc]

I took the steppers off the milling machine and put them on the router. Didn't want to put them back just for one part. Rotary table was also the most accurate way I could make the hole for the spindle, not having a boring head.

4 jaw chuck on the lathe ?

I measured the runout again now it's mounted properly. I put a 10mm cutter in and measured 0.03mm about 10mm from the collet. If I put the DTI on the collet chuck itself it reads 0.01mm.

Are you measuring the outside or the inside of the chuck for runout ?

You should be measuring the inside and i would measure at the extremes of the taper to see if you have different amounts of runout at the two points.

Phil

[Jonathan]

4 jaw chuck on the lathe ?
Are you measuring the outside or the inside of the chuck for runout ?

You should be measuring the inside and i would measure at the extremes of the taper to see if you have different amounts of runout at the two points.

It wouldn't fit easily on the lathe - it's only a C3 mini lathe with 4" 4 jaw chuck. I probably could have got it to fit, but it wasn't worth it since I needed the rotary table to do the semicircle on the outside anyway. Wish I had a lathe like yours...made so many things on the same one at school.

I used the lathe with 3 jaw chuck for a few of the bearing mounts for the screws - carefully designed the shape to fit the chuck easily.

I measured the runout inside. I'll try again like you said.

Just tried cutting with it. 7mm two flute cutter and some scrap aluminium. Using 0.5mm depth/width of cut it was happy. Sometimes 1mm, machine is a bit too wobbly to do more at the moment. I'll post pictures in a minute to save a thousand words...







The motor drew 30w extra whilst cutting, 100w idle.