ER20 collets, bang for the buck?

I can’t seem to find an answer from searching forum posts.
I am using the ER20 collets that came with my spindle, they’re good enough, but the other day I realized that I don’t have any spare collets, which is bad. I was about to order another random $15 set of ER20 collets, but figured I could use this opportunity to purchase a few higher-quality/lower-runout ones, instead of a set of average ones.

  • So at one end of the spectrum there are the $1-a-piece things
  • At the other end of the spectrum, there are the “Ultra-precsion” collets from PreciseBits , $40 a piece

Do you guys have a recommendation for a good “in-between” choice ?

I really only need one 1/4" and one 1/8", which covers 95% of what I do. Right now I’m leaning towards buying those two sizes only, from PreciseBits UP series. But the shipping cost to Europe will probably make me think twice.


I’m generally happy with Sorotec when it comes to the smaller collets (ER8). Their ER20 precision collets are 27€ and rated DIN 6499B class I.


Thank you, good to know about this German shop for this and other CNC things.
I see their collets are metric, and they state the 7mm one can squeeze down to 6mm, but I was never comfortable with using a collet that’s not the exact size of the endmill shank (especially since 6.35mm would be quite near the lower limit). Do you have any opinion on that ? Do you use your metric collets for imperial endmill shank sizes ?

As long as you stay within the specified clamping range you’re fine, the tool will fit nice and snug. I’ve used the regular-precision metric ER11 collets with the Carbide 3D tools for example without issues.

Where it’s not okay to use an Imperial tool in a metric collet is where the metric collet is only specified for the nominal tool diameter. For example these high-precision collets from FAHRION are only specified for the nominal diameter.

But more generally, I’ve been trying to move away from Imperial tooling and buy metric. It hasn’t been too difficult so far, there are plenty of suppliers, even here in tiny Switzerland.


Damen CNC sells “Swiss Quality” collets at seemingly competitive prices.

A thread on collets.


Thank you both, this gives me multiple interesting options.
(the bad news is, those Sorotec/DamenCNC sites induced gear lust in me again! must fight that)

My experience with the ER20 collets has been that, where I am using bits described in Inches there’s quite a bit of extra tightening on the collet nut just to get, e.g. the 6-7mm down to 6.35mm before you start clamping and it’s a lot more convenient to grab the 1/8, 1/4 and 1/2 inch collets to use for bits sold in Freedom Units.

Are the collets in their shop suitable for the makita rt0700c?

Oh yeah, I forgot about REGO FIX.

However the specs listed on damen cnc seem to be inaccurate. This collet lists “Run-out <5µm” in the description but if you look at the PDF attachment, it lists the REGO-FIX part number 112006000, which is 1120.06000, which per the REGO-FIX website, is part of the standard series, which has 10um runout.

If you want 5um runout, you need their UP line. For 6mm, that would be part 1120.06001. In Switzerland it’s a difference of 22 CHF vs. 36 CHF.

Seems a bit dodgy of them.


If it takes ER collets, it takes ER collets, doesn’t matter where you buy them.

Well ok, I don’t really know how the Makita collets are specified, but it takes the same as the Carbide stock spindle.

They’re not standard - so Carbide 3D’s are probably your best bet.


The Makita and Carbide Compact Router use the same proprietary collets.

In addition to the C3D set which @gmack linked a variety of other sizes are available from:


Thanks for the suggestions!

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I am curious if anyone knows where to get replacement collets for the PreciseBit collet sets. I got them from the previous owner of my machine and I’d love to replace at least one that I dropped on the ground but from what I understand, they are not a standard ER collet size and while $24 may be reasonable, I just want to know if there are any other options.

I have 2 PB nuts, wrench and 1/4 and 1/8 collets.

PM your address and I’ll be happy to send them to you

Pay it forward.