Diy Brushless Spindle

[blackburn mark]

I think you where right in you description of "back to back" sorry :(
you are pushing the inner races apart
as long as the bearing closest to the tool end is tight on the shaft and in the housing I'm guessing all will be well

....now I think about it the inner races shaft and spring washers will all rotate which may be a good reason to go "face to face" because if the washers aren't perfectly central they will cause resonance at high revs

"face to face" would mean the washers don't spin with the shaft as they push against the outer races
that's why I remember "pulling the shaft" so to speak

with the springs between the outer races you need to grip the shaft to hold the tension... in my case I simply used the out runner bell to grip the shaft and hold the tension (not good for your outrunner bearings) what I should have done is add a collar with grub screws, I did have one but I hadn't accounted for the extra room it would take inside the bearing housing

if you don't get what I mean let me know and the next time I'm at home ill take some pictures of mine or knock up a drawing

in a nutshell, instead of pushing the inner races apart from the inside you are pushing them together from the outside

you may suss a better way of doing it ?
let us know how you get on

[totts]

I use a comtroller from http://www.logicnc.com/rcnc.html

Its a bit strange at picking a speed at times but in a program it seems to run fine, many of hours running with this and enables fully automated control of my brushless spindle.

[dlang]

I use a comtroller from http://www.logicnc.com/rcnc.html

Everything I try to go to on that site asks for a password, is it still live?

[GordonFreeman]

Just got done with my DIY Brushless spindle. I had everything but the ER16 stub laying around. I'm using an old 320 kV motor and a VESC speed controller (skateboarding). First tests have been very promising, compared to the Colt trim router I'd been using.

The VESC will hold the RPM very close under varying loads. I've only tested it on 6S batteries, but my CNC runs on 42V so that should be close to getting it to speed.

I cast the adapter tube in Urethane (again, stuff laying around). A lot of work, but not bad for only needing to spend $20.

The VESC BLCD software will show volts, amps, etc. live if it's hooked up via USB. I always thought it would be a neat idea to slow the feed rates down based on load. I'm running LinuxCNC but have no idea how I'd hook all that up.

[dlang]

did you attache the stub directly to the motor? or did you build bearings between them?

[GordonFreeman]

I put 2 additional bearings on the stub and then a coupler from the stub to the motor. It's all held together by the casting. Everything lines up good, I just made a solid couple (no flex) hopefully that will be ok. Can't wait to try some actual work with it.

[totts]

Also heres a video

http://youtu.be/XKCUqyvt1RA

[njhussey]

What you trying to cut? This will influence what KV motor you use etc...

[Snowy]

Hi there,
i'd like to be able to cut alluminium but also softer stuff like plastics and wood. Do you think it could be suitable for steel also? i thought it would be too weedy?

[njhussey]

You'll never get one spindle to cut everything. Steel needs slower speeds, typically a few hundred rpm up to a couple of thousand, what it really needs is torque and lots of it! Wood and plastic on the other hand need higher rpm and feeds. You're best not thinking about steel on a router and just buying a mill if you want to do steel. In all honesty you're better off buying a 2.2kW water cooled spindle for just under a couple of hundred quid which will do all you want with consument ease...I've got a home made brushless spindle and I've not bothered using it. I will do on something but not sure what yet...

If you still want to make one then use a feeds and speeds calculator to work out what speed and power you want for the materials you're wanting to cut and then look at something like a 5565 brushless dc motor (look on hobbyking) 170kV to 270kV outputting approx 2kW coupled to a 100A ESC.