ER11 collets for China spindles

Hi all, I just pulled the trigger on a Zhong Hua air cooled 1.5k 110v 80mm spindle/ VFD. Ran it for a while and it seems good, so quite. I noticed the collet looked a bit small (ER11) and tested one of my end mills ( all 1/4") to see how it fit. I was able to force the end mill into the collet but when screwing it on to the spindle I was only able to get about 4 to 5 turns cranking it. That’s not a lot of threads. Zhong Hua is made by Huanyang. For those out there that these spindles from China is this the norm? Is there any chance of a ER16 upgrade that will mount on the spindle?
Thxs RD-

Chances are you have a 6mm collet, not a 1/4" one. You can’t use a ER-16 collet or nut with an ER-11 setup. But you can get ER-11 collets in various sizes. The nuts do come in different thread pitches (at least the ER-20 ones do) so you may not be able to just buy spare nuts without verifying they are correct. But one nice thing is to get a nut for each collet size then paint each nut a different color so you can quickly grab the correct size collet/ nut. Lots of sellers on ebay. If buying nuts look for ones that have been balanced (you’ll see drill holes in the side of the nut).

1 Like

Thanks, I’ll hunt for a 7mm collet for a ER-11, seems I’m hunting everything down for this spindle. The cable they give you is 22 awg and 24" long (!). To build a longer cable I finally got them to tell me what Aviation connector they use, it is a GX19-4PB. I think they mean GX19-4S since it is a socket. Anyhow that item (GX19) only exists in China. So I have to play around with what I got and figure out how to re-use the connector it came with.

Given that the ER11 collets max out at 1/4"/6.35mm, which does not give a lot of metal to grip, perhaps trying to find the exact size collet is safest.

1 Like

Some of the collets specify they will work within a range that might include 1/4" but I would get one specifically made for 1/4". I would also get one for 1/8" as you can find small end mills on ebay for cheap that have an 1/8" shank.


I purchased an ER11 collet nut and a 1/4" and a 1/8" collet on Amazon. Works great. Like what was said in a previous post the one that comes with the spindle is 6mm. The only collet nut that will fit your spindle is an ER11.

1 Like

Thanks, I did something unusual today, I read a Chinese spec manual that came with the spindle. It states via a drawing and spec table the spindle supports up to a 6mm collet (arrrrg). Took the collet out again and saw indeed (with magnification) there is a 6 stamped on it. So I’m hoping the 1/4" we ordered yesterday (below) will pop in. Thanks again.

1 Like

That information should only apply to the specific collet that was shipped with your spindle, having a clamping range from 5.5mm to 6.0mm. The total clamping range of the ER11 system is from 1/32" to 7/64" with all the metric falling in between from 1mm to 7mm.

In your case you should be good to go with what you’ve purchased to accommodate your 1/4" tooling.

Attached is a link to a .pdf that charts the ER collet system and provides the clamping ranges for each system and for each collet in each system.

FYI, I removed my earlier post regarding ER interchangeability. According to further research into the subject, I was providing misinformation. It does not appear that one can simply swap a collet system by changing the spindle’s nut and I was seriously hard pressed to even find adapters. One could probably machine an adapter but I think we’re both committed to just finding industry standard tooling that works with the clamping ranges we’ve settled on since that’s the more supported route.

1 Like