Exhaust bolt

[klektermaniac]

Hello All,
Oh Bother, and it was all going so well!! I have broken off a new stainless steel bolt in the exhaust port on the cylinder block.
I have tried HSS and Cobalt drills which hardly marked it. Someone in the Goldie club suggested a masonry drill so I tried and it was the most successful, but will take forever.
Are there any drills of harder material I could use? Is there such a thing as a diamond drill? I am looking at approx. 3mm drill size to start with, and as I am drilling slightly uphill it is very difficult to cool/lubricate while drilling.
Any suggestions?
RogerH.

[PaulD738]

When you get the pilot hole drilled try a slightly bigger left hand drill and if your lucky the stud will wind out.

[stevewharton]

When you get the pilot hole drilled try a slightly bigger left hand drill and if your lucky the stud will wind out.

Exactly what I did when I broke the same bolt in the same place. Bought a set of left hand drills off ebay and it came out easy, my tip is keep the drill speed very slow or you'll harden the broken bolt (if you haven't already) and use WD40 on the drill.

[Kettletimes3]

A decent cobalt should do the job,
Unless as Steve said it’s already hardened it.
Do you have any stud protruding if so get a nut welded to it.

[klektermaniac]

No protrusion at all - that would be too easy!! I will persevere and keep fingers crossed.

[PaulD738]

Give yourself a start with a center punch and if you have a center drill use that to break through the hard surface you’ve created. Should be ok then.