Spark Erosion

[Chris Hebden]

Has anyone had experiance with this process? I have got a broken bolt in the O/S/R trailing arm so tried to drill it but have got 2 drill bits stuck in it (yes 2, i'm a glutten for punishment)

Spoke to an engineering firm and they said that this is the only way to get the drill bits out, anyone got any other ideas that may be helpful as i am really stuck now! Cheers

[RichR]

Depends on what the drill bits were made off. If they're fairly cheap HSS ones, you may well be able to drill them out with cobalt drill bits. I have successfully done this a few times.

If you do decide to lash out on expensive bits to drill out the cheap ones, make sure you run them at the correct speed (generally a lot slower than you think), with adequate lubrication and ideally in a drill press rather than hand held. Saves you swearing when you break one....

Don't forget to weigh up the cost of getting the broken bolt out of a component against what a second hand component would cost. It might be cheaper and easier just to take an angle grinder to the offending item and replace it.

[Chris Hebden]

Depends on what the drill bits were made off. If they're fairly cheap HSS ones, you may well be able to drill them out with cobalt drill bits. I have successfully done this a few times.

If you do decide to lash out on expensive bits to drill out the cheap ones, make sure you run them at the correct speed (generally a lot slower than you think), with adequate lubrication and ideally in a drill press rather than hand held. Saves you swearing when you break one....

Don't forget to weigh up the cost of getting the broken bolt out of a component against what a second hand component would cost. It might be cheaper and easier just to take an angle grinder to the offending item and replace it.

Thanks for the info Rich, the drill bits i would have thought were cheap ones to be honest.

I have only the option off hand held drilling as i dont have a drill press unfortunately! As the bolt is all the way through, would i be able to do the drilling from the other side to try and remove the broken bits? Or would this cause more trouble do you think?

Well the reason i am looking into the drillng out option at the minute is because i dont know what sort of price a second hand torsion bar and traling arms would be, or just the trailing arm if thats poss? Any ideas? Cheers

[Brigsy]

If you remove the disc can you get away with a pair of stilsons/molegrips on the remaining part of the thread? Ive just removed a snapped bolt in my front hub using the same method.

[Chris Hebden]

No i tried that mate, but couldnt shift it.

[chris5sco]

First post!

if you have access to a mig welder weld a nut onto the remaining thread the heat from the weld should loosen the rest of the bolt up and that way you'll have a something to put a socket on aswell. do this all the time in work and works pretty well.:)

[Chris Hebden]

First post!

if you have access to a mig welder weld a nut onto the remaining thread the heat from the weld should loosen the rest of the bolt up and that way you'll have a something to put a socket on aswell. do this all the time in work and works pretty well.:)

Sounds like a blooming good idea mate! BUT dont have a welder! Thanks though

[5teve L]

The welding thing works, i had a stubborn bolt before & had to do this then i rounded it :)

[Chris Hebden]

Well after a week without the 5 i finally got it back together! Got an axel and threw it on their this morning worked out a treat!! See classified feed back for the big thanks to the people that got me back on the road again! :)