**** happens, but not me again! Drill bit advice please

[It'sNotWorthComplaining!]

I'm trying to remove 2 broken exhaust flange studs, Access underneath is not a problem, I've tried drilling and using an easy out, but after having one break years ago, I decided not to force it in case.
So I decided to drill the stud out, all was going well until I noticed a red Glow ( had it going too fast) and the bit end melted.
So now I have the problem where I can't drill it out as the drill bit steel is hard and the other drill bit goes blunt.

IS there a special drill bit that will drill out hard steel?
I'm pulling out the 2 strands of hair I have left on my head

[It'sNotWorthComplaining!]

I came across this, might see if I can acquire one.


Solid Carbide Drill-bit

Now this is a beast. It will drill and cut into a screw and stud extractor (also known as an "easy out") — an extractor tool for a broken stud/bolt, and these are made from quite hard steel in their own right.
There is also a fair chance that it could cut into any of the above drill-bits, if you could keep it on centre.

[Killer]

If you get hold of a masonary bit and sharpen it like a standard twist drill it should do the job. Only problem is you need the correct type of grinding wheel (green wheel) to sharpen them.

Cheers, Mick.

[GuyG]

I believe you can get a reverse drill bit, so in addition to drilling it out its trying to undo it also

[It'sNotWorthComplaining!]

I believe you can get a reverse drill bit, so in addition to drilling it out its trying to undo it also

It didn't beak in the hole, it melted itself in there, so the bottom of the hole is tipped with hard metal.

[nice1guv]

A carbide drill bit should do it, and most places should have them.

If not then my next step would be a diamond tipped drill bit, but they are expensive and hard to get.

[incisor]

not good juju

carbide tip, medium->slowish speed and some cutting compound or water to keep the heat down...

trick with carbide is not to let it chatter...

[Bigbjorn]

Sounds like you were using a blunt drill to start with. If you had used a reverse helix drill first you most likely would have unwound the offending stud. A tungsten carbide inserted drill or solid TC drill will do the job. Get a stub drill or a straight flute drill. You are less likely to break a stub drill. The grade of carbide used in masonry drills is not the same as used in hard steels but if sharpened correctly to 135 degree twist drill geometry on a silicon carbide or diamond wheel will do but will likely be stuffed afterwards. If available I would use a straight shank, straight flute TC inserted die drill. These normally use C2 carbide. go to a good engineers supplier.

[johnclv]

All suggestions are good especially the reverse drill bit

If you can leave your manifold on and use it as a guide to drill out the stud ( and then use a helicoil ) that works well

After my first bad experiience with snapping of a easyout, the next time I snapped a stud I found a guy in the yellow pages ( brisbane ) who does that for a job. Thats all he does, remove and replace studs.

Came out to my place and for $100 removed and replaced all my studs. He had all the gear and it was done in 15 mins ( I removed and replace the manifold myself etc )

For that price I could not be bothered doing myself

Just remember ( as I am sure you know anyway ) when drilling steel - slow and easy is the way to go. High speed and pressure is one way to killl drillbit

My Disco broke a stud or two on a yearly basis. POS!!

[rijidij]

A mate of mine had a similar problem on a prime mover, I think. He ended up buying a cobalt drill bit. It was then like drilling through butter apparently.

"8% Cobalt Content.

Suitable For Drilling Into High Alloy Content Steel and Metals with Tensile Strengths over 1000N/MM2."

Cheers, Murray