Sheared bolt on my Powermatic 60

[Mike Rother]

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bolt for the table lock handle sheared right off. Bummer. I have the new bolt ordered. Any thoughts on extracting the remnants of this old one? Do those bolt extractor bits work for something like this? Help…

thanks

[Rich Riddle]

Wow. It takes quite a bit of torque to snap that bolt. I use the Rennsteig to remove sheered off bolts. The twisting type bolt extractors never seem to work well. The trick will be drilling down the center of that bolt. With the Rennsteig you simple make the hole and tap in the extractor. It's shaped like an octagon. The Rennsteig has a bolt head on the extractor. If you are going to wrench that bolt that tight, you might consider going to a grade 5 or grade 8 bolt.

Here is what the Rennsteig extractors look like.
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[Bill Adamsen]

Could be worse ... could be a broken drill bit in a broken tap or broken extractor.

I've had limited success with the extractors on steel embedded in cast iron, using heat, penetrating lubricants and patience. It seems to work best when the issue was human error ... over-torquing or snapping off the stud. Definitely worth a try. Put extra effort into trying to get the hole in the center of your bolt so that if it doesn't work alternatives are easier. Don't break the extractor in the hole. It will worsen your day for sure.

This afternoon I drilled out two (broken) bronze bolts and re-threaded the embedded bronze plate. I had tried extractors unsuccessfully. The location was such that I couldn't use heat or lubricants, and I could tell they weren't coming out. I was sure I was going to have to tap and thread up to the next size, and was surprised the threading meshed perfectly with the old thread. Pleasantly shocked - this kind of good mojo is rare! It looks clean enough to stay at the original 1/4". So I guess I'm saying extract, or, worse case ... drill out and rethread or tap and thread.

You might search on Practical Machinist for ideas related to extraction. The folks there all have loads of experience in this area.

[M Toupin]

File or grind the broken end flat. The flat surface is a lot easier to center punch and drill dead center without skittering around. Use a LEFT hand drill bit to drill out for the extractor. About 50% of the time the broken bolt will come out on it's own if you use left hand bits. If not, then go to an extractor but first heat it with a torch and touch some candle wax to it, not red hot, just reasonably hot. You want the wax will be drawn into the threads and help get the broken piece out. Then use the biggest easy-out you can, they are brittle and will break, the larger the easy-out the less likely you'll be to break it.

Ok, so you don't absolutely need a LH drill bit and any size extractor might work, but I prefer to give myself every opportunity to get it right. If you break a drill bit or extractor in there you're going to be in a lot worse situation than you're in now so be careful!

Once you get the broke one out and a new one in, just snug it, it doesn't take much to lock it down. Next time you might not be so lucky and the way will break instead. That will be a disaster.

Mike

[Mike Rother]

Thanks all. Didn't even snug it down that much. Must have seen some harsh times previously. Just ordered the Rennsteig set. Here's hoping. I'll file it down flat, center punch and heat it. MAP gas torch will work? First time for all this...

[Dick Brown]

If you have an arc welder, and if the bolt is not broken off below the surface, place a flat washer that just fits over the broken bolt, weld the hole full making sure you get penetration on the bolt, set a nut over the washer and weld it to the bolt/washer by filling the hole, once again making sure you get weld onto the nut, bolt and washer. Nut can be larger than the bolt so it is easier to get welded to the bolt/washer if you want. Weld and let it cool. This gives you the nut to back the bolt out with, heats the bolt to help break it loose from rust, etc. Nice part of this is if you don't get it the first time, you get more chances. Do the welds thing again, or you can still grind off flat, drill and e.z.out or re-tap the hole. Needless to say, use mild steel welding rod.