Anyone know where to get an ER20 collet nut?

I have bought 6 nuts from three different sources: 1 from Amana via Amazon, a pack of 4 from QWORK via Amazon, and 1 from MariTool bought direct. All of these have the retaining ring that the collet snaps into milled off center to the degree that they are unsusable.

So does anyone have a reliable source for ER20 Collet nuts?

The taper on the inside of the nut will be milled off center to a degree, that is what allows you to snap in and eject the collet from the nut.

You can see this in this video where they show the inside of the nut:

Not sure if that is what you’re speaking of but if it is this is as intended.

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Copied the wrong time offset in that video:


Thanks, yup that was what I was talking about. Strange that the one that came with my spindle was dead center. I guess I can stop returning nuts LOL.

Make sure the nuts are balanced. They will have a drill mark or two where some material was removed on the heavy side. A spindle running at up to 24k rpm needs balanced nuts.

The Maritool will be balanced for sure. But not certain about the others.

EDIT: I took a look at the two Amazon links you provided - neither of those would be acceptable to me. They clearly are not balanced and likely cheap Chinese offerings. Stick with Maritool - not that expensive, made in the USA, and balanced.

i bought a few Balanced ER20 Collet Nuts from AvidCNC, $12.95 each

I bought these off of ebay. Last October they were $29. I have an HY spindle and they fit just fine.