Diy Brushless Spindle

[blackburn mark]

iv never looked at the implications I think back to back is the standard but id fit them in which ever way was easiest to implement
I had to make a couple of washers with a grove in the face for the outer Belleville springs to sit in to keep them central and clear of the shaft

I "think" I pulled tension on the inner races via the spindle.... errr, no hang in, I used epoxy to lock one of the races.... bollocks! I cant remember now? when you have all the parts in your hands you'll make sense of it

tight fit on the pointy end bearing (housing and the shaft) and allow the other bearing to float to some extent so the Belleville washers can overcome any movement (if that makes sense)

EDIT: i assumed "back to back" meant open ends out?

[Point25]

Thanks Mark,

I think I have this assembled right but thought I would post some pictures to confirm and help others who have the same question.

I didn't quite get what you were saying about fixing the washers - I guess the aim is to center them to stop them rubbing on the spindle - seems like that might be quite difficult?

Cheers.

[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

[booski]

Hi there,

First post here and entirely new.

I just wished to contribute something. For my honours project for my degree, I made a desktop CNC machine.

Part of this project was to produce a simple spindle. To drive it I used a brushless motor, a small thing.

As you know, to control a brushless motor speed you need a servo tester. The trouble is, when you switch a brushless ESC on, you need to wait about 7/8 seconds with the servo tester at full off while the ESC initialises before turning up to the required speed.

Well, I designed my own speed controller using a simple PIC micro controller and program. It's designed as such so that it powers off the ESC's own servo supply. When power is applied to the ESC, the controller starts off at zero ignoring the speed dial for 8 seconds while the ESC initialises. Afterwards, the controller reads the dial and spins up the motor.

It makes the whole thing automatic and requires no manual intervention. Simply a delay from the control software on the host computer to accommodate for the ESC initialisation.

I'm curious whether there's any interest in this sort of thing as more brushless spindles come about? I've not seen anything like it before.

[Jonathan]

I'm curious whether there's any interest in this sort of thing as more brushless spindles come about? I've not seen anything like it before.

Yes I should think there is, at least for Mach 3 users. A long time ago I made a simple circuit using a PIC12F683 to interface between the parallel port PWM output and a standard ESC. However I didn't use it for long since, in addition to getting a standard spindle, I switched to LinuxCNC for which someone has already written the code to make the parallel port output the correct PWM signal for an ESC.

On a related topic, I recently put the motor I originally made into a spindle on to my Mum's bike. For that I used one of the electric bike speed controllers from eBay and added hall-effect sensors to the motor. As one would expect, it's far better than the sensorless controllers, especially at low speed, so if I was to make another brushless motor spindle I'd definitely control it with a similar controller:

48V/600W brushless controller for E - bike & scooter | eBay

They're also programmable, so you can set the current limit among other things, which could be useful for this application. I'll post a picture when I've got it off the other computer...