Drilling hardened steel - drill supplier

Hi

Anyone know anyone in the UK that supplies those drills that can drill through hardened steel? I have seen these at ME exhibitions drilling through old files etc. For the life of me I can't find a supplier other than USA or Australia.

A friend of mine tried to use a stud removal tool to remove a broken stud, the type where you drill a hole in the broken stud the insert the stud removal tool.

Unfortunately he has broken the stud removal tool so is now in a worse situation.

It's on an engine exhaust manifold so spark erosion is not possible without removing the engine.

I have suggested that a carbide or diamond burr with a die grinder might be possible if time consuming

Appreciate any other suggestions, the stud removal tool is round 6 to 8mm.

Many thanks

Nigel

Edited By tractionengine42 on 09/04/2014 17:15:53

If you can get the pressure until its red hot a Stelite drill
Nobby

Hi Nigel,
I have seen tungsten carbide drills advertised some time ago on one of the shopping channels that claim to drill though hardened steel. On another thread someone suggested re grinding masonry drills so they have a proper cutting edge. I have not tried this but I think it might work.
I have just had a look on Ebay and found these. They may work

Les.

I try where ever possible to use left hand drills (solid carbide) for stud removal, that way you are actually trying to remove the stud rather then screw it further in. Have collected two or three over the years from about 1/8 to 3/8. Were on the face of it expensive but when you take the time energy effort into account not that bad and you get to use them again if your careful.

Surely, a Cobalt type drill will drill an Exhaust Manifold stud? Stellite and the like are quite brittle and go of vertical or have a wobble and that's the end of an expensive drill. I have had Vehicle Engineers use Loctite 290 on studs and cursed them roundly. Had to heat them up with Acetyline torch to kill the loctite and get the broken studs out. Initially on the broken stud I would drill a small hole and then squirt in some penetrating oil and leave overnight. Then go up through the drill sizes until you break the threads and you can then wind out the remainder. I often have to drill out threads as small as M2, M3 and M4. on Instruments and the casting is Alu/mix, sometimes very difficult.

Clive

Carbide or Cobalt drills should have no difficulty drilling into any bolt or stud. The problem you have is that you are very unlikely to succeed because you wont be able to apply enough pressure to make the drill cut. At the right speed in a drilling machine its straightforward, hand held in an engine bay will lead to frustration.

Diamond burr at high speed combined with patience is a better plan.

You say the part in question is the exhaust manifold, surely that can be taken off and done on the bench?

On re-reading your post I think I now understand that it is the 'stud remover' that is stuck in the stud, That will be harder and more brittle than any stud so back to the diamond burr.

Ian P

I only have experience with very small diameter carbide drills, but they break very easily if you use them in a hand tool, if that happens you have an even harder part in the stud. I would first try a small diameter masonry drill with altered cutting edge to make a pilot hole. Niko.

I have in the past, Tig welded onto the top of a broken stud in order to build it up enough to get hold of it with a pair of mole grips, the extractor will require you to soak the heat into it with min amperage, then build up from there, it takes a lot of care and a steady hand, it really depends if you have room, and how far into a blind hole your working 3 or 4mm below the surface on an M8 stud is possible but not easy, and the heat will loosen the stud during the weld........if your lucky

Hi, just like Involute Curve has said i have built up brocken off studs with weld, in fact it's always my first choice, but what I do normally is build up enough of a pip to then weld a nut on so a spanner can be used rather than grips, Two or three attemps have to be done some times. I done this to get my old glow plugs out of my Astra engine a while ago. A few photos can be seen here **LINK**

Regards Nick.

As Graham/Les said Masonry drill bits can be used but the tips have to be sharpened and sometimes the rake angle changed so as to get the drill to make the initial bite.

The flow of coolant is also important

Not sure it would work in this instance as you need to apply a bit of force to get first bite and then apply constant pressure.Probably not possible in what you are trying to do due to the nature of what you are drilling and access to it.

Possibly get one of those right angle drill attachments for the job.

Clive

Hi

Thanks everyone for you help and suggestions. Some good reference for future similar problems. I was very surprised to find left hand drills on ebay, so a few sizes are on my wish as 'will be useful someday' tool kit accessories.

I visited my friend today to have a look, the broken stud and stud extraction tool is in a cylinder head where the exhaust manifold bolts on. He doesn't want to take the cylinder head off to try and fix the problem. Access is tight so it's difficult to get weight onto a pistol drill for drilling hardened steel using a modified masonry or tungsten drill.

We decided it would be best to take it gently and get a small diamond burr and 5mm diamond coated core drill. The plan is to use the diamond burr to flatten and dimple the end of the broken stud/stud extractor. It's hoped that said dimple will help centralise the core drill which will follow.

My friend has also bought a set Frhei drill bits for drilling hardened steel in case they may be useful at some future date.

Cheers

Nigel

Tracy Tools sell good quality Left Hand drills at very competitive pricing.

graham.

Tracy Tools sell good quality Left Hand drills at very competitive pricing.

graham.

This is the slickest method that I have found. I have used it several times with my Lincoln 180 Mig Welder; mostly for removing rounded oil pan bolts and broken exhaust manifold studs from equipment belonging to friends and neighbors. Why they persist on using adjustable or open end spanners (wrenches or knuckle dusters to Canadian Army mechanics) is beyond me.

The following is a link to an excellent description of the process.

**LINK**

Bill

depending on how deep in the broken stud remover is, you may be able to shatter it with a punch and pick out the pieces with tweezers, but i think the diamond burr is the most straight forward - even if slow and steady...

-russell

( last lot of stud removers i had were not the standard left hand taper thread style, but square taper with sharpish corners...just drill the stud and hammer in. If (when) they break , theoretically, just a sideways impact loosens enough to allow removal.)

I have a set of Blue Point extractors by Snap On Tools, these are parallel pins with four splines, these are hammered into a hole drilled in the end of the broken stud, a hexagon nut fits over the spline to unscrew the stud. To drill the hole a guide is provided. As the hole is central, it's not to much of a job, if the extractor doesn't work, to drill out to root diameter, and pick out the remaining metal. These extractors don't expand the metal of the stud as an Easyout seems to. Ian S C