I recommend getting the 1/4 inch collet. That way you can use 1/4 inch endmills. When milling you want to use the shortest and biggest bit you possibly can, and there’s so many 1/4 inch mills on amazon, that’s what I would do.
If by shim, you mean the 3d printed spacer used to fill out the Dewalt mount here is a couple pictures.
I do not remember the thickness of it. It was hard work putting it on the Makita, but the whole thing slid easily into the dewalt mount afterwards. A little bit of tightening the screws on the mount and good to go.
I’m not taking it off to measure it, that’s for sure
But I’ll see if I can get the measurements from the .STL file (it is linked to somewhere here on the forum )
I made a shim out of 2.75" aluminum pipe: http://www.amazon.com/gp/product/B00ARCNRTW — 16 gauge (~0.065", it was ~1.651mm thick) it would’ve been better at 2mm thick (if I could’ve gotten that to fit — still not sure if it would, and still debating about buying a 2mm thick pipe).
16 (0.0598, non coated) or 14 (0.0747, non coated) gauge was what I was going to look into. I think 14 gauge would be perfect as is just slightly under 2mm. I guess I’ll have to wait and see once my Makita gets in!
you could also buy a Extention Collet Chuck. but this works for me even whit 3000 rpm, if you go higher than 5000 rpm its better to have a perfect fitting cone shape.
Whit the makita and a R11 collet it’s clamped in the cone of the makita and you center it whit the nut