Drill & tap help needed

[letmetalktomark]

Morning All,

I managed to snap a bolt holding on the brace of my beloved Z4 forks the remainder of the bolt is still in the leg.

I have tried cutting a slot in the top of the remaining bolt to aid removal but sadly its a no go.

I think the only option is to drill out the bolt and re tap the thread.

Could anyone help with this?

Cheers,

MArk

 

[hamster]

I would try a stud extractor (also known as an "easy out") which screws anticlockwise into the remains of the bolt. Obviously you have to drill a hole for it first.

Another thing that worked for me was to drill a hole and then hammer in a Torx bit - I chamfered the tip of the bit a little to help it go in.

Clearly the other thing to do first is to loosen up the stud a little - heat would be a good idea and then a good pickling in Plus-Gas.

 

[cyfa2809]

where it snapped
did it leave a lip?
if so, get a screwdriver on the lip and undo it with a screwdriver/hammer combo

 

[letmetalktomark]

where it snapped
did it leave a lip?
if so, get a screwdriver on the lip and undo it with a screwdriver/hammer combo

Sadly not :-(

 

[cyfa2809]

try it anyway??
see if you can get a bit of purchase with the screwdriver

 

[sylus]

I pic may help with best advice, but yes personally I would drill a pilot hole slowly and carefully and use an extractor

 

[weeman_mtb]

I pic may help with best advice, but yes personally I would drill a pilot hole slowly and carefully and use an extractor

Grind the drill you are going to use as the pilot backwards and run the drill in reverse. That way if it snatches it might well undo the bolt, if it just drills you've still got your pilot hole to use an extractor.

I've had success with this method at work many times.

 

[dyna-ti]

On the retapping idea-
The holes on the brace are blind holes and need a different tap from the usual tapered one.
You may well find the tapered section is fully in the hole and the recutting threads havent engaged yet :?

Pic :?

 

[letmetalktomark]

Will get a pic up shortly

Thanks gents