Fingers crossed it'll cut ally

[Jonathan]

anyone using small motors (engraving) might get away with an old PC power supply... they have 5v and 12v coming out of them

If you're careful you could even put the computer PSUs in series. Just need to make sure they're isolated. I considered doing this for my stepper motors since I've got plenty of 350W (or so) PSUs from the local car boot and if I put 6 in series that would have given a nice 72v for my stepper motors. I decided against this as 6 of those would have been a bit bulky and a good toroidal transformer came up on eBay.

A cheap way of providing the 5v supply is just using a 5v voltage regulator. Any would probably suffice since it's only providing a few miliamps in this application.

With regards to my big motor I think I could get away with the 100mm shaft collet holders. I'd probably get the 1/2" one and reduce it down to 12mm. The motor contains 4 bearings, 3 of which are 2112 bearings and one big 6089. I shouldn't be too difficult to change them but it is worth it? The biggest external diameter bearing that would fit without doing something imaginative is maybe 24mm. I can't find any angular contact bearings that would fit there.
I've been thinking of using this motor for a 4th axis / lathe but I wont go too off topic!

[blackburn mark]

yo jonathan,

i was terrified of turning down an over sized shaft so i spent weeks looking for the right size, its being shipped as we speak

im gutted you didnt find a 150mm one, im convinced it would have been easy to stick double row A/C on the nose in a shallow housing,, ill find out as soon as my shaft turns up ill start doing a bit of turning

im not totaly convinced a double row A/C bearing will be tight enough for ally, the ones iv got dont feel like they have that much pre-load, i might end up stacking the two of them

4th axis... mmmm im thinking a 100mm rotary table with my 5th stepper melded to it

im not sure anything is off topic,, is it?

[Jonathan]

i was terrified of turning down an over sized shaft so i spent weeks looking for the right size, its being shipped as we speak

Hah, I was pretty scared dismantling this motor. It was all glued/loctited together and needed some persuasion with a hammer.

im gutted you didnt find a 150mm one, im convinced it would have been easy to stick double row A/C on the nose in a shallow housing,, ill find out as soon as my shaft turns up ill start doing a bit of turning

There are 150mm ones, but they're more than twice the price of the 100mm. I could probably extend the 100mm one if it came to it - definitely some thinking to do before I buy anything!

im not totaly convinced a double row A/C bearing will be tight enough for ally, the ones iv got dont feel like they have that much pre-load, i might end up stacking the two of them

I see, so you don't think the ones that are currently in my motor would be up to it? Maybe I could link this motor to the existing milling machine spindle via a pulley...then I needn't worry about angular contact bearings. Having said that I don't know if the bearings in the spindle of my machine are up to 6000rpm.

4th axis... mmmm im thinking a 100mm rotary table with my 5th stepper melded to it

Yep, that's what I did except with a 150mm vertex rotary table. It's excellent for making pulleys:



And making 4th axis'

im not sure anything is off topic,, is it?

:) well in that case this is the 4th axis/lathe design I've started making:





I'm using two tapered roller bearings in that. The gold things are solenoids to create a sort of disk brake which I'm hoping will hold it steady enough for me to mill will it aswell as using it as a lathe by swapping to a bigger motor...the brushless one.