Author Topic: Correcting ER11 nut taper  (Read 1314 times)

Offline Neil-Lickfold

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Correcting ER11 nut taper
« on: May 16, 2019, 08:19:03 PM »
So I got some ER11 collet nuts. Had a piece that needed to run quite true. When I used one of the new collet nuts, it was out by more than 0.05mm. Used the genuine ER nut and it was fine.

So I set up made a spacer and checked the original with my set up and the taper on the nut ran within 0.01mm, the new ones were out by as much as 0.1mm. So I set up and recut the 30 deg front taper using the thread and the back shoulder as a reference. Picture shows the inverted bore tool and the compound set at 30 deg. Using a Regofix ER11 collet holder with the sleeve spacer for the nut to seat against.

I also set up and trimmed the outside with it just on the thread of the mandrel 1st. Cutting the inner 30 deg taper was a second op.

Now they are just as good as the original collet nut.



Offline Admiral_dk

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Re: Correcting ER11 nut taper
« Reply #1 on: May 16, 2019, 09:43:43 PM »
Hello Nick

So what you're saying is that the accuracy of the internal hole directly relates to the accuracy of the location of the collet ?

I guess that this makes good sense - though I must admit to thinking that the "socket" of the collet holder and the collet itself had more influence ....

Offline gerritv

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Re: Correcting ER11 nut taper
« Reply #2 on: May 16, 2019, 11:10:31 PM »
Unfortunately if the taper in the nut is off then it will likely force the collet out of centre as well. Sometimes you can get past that by tightening up more but there is a limit. (I was surprised at the torque requirements for ER collets when I saw then in print).

When you re-cut or regrind the taper, make very certain that your cutting edge is dead on centre, otherwise you end up with an elliptical surface. I learned that the hard way.

gerrit
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Offline Neil-Lickfold

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Re: Correcting ER11 nut taper
« Reply #3 on: May 17, 2019, 01:37:30 AM »
Yeah I too was surprised by the error in the nut and the effect it had. Clearly the thread clearance does not make it self align at all.
Checking that the tool is on centre before you start us also important. But if it is 0.05mm off it won't make any significant difference.

Offline dieselpilot

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Re: Correcting ER11 nut taper
« Reply #4 on: May 18, 2019, 02:06:50 PM »
Good ER collet and holder thread clearance is very small. Were these also Rego Fix nuts? I would guess not, as you wouldn't be fixing them at the prices they go for? I scrounge Ebay for name brand.

 

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