Broken hex bit stuck in machine, help!

[Helvetica]

Setting my planer blades today and the very last grub screw got a split, got really tight, and then I got that awful soft turn as I felt the hex bit give way and shear off. I was using a 10” bar and was definitely over tightening it! (The split made it tight).

So now it’s embedded a centimetre into the planer cutting cylinder and I have no purchase to get it out. Tried drilling with a small hss bit but it’s leaving zero impression any ideas?

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[Trevanion]

If they wanted you to tighten it any tighter they would've given you a bigger Allen key!

It's going to be an absolute PITA to get that out. Your best bet would probably be to drill it with either a Cobalt drill or a Tungsten Carbide drill as the stuck tool is going to be hard and then use some kind of screw extractor. Although I would first try getting something like a centre punch and see if you can get any movement by tapping it backward anti-clockwise, even if you manage to just dislodge the tool it's a bonus.

 

[finish_that]

Firstly , avoid any screw extractor , they are utterly useless for that type of problem , they only work when there is nothing seized or tight... otherwise they snap and cause more problems
You need to remove the broken hex from the cap head , likely this will only come out with the deft use of a sharp and tiny chisel.
Once the hex is out remove the bolt , if a hex no longer works you can try hammering a torx bit that is too big for the hex in or drilling with a left hand drill (worth getting a set in as they are very useful for this type of issue)
As in this application the clamping force is from the nose of the bolt back its extra tricky , normally the bolt head is taking the force and removing that releases the thread , you might get away with removing the cutter block and drifting the actual cutter blade out from under the nose of the bolt.
good luck!

 

[kevinlightfoot]

Is there room to get a small arc welding rod on to the hex bit ,strike on to it and then pull out the offending part using pliers.It might spatter a bit in the thread but once the grub screw is out you could cleanthat up with a tap,just a thought,it has worked for me in the past.Of course you would need an arc welder and be able to use it.

 

[novocaine]

centre punch.
give it a wack.
use a magnet to pull out the snapped bit.
don't be so rough next time.

 

[Helvetica]

Ha! I like this one, quick practical advice, and a slap on the wrist for machine abuse!

 

[autotrans]

Good smack with small chisel if u can get to it

 

[Inspector]

Carbide mini burr rotary files in a high speed drill, rotary grinder like a dermal or air die grinder will cut those with ease. Used to drill through broken screw extractors with them so we wouldn't damage aircraft structure.

Pete