Tegara ER32 Slot Style Ball Bearing Collet Nut 202-1574 P[

A worthwhile upgrade from the stock ER32 nut. Greater clamping power with less effort due to the bearings. Awin win in my books.

Given the price, my expectations were not high... I was initially pleasantly surprised by the fit and finish. After using it a few times and getting excellent concentricity, curiosity got the better of me and I disassembled it to check out the bearings and see if there was any indication of wear. Disassembly is pretty simple - remove the sealant from the small grub screw on the side, remove the screw, and then rotate the inner part of the assembly to remove the balls one-by-one. There are approximately 30 balls (didn't count them, sorry), and the handful that I mic'd were all on the same tenth. The bearing races were ground to an impressive finish, and showed no signs of contamination or uneven wear. Speaking of contamination - I was shocked to find an o-ring on the inner side of the bearing to prevent the grease from being washed out when using through-coolant.This seems to be the real deal, even if the price is a fraction of what a big-name ball bearing nut would cost.

Seems nice but haven't used it yet. Be aware that If you buy this you'll need a special wrench. Ordinary adjustable wrenches won't work, and neither will typical spanner wrenches that typically have 3-4 tangs. This one will only accept a single-tang tool.

I bought this hoping to fix runout on a cheap set of collets. Well, nope. But it did make the runout consistent for each collet. With the old nut I could get different runout by simply lossening and retightening. This one is smooth and I really like it. Another review said it was a 4 slot nut but mine is the standard 6 slot.