I have to drill a sheared bolt out of a John Deere tractor 3 point hitch. It appears to be a very tough steel, as standard bits don't bite.

Will a carbide steel drilling set get this done for me? I've built a guide bolt which threads into the hole where the bolt is recessed to drill the center without wandering, but I'm just not getting any cutting with a brand new steel bit and cutting fluid.

Damned thing is recessed, and in a position which requires a 90 degree drill adaptor which limits how much pressure I can put on it.

Tomorrow will be day three on this little bastard, and I'm getting pissy. It's not in a position where I can weld to it and use that method either, unless I drill the guide bolt out to about 1/4 inch, and try to weld it with wire feed from the inside cavity of the drilled guide bolt. Not something that appeals, as the opportunity for things to go sideways seem pretty high.

If I can't extract this thing, I have to remove the seat, hitch, rocker shaft housing, and buy a new rocker shaft which is a $647 dollar part not counting consumables and time.

Worst part of this is that it broke because it was over-torqued when installed and cracked. Water got to it and it eventually failed due to a rust through. Of course, the tractor is 10 years old now, and well past warranty.

You're just wasting your time with regular high-speed steel. Carbide bits can work on virtually any hardened steel.

It's usually worth buying a left-hand drill for removing broken bolts. The unscrewing force while drilling left-hand usually aids in the loosening of the bolt. A lefty cobalt steel drill will likely do the job. A carbide drill will be more money, but will cut your bolt, although you might balk at the price of a carbide left-hand drill.

TiN coated Carbide if you can.

https://www.mcmaster.com/produ...s=carbide+drill+bits

Not left handed but could get you started for a an extractor.

I’d soak it in Kroil and maybe try using a can of compressed air to “freeze” shock it.

I hate(d) drilling holes. You need a cobalt drill, properly sharpened, and preferably a left-handed one. Center-punch the bolt as best as possible. This can be difficult as A, the surface of the broken bolt is irregular, B, bolts are harder than most punches, and C, you don't always have room to swing the hammer for a good blow. The most important thing is technique. Press hard and turn slowly, just enough to turn smoothly without stalling. If you turn the drill too fast, it not only doesn't do anything, but dulls quickly. Air drills suck for this. Even a fancy Snap-on one I had had only two speeds - zero and full rpm. Good luck trying to start the hole without skating off. I had to put air regulators on them to slow them down, but this had its own problems. An electric drill is easier to modulate the speed. Do everything right, and the shavings will come out as two continuous spirals.

Staying centered is not a problem. I center drilled a bolt of the same size and threaded it into the hole to act as a guide. I just need something hard enough to drill this damned bolt.

Will try carbide tomorrow after a trip to Lowes.

I have left hand twist, but not in carbide or cobalt.

quote:

Damned thing is recessed, and in a position which requires a 90 degree drill adaptor which limits how much pressure I can put on it.

That right there is killing you.

Is there any way at all you can take the workpiece apart or take things off of it so you can get a normal drill in there? If this is feasible, is the offending part small enough to fit on a drill press table?

quote:

Originally posted by ArtieS:
Staying centered is not a problem. I center drilled a bolt of the same size and threaded it into the hole to act as a guide. I just need something hard enough to drill this damned bolt.

Will try carbide tomorrow after a trip to Lowes.

I have left hand twist, but not in carbide or cobalt.

This is a good start, If I was doing it, I'd buy a carbide drill the same size as your guide and one of your left-hand drills. Then use the guide and carbide to get a good start on the broken bolt, then go into it with the lefty. The bolt isn't too hard for HSS. Even a Grade 8 is likely just heat-treated 4140 or 4340. Slower RPMs and cutting oil will help.

I estimate 3 hrs. To get the part out, given how much tractor I would have to remove. I'm not sure the removed assembly would fit in a drill press vise.

That's next if this doesn't work.

I have noticed that using a guide that the chips have no where to go, so your going on the drill chips while trying to cut the broken bolt, need to keep the guide hole flushed out.

For the remover, I really like the non tapered style. Drill the center hole, tap in a straight fluted shaft, then slip the special nut over the fluted shaft.

quote:

Originally posted by ArtieS:
I estimate 3 hrs. To get the part out, given how much tractor I would have to remove. I'm not sure the removed assembly would fit in a drill press vise.

That's next if this doesn't work.

Heat the living daylights out of the broken off bolt and spray penetrating lube in there for a few heat cycles, and use a really good left handed carbide bit with oil.

What I have done in the past is to use ferric chloride on hardened steel screws/bolts. It is PCB etchant. Was available at Radio Shack a number of years ago but can be searched and ordered on-line. I just put a few drops on the screw and waited overnight. It loosened up enough that I could actually unscrew it.

On another note...If you are able to get a carbide drill bit remember that they are brittle and cannot take any side to side movement. It will break. I only use them in a drill press.

quote:

Originally posted by C L Wilkins:
On another note...If you are able to get a carbide drill bit remember that they are brittle and cannot take any side to side movement. It will break. I only use them in a drill press.

Because of this I’d try a cobalt drill first. Less likely to break, cheaper and has usually worked when drilling hard materials. Have had good results using Dewalt’s brand and they’re not too difficult to find (usually locally but Amazon has them if that fails).

I got the bastard! Carbide bit put enough of a dimple in it for the left hand drill teeth on the larger size extractor to bite and back it out!

Victory!

You got lucky there!!!!!!!!!

Nice!

Well done, and in this toasty summer heat even more impressive

Don't forget never-seize on the new one.

Regarding Cobalt drill bits, M42 Cobalt bits are better than lesser grades of Cobalt drill bits. I need some M42 bits for a small project, and found them at Northern Tool believe it or not, and the price was reasonable. You won't find M42 grade bits home depot or lowes.