Thread: Diy brushless spindle
You require two magneto/angular contact bearings and they need to be pre-loaded, hence Belleville washers are mandatory, unless you can find a matched pair of bearings but that wont be cheap. There are sellers with 8mm angular contact bearings on Aliexpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China.
Thanks Jonathan - looks like finding the Belleville washers is going to be the hardest part, wonder why they are so rare.
I have spoken with www.simplybearings.co.uk but they need to know more tech info to allow them to advise - any idea what I should be asking for.... or perhaps there is another (afforable :-) bearing in their range which would get round the Belleville washer requirement?
Hi, I now have what I think I need - 2 Magneto Bearings and some Belleville washers :-).... now just wondering how to arrange the bearings and washers in relation to oneanother?
Do I put the 2 bearings back to back - ie with their 'open' faces both towards the inside and the washers separating them?
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?
Last edited by blackburn mark; 01-03-2013 at 10:31 PM.
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?
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
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.
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...
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.
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