Arrgh. Have what's left of a Grade 8 bolt,flush with a steel plate. Any ideas how to get it out? Can't get to the back of it( it's flush too). 5/8" bolt in 3/4" plate. All ideas, short of dynamite, welcomed ! Jay
Carefully centerpunch the bolt. Drill a hole through the bolt. Pound an Easyout into the bolt and remove. If the stub is not in a blind hole you may luck out and have the drill bit catch in the stub and screw it through the plate.
Soak it in Kroil an do a few heat cycles then try an ezout or drill it out with a left hand drill very sharp and you might snag the thing and walk it out. You might try a center punch and hammer and walk it out too. The trick is to figure out why it is siezed and why it broke...fix that!
|Arrgh. Have what's left of a Grade 8 bolt,flush with a steel plate. Any |ideas how to get it out? Can't get to the back of it( it's flush too). 5/8" |bolt in 3/4" plate. |All ideas, short of dynamite, welcomed ! |Jay
But try the Ez first. You can also punch out many such. A prick punch that will bite on the edge of the bolt material, if hammered (sharp blow, then assess and try again, and again) in a counter-clockwise direction (RH thread), "may" back it out. FM (of limited mechanical vocabulary)
JR North wrote: (clip)doubtful it could be accurately drilled with a hand-held drill motor (clip) ^^^^^^^^^^^^ I am not as pessimistic as you. I have done this, without the precision, and what happens is that when the hole reaches the threads on the near side, you will very likely get a thin easily removed shell of the former threads, which comes out by itself, or is easily removed with a pick.
Worst case scenario--you mess up the threads, so you make your final drill size a Helicoil bit, and go from there.
I also like the idea of welding on a thin nut. You might even try welding on a flat lever with a hole in it, and then using it as the removal tool. I would make the hole a tad smaller than the thread diameter, and countersink it for easier access by the welding rod.
BTW, do we know whether the thread is siezed? Maybe a Dremel type tool could be used to cut a screwdriver slot, and just walk it out.
When Junior got his first car, the rear plate was attached with sheet metal screws into a clip on speed nut in one hole and into the hole plug in another. He insisted that the twisted off 6mm bolt had to come out of the nut-sert, so I grabbed the trusty hand drill and a couple bits. Would you believe, first try the thread spiral wound onto the bit when I broke through and I didn't even need to clean up. Junior was properly impressed. Gerry :-)} London, Canada
Easy outs are always worth a try, and I usually have success with them unless the bolt broke because it seized or bottomed out in the hole. If you're drilling the bolt anyway, might as well try the easy out - making sure not to twist so hard that it snaps.
One of the problems with easy outs is that they can expand the broken bolt. The trick here is not to start with a hole for the largest size easy out that will fit the bolt. Start with a smaller size first, so that the smaller hole and thicker sidewalls won't expand the broken piece. Tap it in gently - don't bang it in so hard that it wedges the bolt into the hole. If it slips, tap a little harder.
Snap On, I believe, sells or used to sell a set of easy outs that had straight non-tapered splines, claiming that they would cut when driven in but would not expand the bolt. Makes sense to me, but I never tried them.
wws wrote: What's the problem with welding another bolt to it? (clip) ^^^^^^^^^^^^ It would be very hard to butt the end of a bolt against the flush, broken end, and make the weld, without sticking it to the metal around it.
Think about it for a moment - how much precision is *really* needed?
The difference between the crests of the female threads, and the root of the male threads is what counts here, and that number is typically at least five thou. For a larger fastener like that it may be ten.
Then consider how much effective 'wall' can be broken out - if there were another ten thou of metal that had to be broken though to make the 'helicoil' of leftover threads unwind, that's a doable situation.
Finally, the reason most fasteners sieze in place is from rust. Rust makes the fastener *bigger*, rust has a larger volume than the steel that it used to be. So the bolt is oversized and that jams it in the threads. Relieve most of the radial force by hogging out the center of the bolt and often the remaining bit just unscrews.
Really all you need to do is get +/- 0.015 accuracy and the hole will work fine. I've done this hundreds of times over the years.
The real trouble happens when a drill snaps off in the fastener as it's being drilled. This sometimes occurs when it's a blind stud, and the drill breaks through into the pocket underneath. Using a larger than normal pilot drill size helps prevent that.
Then the ultimate CF is when the E-Z out snaps off in the bolt. Those things are brittle and hard. They also tend to cam the fastener open more, and bind it in harder.
================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================
JMartin957 wrote: (clip) Snap On, I believe, sells or used to sell a set of easy outs that had straight non-tapered splines, claiming that they would cut when driven in but would not expand the bolt. Makes sense to me, but I never tried them. ^^^^^^^^^^^^^ I was lucky enough to find a set at a flea market once, or I could not have afforded them. They really work. Each size comes with its own drill bit, and a special nut, which slips over the spline, which gives you much better torque and less chance of slipping that the usual tapered easy-out. If you are really stuck, I would say the price would be worth it.