Best tool for cutting heads off bolts
Discussion
Had a bit of an issue with a rounded bolt yesterday while changing the rear shocks on the 330i. Luckily a combination of blow torch and impact wrench got it loose. However, for those occasions where such a strategy is ineffective and another option would be to just cut the head off the bolt, which is the best tool to buy?
I know people mention Dremels but are these considered the best option? Do you need to buy special (toughened?) cutting discs for them.
Interested to hear your experiences and advice.
TIA
I know people mention Dremels but are these considered the best option? Do you need to buy special (toughened?) cutting discs for them.
Interested to hear your experiences and advice.
TIA

steveo3002 said:
angle grinder and 1mm cutting disc
^^^This is weapon of first choice!If access is a problem then I use a Dremel with the flexible extension.
You need the cutting discs which look like mini versions of the big ones, Dremel 426 or their speedclic SC456B. Be careful as they don't like any side force being applied.
The red ones just tend to explode on contact!
Chris32345 said:
Dermal is okay on something like a small screw on 8mm bolt
It will not touch a large hardened steel suspension bolt it just does not have the power
For that you need an angle grinder or air powered cut off wheel but need a good compressor to rub one of those
Our mileages clearly vary! It will not touch a large hardened steel suspension bolt it just does not have the power
For that you need an angle grinder or air powered cut off wheel but need a good compressor to rub one of those

True it won't be as fast as for one thing it's a lot smaller but if you can't get a full size angle grinder into the available space then it's another option.
Last big job with mine was the o/s/r inner sill body mount on my RRC - cut off the bolt & the old mounting plus cleaning up to good metal before using one of Froggatt's Easy On mounts. Not a hope of getting the big grinder in to most of it.
(FWIW I can recommend Froggatts Easy On stuff)
Penelope Stopit said:
Fastpedeller said:
Use walldrive design sockets and don't bother with cutting the head off the bolt?
Is shearing the bolt head off better than cutting it off?Fastpedeller said:
Penelope Stopit said:
Fastpedeller said:
Use walldrive design sockets and don't bother with cutting the head off the bolt?
Is shearing the bolt head off better than cutting it off?g3org3y said:
Had a bit of an issue with a rounded bolt yesterday while changing the rear shocks on the 330i. Luckily a combination of blow torch and impact wrench got it loose. However, for those occasions where such a strategy is ineffective and another option would be to just cut the head off the bolt, which is the best tool to buy?
I know people mention Dremels but are these considered the best option? Do you need to buy special (toughened?) cutting discs for them.
Interested to hear your experiences and advice.
TIA
Ok thenI know people mention Dremels but are these considered the best option? Do you need to buy special (toughened?) cutting discs for them.
Interested to hear your experiences and advice.
TIA

Penelope Stopit said:
Fastpedeller said:
Penelope Stopit said:
Fastpedeller said:
Use walldrive design sockets and don't bother with cutting the head off the bolt?
Is shearing the bolt head off better than cutting it off?g3org3y said:
Had a bit of an issue with a rounded bolt yesterday while changing the rear shocks on the 330i. Luckily a combination of blow torch and impact wrench got it loose. However, for those occasions where such a strategy is ineffective and another option would be to just cut the head off the bolt, which is the best tool to buy?
I know people mention Dremels but are these considered the best option? Do you need to buy special (toughened?) cutting discs for them.
Interested to hear your experiences and advice.
TIA
Ok thenI know people mention Dremels but are these considered the best option? Do you need to buy special (toughened?) cutting discs for them.
Interested to hear your experiences and advice.
TIA


A few years ago, having rounded off a bolt head Oops! I searched out the wall drives, and much to my surprise the bolt was removed (and of course binned) despite the head being pretty far gone. The wall drives are now my 'tool of ist choice' rather than the one 'of last resort' Can't recommend them highly enough. I don't sell them BTW

Fastpedeller said:
Before the bolt head is rounded is the ideal time for the wall drives of course 
A few years ago, having rounded off a bolt head Oops! I searched out the wall drives, and much to my surprise the bolt was removed (and of course binned) despite the head being pretty far gone. The wall drives are now my 'tool of ist choice' rather than the one 'of last resort' Can't recommend them highly enough. I don't sell them BTW
Never used them, will take a look at some
A few years ago, having rounded off a bolt head Oops! I searched out the wall drives, and much to my surprise the bolt was removed (and of course binned) despite the head being pretty far gone. The wall drives are now my 'tool of ist choice' rather than the one 'of last resort' Can't recommend them highly enough. I don't sell them BTW

Penelope Stopit said:
Inox cutting disk in an angle grinder has never failed.........................................yet
Unbelievable things those discs. I cut a seized bearing off a shaft with one yesterday. It actually cut through the casing and the middle of the ball bearing. The only thing I don’t like is the dust. Oh and the sparks are mega hot as well. Penelope Stopit said:
Fastpedeller said:
Before the bolt head is rounded is the ideal time for the wall drives of course 
A few years ago, having rounded off a bolt head Oops! I searched out the wall drives, and much to my surprise the bolt was removed (and of course binned) despite the head being pretty far gone. The wall drives are now my 'tool of ist choice' rather than the one 'of last resort' Can't recommend them highly enough. I don't sell them BTW
Never used them, will take a look at some
A few years ago, having rounded off a bolt head Oops! I searched out the wall drives, and much to my surprise the bolt was removed (and of course binned) despite the head being pretty far gone. The wall drives are now my 'tool of ist choice' rather than the one 'of last resort' Can't recommend them highly enough. I don't sell them BTW

markcoznottz said:
Penelope Stopit said:
Inox cutting disk in an angle grinder has never failed.........................................yet
Unbelievable things those discs. I cut a seized bearing off a shaft with one yesterday. It actually cut through the casing and the middle of the ball bearing. The only thing I don’t like is the dust. Oh and the sparks are mega hot as well. markcoznottz said:
My mate raves about those snap on wall/ flank drive impacts, I haven’t seen them in action, i wouldn’t like to guess the price I might need a sit down first. However whether a flank drive provides greater drive on the bolt head matters not if the bolt is properly seized. It will shear if properly stuck. I managed to get a steel thread out of an old brass pump that someone dropped off had been siezed in there 31 years. Local engineering shop said impossible. 5 minutes. Weld a bolt inside the broken thread. Induction heat to cherry red, douse with water until cold. Impact gun straight off. Job done.
You're obviously a master at removing problem bolts. Last time I sheared a bolt it was in a flywheel and the job rapidly worsened when drilling and tappingGassing Station | Home Mechanics | Top of Page | What's New | My Stuff