Removing a stripped(ish) hex c'sunk bolt

[Sprogginz]

I need to replace the blades from a garden chipper.
The last bolt is stuck. All I have been using is an allen key.


I sprayed WD40 on it and left it for a couple of hours but no joy.
Can anyone suggest what I can do next?
I thought about buying one of those impact drivers that you whack with a hammer or mallet but are there better options?
Thanks very much.

 

[foxhole]

Have you tried heat?

 

[Mike13]

buy a stubby left handed drill bit set that goes from quite small to about the same diameter as the thread root. drill small first.
If it is off center then on the next hole try and guide it to the middle, keep going in small steps.
When there is only a thin bit of the bolt left it should come loose and spin itself out the hole.
Worst case is that you end up turning the bolt into a helicoil, it will then be possible to peel it out

 

[CBW]

Looks tricky, does it move at all?

 

[Mottie]

Many brake discs and drums on cars are held on with a countersunk bolt with a hex drive. Often the torx drive strips when the bolt is tight. Just drill the head out with a large drill bit and when it’s off, there will be no pressure left on the thread and you can usually wind them out using just the pressure of your thumb.

Another way that will work is using a centre punch. First tap near the edge of the head at 90° to make an indent, subsequent taps with the punch at an angle in an anti-clockwise direction. Use the smallest hammer you have so as not to bent the mounting flange.

Here you go, even a woman can do it! Joke!

 

[Sprogginz]

Have you tried heat?

I've only got an electric heat gun, would that be hot enough?
I've heard this before but I don't understand how this works exactly. What does the heat actually do for this situation?
Surely I'd have to let it cool down otherwise the metal might be too soft and break off?
Thanks.

 

[Sprogginz]

Looks tricky, does it move at all?

Not at all, to make it worse it's on a disc that rotates so I can't lock it in place enough to get good leverage when I turn the allen key or whatever I can use. I'll have to take the disc off but I need to find a 30mm spanner first and that's if the central nut is not stuck as well!

 

[foxhole]

I've only got an electric heat gun, would that be hot enough?
I've heard this before but I don't understand how this works exactly. What does the heat actually do for this situation?
Surely I'd have to let it cool down otherwise the metal might be too soft and break off?
Thanks.

Heat caused metals to heat at differing rates breaking the seal .A spanner thru a slot to the bolt head I can see below the blade will help lock it in place .

 

[Tigercubrider]

You could try heat plus,
find a torx bit that is a close fit and hammer in it.
sometimes a slight clockwise move before anti-clockwise helps.
with the heat, some plus gas may help and track down?
You’d heat and apply the fluid, wait a day, repeat, then try undoing it
or a dremel to make a slot

 

[Old Salt]

Get a large blade flat screwdriver and drop/push it through those slots, that will help you to lock the shaft. Put all the other bolts back in and tighten them up. Use some lubrication so they dont become stuck. Spray some penetrating oil on the stuck bolt and soak it overnight. Then try to undo the stuck bolt, by all means use your heatgun it will expand the bolt and hopefully free off any corrosion that is binding the threads.

 

[Harry Bloomfield]

Do not try any serious hammering, there is no support under the disk and it will bounce and/or bend it.

Heat and/or plus-gas, with a good Allen key or if the socket is damaged, find a bit which can be tapped in.

 

[oldbutnotdead]

If you can lay your hands on an electric impact driver (Aldi etc sell battery ones for £30) it might help. Those hammer hitting ones need something solid to work against.

 

[conny]

Heat gun will not be any use as it will also heat the surrounding metal. You need fierce direct heat on the bolt head and it needs to heat up quickly before the surrounding material can heat up. A small gas blow torch will be sufficient but don't use any releasing agents at the same time!!!

As stated above, you will need to lock the backing plate plate in position to prevent turning the whole blade.

 

[JohnD]

If you have to drill it, use a LEFT-HANDED BIT.

The heat, vibration and torque have a good chance of winding it out.

 

[Mottie]

I wouldn’t bother with any of the above methods until you’ve given it your best shot with the Allen key and it either snaps or rounds off.