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Stuck Allen head bolt

gregfortin

Aluminum
Joined
Nov 20, 2016
Any suggestions? I bought a lot of cat 40 tool holders. Many of them had broken stubs of end mills and drills. I was able to loosen most of them with brute force and penetrants.
Three are really stuck. I’ve tried my impact gun an heat. Still can’t move them. Any ideas would be appreciated. Try drilling? Thanks
 

Thunderjet

Hot Rolled
Joined
Jun 24, 2019
Any suggestions? I bought a lot of cat 40 tool holders. Many of them had broken stubs of end mills and drills. I was able to loosen most of them with brute force and penetrants.
Three are really stuck. I’ve tried my impact gun an heat. Still can’t move them. Any ideas would be appreciated. Try drilling? Thanks
Well, Since it sounds like a salvage opp any anyway, I would go with the drill thingy.

I've had limited success with finding an old carbide die drill, and grinding the cutting edges reversed and turn the thing CCW.
Mount the workpiece in a mill and make sure it doesn't move. Go slow with feed and run it around 1/2 of the rpm you normally would run.
Many times the screw will back itself out as you go deeper.

Good luck.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Sometimes heating a thing from the item side to 300 degrees or so can get loose a tight bolt.

Sometimes drilling through, then soaking with penetrants for bolts but can't do that with broken stubs of end mills and drills

 
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ignator

Cast Iron
Joined
Oct 8, 2012
Location
Marion, Iowa
If you have enough sticking out of the broken end mill, put it in a bench vise, if you can bite it with the jaw, and use a strap wrench on the holder to rotate in the opposite direction of the end mill cutting rotation. The idea is to 'unload' the set screws from a slightly rotated endmill that is forcing the threads to be locked on the set screw.
 

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
The classic method for a stud is to put a nut over it and mig/tig weld it on. I would choose a nut that slips over the socket head and weld that on. The heat cool cycle will break the threads free. Never done it but it is often recommended.
I suppose you could drill a hole in one end of a long bar and use that instead of a nut. then use the bar as a wrench .
Bill D
 

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
Another method is to bore a small piece of metal, wood, or plastic so it just slips over the exposed head. Then drill a concentric. pilot hole clear through. Use this as a drill bushing to keep things centered.
Bill D
 

Conrad Hoffman

Titanium
Joined
May 10, 2009
Location
Canandaigua, NY, USA
I've had good luck with one of those tools that rotates slightly when you hit it with a hammer. Commonly used to remove the stubborn little flathead screws that hold brake rotors on some cars. Usually found in auto shops- KD tools? I think the combination of a sharp compressive blow, plus twist, is what does the trick. Holding true to my usual pessimism, sometimes nothing works.
 

Scottl

Diamond
Joined
Nov 3, 2013
Location
Eastern Massachusetts, USA
Penetrating oil, heat, impact driver and persistence.
Sometimes smacking the end of the broken end mill can also help "unload" the setscrew.

The fact that the mills are broken is a giveaway that the loading is there due to the same excess torque that broke the end mill. Turn it slightly in the other direction as ignator suggested and it may loosen.
 

gbent

Diamond
Joined
Mar 14, 2005
Location
Kansas
I am guessing you mean the end mill lock screw, not a bolt. If so, just throw the holder out and cut your losses. Chances are better than even that the end mill tried to turn under the screw and wedged plum tight. After you spend 4 hours getting the lock screw out you will discover the holder runs out to much to be useful.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
If you have not rounded out the hex yet, try a shake and break tool. Had some stuck allen screws last year that would not budge, even with the hammer impact extractor, they came right out with the shake and break. This is first link I could find, lots of mfrs, this is not an endorsement for this brand.
https://www.wivco.com/store/p3/Shake-N-Break™.html
 

hvnlymachining

Cast Iron
Joined
Jun 21, 2019
Location
St.Onge
The classic method for a stud is to put a nut over it and mig/tig weld it on. I would choose a nut that slips over the socket head and weld that on. The heat cool cycle will break the threads free. Never done it but it is often recommended.
Just did this yesterday for a twisted off bolt in a flywheel, job in and out in under 10 minutes. I've done it dozens of times, only a couple failed and required drilling out.
 

GregSY

Diamond
Joined
Jan 1, 2005
Location
Houston
I've never seen that shake and bake tool. Probably cuz I haven't touched my impact driver in over 20 years. I'm tempted to buy one, but then, I haven't touched my impact driver in over 20 years.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
I've never seen that shake and bake tool. Probably cuz I haven't touched my impact driver in over 20 years. I'm tempted to buy one, but then, I haven't touched my impact driver in over 20 years.

I'm kinda surprised by the fact I use hand impact tools frequently. They work really good when most other methods fail.
 

GregSY

Diamond
Joined
Jan 1, 2005
Location
Houston
Well...I'm referring to the 'air chisel' that would work with that attachment. I use air impact wrenches and other air tools. I probably used the term 'impact driver' incorrectly.

It's like how I was excited when I bought a Milwaukee 1/2 cordless drill and it came with a free cordless impact wrench. 5 years later, the drill is half worn out and the impact is still sitting in the drawer, never used.

Some tools never seem to be the right tool for the job.
 

gregfortin

Aluminum
Joined
Nov 20, 2016
All great suggestions. Thanks
I’ll try them and give you some feedback.
 

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Joe Henderson

Aluminum
Joined
May 21, 2006
Location
Blooming Grove, Texas
They make some stubby left hand easy outs that might work if the head is still intact. Drive the correct size on and unscrew it. Other than that find a shop that has a Tap Zapper. It's an EDM type of sinker that will get those screws and broken taps disintegrated.
 








 
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