Broken bolt

[Loose Nut Buster]

In an attempt to drill out to remove it I ended up off center, its about 5/16 but in metric, the hole I drilled is just over 1/8"
Any suggestions on trying to center it so I can drill n tap it. I've tried heat, freeze off along with an EZ out without any luck, it broke off flush
I read somewhere that a carbide drill would work going very slow but am at a loss to keep it centered.
To make it worse is that I'll be doing this directly above and into my tractor transmission with metal shavings entering into it I'm sure.
All suggestions will be greatly appreciated.
Thanks in advance.

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[NUTTSGT]

Do you have a mig welder ?

 

[Loose Nut Buster]

I do

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[asallwey]

A carbide drill will drill it. However, they don't like to be bent, or have sideways pressure, and will break. I assume you don't have a welder, too bad. About all you can do is continue drilling with a larger drill. Keep going bigger until you almost touch the threads on the close side. Then take a pick, or make one, and carefully try to unwind the bolt and/or pick out pieces, etc. Grease on the drill may keep it from falling in the trans. If you can't get it all out, **** it up as a bad effort and take it to a shop, they can deal with it.

 

[Loose Nut Buster]

I do have a Miller Matic mig w/argon

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[NETexas]

Weld a bolt to the top of broke bolt. Also a good magnet to catch the shavings.


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[NUTTSGT]

I do

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Weld a nut over the broken bolt.

Many videos on Youtube, this is just one.

 

[Wrench97]

What metal in the bolt screwed into?

If aluminum welding a nut on is a lot easier since the weld won't stick, if it's steel you may end up welding the nut to the base metal......................

 

[Loose Nut Buster]

Thanks for the help you all have offered.
When the weather improves curgently 8" of snow and (turf tires) with more on the way, possibly spring i will post my results.
Between enlarging the drilled hole to using the grease or magnet to contain the chips, I'll reacess my situation n give it a shot.
Thanks to all n a Merry Christmas to ya! And stay safe! Thanks again.
This is it in better weather.


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[Loose Nut Buster]

Not real sure on metal type, its the trans shift cover, I'll put a magnet to it but sure it's a cast of some sort.

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[rustrunner]

The bolt is probably steel. As answered above, weld a nut to the bolt.

 

[My Old Tools]

Next time use a left hand drill bit. They will generally back the bolt out as you drill it.

 

[TractorJeff]

Assuming the bolt is broke off flush, weld a washer to the bolt. This minimizes hitting the casting, then weld a nut to the washer. Transmission is probably Cast Iron.
If you go the option of drilling till almost touching the threads, then an old school Cape Chisel and a lot of patience will eventually turn the bolt out.
Personally, I use the washer trick quite often. They will pull a part, weld another on. The repeated heat cycles will allow for expansion and contraction of the bolt.

 

[asallwey]

If you are going to use your welder, don't drill out the bolt any more. You want the most metal possible to weld to. As stated, use a washer and a nut. Then after you weld them on, give them a couple of moments to cool slightly, then stick paraffin wax or a candle on it to melt (should sizzle). Once the wax has cooled it is ready to apply a wrench, not before.

 

[RoninB4]

Agree with carbide being very brittle and likely to shatter during free-hand drilling. Carbide drills, especially that small, should only be used in a drill press or vertical mill. Hope you've not broken that EZ-Out in the hole, they're very hard and are difficult to drill out even with carbide. The welding tips may work, as a machinist I always resort to methods that cut metal. If the broken bolt/stud has rusted in it may be difficult to remove by any other method than drilling, only you will know this. Soak the broken bolt in PB Blaster or another suitable fluid for several days to help loosen the rust. If it still won't budge, is it possible to simply drill and tap to the next larger size fastener? To keep chips out of the ****** either use the grease tip or a shop vac with the nozzle held real close to the hole, put up some cardboard barriers to contain the chips. That's what I do at the shop.

 

[matt_i]

Just a few more ideas.

Can you remove the rest of the trans shift cover so that you have a chance to catch the metal that might be going below, or at least figure out if the cast boss is a blind hole and you don't end up drilling thru the bottom of the boss....

You said heat. The only heat I even consider on a broken bolt job is oxyacetylene. Don't even bother with propane as all its going to really cause is a burn when you are impatient and don't let things cool off. You gotta get it a dull orange color and unless its a #2 screw the propane can't do it.

LH drill bits are good if the bolt was broken off in a clean-ish indoor environment without likelihood of corrosion. But once the possibility of rust is likely the root cause of why the bolt broke off then see above: blue wrench.

I strongly prefer this style of extractor for such ops.

https://www.irwin.com/tools/screw-bolt-extractors/straight-flute-screw-extractors-536526-series

Its similar to a 4 flute tap but the advantage is that the extractor will slip and carve out 4 metal chips before it breaks clean off itself. As opposed to the left-hand spiral extractors which just go in tighter and eventually put so much outward radial pressure on the threadform that its actually binding the works.

So you'd heat it to dull orange, tap in the extractor and wiggle back and forth. If nothing happens not to worry, see below. It may take a couple cycles of heating to get it loose.

The advice above to use Gulf/canning/paraffin wax is an excellent one. After heating the works as above, let it cool back until all temperature color is gone, a couple minutes more, then try melting the wax. What you want to see is the wax running with the consistency of water down and around. If the wax is touched and there's a big cloud of smoke its being vaporized and isn't doing its job.

To center your pilot hole back to center, a Dremel or Foredom tool is excellent. They make some diamond coated points which work slowly but are fairly unstoppable in all hardnesses of ferrous materials and don't chatter like a carbide bur can.

https://widgetsupply.com/product/xj...Iy0M1BAXr1NTGaj4qNnhbelN4XydqF6IaAsHGEALw_wcB

https://www.garrettwade.com/diamond...blUPSYUAknIXMmZjFs-lWLraJaATNIzQaAngWEALw_wcB

https://www.foredom.net/product-category/burs-bits-cutters-buffs/diamond-points-discs-files/

 

[Loose Nut Buster]

Thanks fo all for your help suggestions, I've inserted this into my Google keep app and will have to wait until warmer weather to work on it and will repost my results.
Thanks again and wishing all a healthy and prosperous 2021

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