Just a bit of info that might help but sorry if I'm teaching u to suck eggs. A couple of exhaust studs sheared on my 4dx and when I was drilling them out the drill bit snapped and was stuck in the hold. Luckily I'd got my boss to order some stellite drill bits a few weeks ago, what a coincidence lol. Anyway I drilled the broken drill bit out with no problems. They're available from Cromwell tools it's online or they have a few shops nationwide. They're £28 for the 5mm one or you can get upto 6mm and can buy separately or as a set. I know it's dear but could save a lot on paying someone else to do it.

Is sellite better than cobalt then ???

I have a difficult one at the moment. I'm putting back a starter motor and gears to an engine, the sprag clutch oil hole was welded closed so needs drilling out and f*** me isn't that an arse of a job.

They use Stellite to rebuild camshafts Very hard.

Yeah Boris it's solid carbide, it goes thru drills and taps like butter only thing is it needs a fast speed and with it being so hard it's obviously brittle bit it'll fly thru weld.

Ok. Well I need the flexi extension to turn up first, then I can try with the cobalt bits. If that doesn't work I'll be on for one of these

Success.
With the flexi extension use my drill rather than the dremel. Took a bit of time but its through.
Now i can put the clutch back and install the sprag clutch and gears.

Nice one. I think nearly every bolt on mines been seized lol. But I stripped an 89 tdr250 for my brother in law to ship over to Australia for him and not a single seized one

Yeah, but the TDR is a 2 stroke and they use oil

True lol