Previous in Forum: What's Causing all These Mass Shootings   Next in Forum: Reality is an illusion
Close
Close
Close
11 comments
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6507
Good Answers: 249

Siezed collet removal

06/03/2022 6:55 AM

A lesson learned:

I have a B&D grinding tool that had a frozen collet that refused all attempts to remove it.

It had frozen to the shaft.The metal of the shaft was so hard that vise grips could not hold it,even when a gorilla grip,between both knees failed.I finally decided to put a piece of coarse emery cloth around the shaft,rough side on the shaft. Then I applied the vise grips over the emery cloth and the Vise grips were finally able to get a grip,and I finally broke it loose.It was a very stubborn part,locked on by rust.I was afraid I would wring the shaft off before it broke loose.

I had already stripped the internal lock trying to remove it,and did not want to break any cooling fan fins.

I have ordered a new collet and nut,and I will apply Never Seize to the threads so this will not happen again.

The emery cloth trick is a good idea to spread around when working with hardened shafts of any type.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 22652
Good Answers: 409
#1

Re: Siezed collet removal

06/03/2022 8:43 AM

That brings back memories… and not good.

a grinder is no different…

What occurred is known as fretting. And what that is, is high speed vibrations that micro-welds the collet.

  • The causes can come from;
    a poorly manufactured too
  • poor installation of the tool (always clean the tool holder and collet before installing it)
  • a bad collet
  • etc..

the problem is, just replacing one item will not solve it, if a collet has micro-welds, it will pass it onto a clean tool holder, that can pass it onto a new collet, that passes it on and on…

when that happens, one can tap the collet or tool holder to break the micro-welds.

One should inspect you collet and tool holder before installing it.

Here’s an example of fretting, looks to be a BT tool holder… the collet it holds can happen also…

__________________
“ When people get what they want, they are often surprised when they get what they deserve " - James Wood
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6507
Good Answers: 249
#2
In reply to #1

Re: Siezed collet removal

06/03/2022 9:01 AM

This was not fretting or cold welding,it was just rust.

Wiping off the collet shaft with cleaner revealed no pitting or fretting of the shaft.After cleaning and burnishing,the collet shaft is still free of frets,pitting or cold-welding however the nut is pitted,so I am replacing both just to be sure,even though I would have no qualms about reusing the collet if absolutely necessary.I think the Never Seize will prevent future problems of this sort.

I just wanted to suggest a method of removing hardened shafts,that are harder than tool steel.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Register to Reply
Guru
Engineering Fields - Nuclear Engineering - New Member

Join Date: Sep 2009
Location: Louisville, OH
Posts: 1533
Good Answers: 29
#3

Re: Siezed collet removal

06/05/2022 5:08 PM

Did you try beating on the OD with it resting on something solid--like a vise or anvil? The slight radial deformations might break it loose. Same with frozen nuts, but might have to use a hammer on both sides.

__________________
Lehman57
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6507
Good Answers: 249
#4
In reply to #3

Re: Siezed collet removal

06/05/2022 7:45 PM

I got it off by using the Emory cloth and vise grips,as stated in my original op.I was simply passing along a tip about gripping very hard surfaces that are harder than tool steel.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30321
Good Answers: 817
#5

Re: Siezed collet removal

06/06/2022 7:29 AM

A standard way of freeing-up nuts and bolts that have rusted in storage is to heat them up with the propane gun, and immediately drop them into a bucket of water.

A bit 'McGuyver', perhaps, though it does the trick.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6507
Good Answers: 249
#6
In reply to #5

Re: Siezed collet removal

06/06/2022 7:52 AM

I have done this on many things,but not on items surrounded by plastic.

This method is particularly useful on exhaust manifolds,or aluminum parts with steel setscrews,as the two metals have a different thermal expansion rate.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Register to Reply
Power-User

Join Date: Mar 2019
Location: 3rd rock from the sun,a small dust mote,in a small insignificant spiral galaxy referred to locally as the Milky Way
Posts: 143
Good Answers: 3
#8
In reply to #6

Re: Siezed collet removal

06/11/2022 10:50 AM

A particularly hard setscrew to remove was in a large 300hp fan,and was finally broken free by heating the aluminum fan hub,and then quenching it with freezing cold ice water.

The different expansion rates broke the bond and the screw finally was removeable.

This became a SOP for this type problems in the machine shop.

Exhaust bolts are very hard to remove because the bolts get very hard due to the repeated heat.cool cycling.They normally cannot be drilled with hss drill bits,must use carbide bits.

The use of the proper EZ out tool is important.The spiral type tend to expand the bolt making removal more difficult.I have found that the square tapered profile with cutting grooves on the sides does a better job without expanding the bolt very much.GM makes that type,and is the only type I use,even though I have plenty of the other type.

If you really want to make a assembly shake/vibration proof,drill a small hole with right hand threads in the bottom of the hole,and a larger hole with left hand threads in the top half of the hole.If either tries to loosen,it will be prevented by the other screw.Use a cup-point,serrated tip setscrew.

The holes should be appropriately sized to let the smaller set screw go through the large threaded hole.

↑(Of course,this ↑ is common sense,but common sense is so rare anymore,I wonder why the call it common?No offense intended,just trying to eliminate the obvious questions or comments that may follow).

This method is simply using a modified version of a method used by nature for millions of years in the cucumber vine.Half of the curls are clockwise,the other are counter clockwise.Pull on the curl,and one half loosens,and the other half tightens.

__________________
There is no darkness except for ignorance..Shakespeare
Register to Reply
Power-User

Join Date: Mar 2019
Location: 3rd rock from the sun,a small dust mote,in a small insignificant spiral galaxy referred to locally as the Milky Way
Posts: 143
Good Answers: 3
#9
In reply to #8

Re: Siezed collet removal

06/11/2022 10:56 AM

This also works when coiling up a hose or cord.

Reverse the winding direction about half way through,and it will prevent kinking when you unwind it.

You're welcome!

__________________
There is no darkness except for ignorance..Shakespeare
Register to Reply
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5285
Good Answers: 287
#11
In reply to #8

Re: Siezed collet removal

06/28/2022 7:27 AM

Common sense is the most fairly distributed thing in the world, for each one thinks he is so well-endowed with it that even those who are hardest to satisfy in all other matters are not in the habit of desiring more of it than they already have.

René Descartes

__________________
We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Register to Reply
Guru
Engineering Fields - Nuclear Engineering - New Member

Join Date: Sep 2009
Location: Louisville, OH
Posts: 1533
Good Answers: 29
#7
In reply to #5

Re: Siezed collet removal

06/06/2022 10:51 AM

A variation is to get the nut red hot, then put the wrench to it. This temp apparently changes the ferric to ferrous--or the other way 'round, I get them mixed up--which takes up a bit less space and should let the nut move. but it may also destroy any heat treating on the original bolt or nut. Of course, as HTRN says, cannot be used near plastic, rubber, or similar materials.

__________________
Lehman57
Register to Reply
Guru

Join Date: Sep 2008
Location: Where the sun sets on OZ
Posts: 1366
Good Answers: 27
#10

Re: Siezed collet removal

06/27/2022 5:59 PM

Yes, a good idea. Also you can use emery cloth as a "washer" under the threaded collar used to clamp cutting discs in an angle grinder. Put the abrasive side against the disc and then the cloth backing goes against the collar. This makes it easier to undo.

The rusting of the collets comes from your fingers. You do the right thing by making sure the collet is clean when inserting but using your fingers to do this causes the rust. An old ( oily ) rag is "de rigeur."

__________________
Where's the KaBoom? There should be a KaBoom!
Register to Reply
Register to Reply 11 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

HiTekRedNek (3); hitekrednek2 (2); JIMRAT (1); Lehman57 (2); phoenix911 (1); PWSlack (1); Randall (1)

Previous in Forum: What's Causing all These Mass Shootings   Next in Forum: Reality is an illusion

Advertisement