I'm trying to do the same thing. I want to add a small chuck to a small motor. No idea what to do.
Small Spindle Ideas? | Mambohead
I recently got a ER-20 collet chuck to use it attached to a motor rotor shaft. How I'm suppose to attach the collet chuck to the motor shaft that I wont get runnout? I want a direct drive, no belts or pinnions...
How its the ideal way of doing such thing? Will a heat shrink fitting work?
Also the fit must be strong enough to hold everything so it wont get loose when the spindle is machining.
You cant use a regular drill chuck, they cant stand high rpms, the regular ones might work for maybe about 5000rpm, and still there is another problem they have a lot of runnout...
ER-collet chuck is the way to go.
I'm still trying to figure it out if a heat shrink fit only will hold it on place or if I will need to weld it or something similar. It might hold but I dunno how smaller it needs to be and if its too small will it crack when it gets cold?
Just an observation.....motor shafts are relatively short compared to an ER collet assembly + cutter / drill / whatever, so forces on that area are liable to be greater, inducing a loosening of the joint. In a mill the spindle is somewhat longer in comparison and held between bearings. I fear your mounted collet may get a severe 'wobble on' and fling itself around the workshop after parting company with the motor!
In my case I will not use RC motor, but a induction motor, the shaft is not so short, and I will cut off the stock ER collet chuck in the size I need, most of them are so long. I've seen it done a few times, but still dunno how to properly fit em
Rotagrip - ER25 Straight Shank Collet Chuck 25mm Dia x 150mm
The straight shank ones are the ones that most of people use to make this, in the case of using rc motors most of the people use belt drive because indeed the shaft is too short. They have a hole in the middle but in any case don't think you wont need some lathe work or something to make it.
Make an adapter:
Take a piece of round stock, larger than the collet chuck shank. Bore one end of it in the lathe to a close fit on the collet chuck shank. Put a second piece of stock in the lathe and turn down to the same diameter as the collet chuck shank. Push the first piece onto the second piece. Fit the catch plate and drive dog to the lathe so you get the whole thing turning, not slipping, then bore the other side for a fit on the motor shaft.
Then glue. Engineering adhesive.
But does this loctite kind of glues work with heat? I know that some actually loosen with heat, motor shaft after working for a long time should have a temp of about 80º C, maybe higher...
I taught on doing it without glue, the motor shaft like 12mm and have the collet chuck holder bore with like 11.8 and put the rotor in the freezer and heat up the chuck holder to red hot, then press fit and let it cool down. Dunno if its strong enough to hold and or if after it cools down can the holder crack due to such large diameter difference
Most motors do not have adequate bearings for all but the lightest cutting loads. Side loads will wear out the motor quickly if it would work at all.
I will add another apropriate bearing to the motor, fitting on the collet chuck. The only problem is to get the information about the heat shrink fit...
Machine internal/external tapers to fit and hold together with a cap screw inside the chuck.