How to Get Shell of Drilled-Out Bolt Out of Part

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SteveHGraham
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How to Get Shell of Drilled-Out Bolt Out of Part

Post by SteveHGraham » Mon Jan 12, 2015 5:16 pm

A friend of mine gave me a lawnmower part to fix. It had a bolt stuck in it. The part that was stuck was not threaded. It was 5/8" in diameter and about 2 1/2" long, inside a smooth bore. It should have been a slip fit. There is no rust, but somehow it seized up.

I took it home and tried an impact wrench. It didn't move. I tried a 3-ton press. Nothing. I tried chilling the bolt with dust spray. Still no luck.

I did not want to drill it out, because it's a hard part to mount, and I didn't want to cut into the walls of the bore by accident. Finally, I gave up and got through it using a succession of drills, dulling two or three in the process. The bolt was extremely hard. I had to use very low RPMs.

I ended up going all the way through with a 1/2" bit. Then I tried broaching a slit down the inside of the remaining shell so it would lose its integrity. The broach I made is having a very hard time cutting this crap. I then bored it so there is maybe .010" of metal remaining inside the bore. I am reluctant to keep boring because I don't want to cut into the bore itself.

I had to bore it on the mill because the part is too long to chuck in the lathe. I could do it if I took the gap out, but I am reluctant to mess with that because I have read stories about people having a hard time getting their gaps back in correctly.

Any ideas? I don't have a hydraulic press.
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ronm
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by ronm » Mon Jan 12, 2015 6:25 pm

What is the part made of? You can heat the remains of the bolt red & let it cool, then soak it with loose juice...expansion & contraction is your friend. If the part is aluminum or potmetal, you have to be careful heating it. Thing to remember about seized parts is they didn't get that way overnight, so they might not come loose instantly...maybe heat & soak more than once.
If you can get that last .010 & break the wall of the bolt, it will collapse a lot easier.

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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by OlderNewbie » Mon Jan 12, 2015 6:49 pm

Usually I keep enlarging the hole until it *just* breaks through the shell, which is always on one side, and then pick the shell out. As the lion's share of the bore is undisturbed I have yet to have to bore a part out for a bushing. Alternatively, if the shell is thin, I'll drive a pointed punch between the two parts to collapse the shell if there is room.

Whether either is "right" or not, or right for your situation, who knows?

John

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SteveHGraham
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by SteveHGraham » Mon Jan 12, 2015 7:39 pm

The part is steel. This is really annoying.
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SteveHGraham
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by SteveHGraham » Mon Jan 12, 2015 8:51 pm

I'm at the point now where it's starting to crumble on one side, but it's still stuck to the bore, as if it were welded. I heated it to see if some genius put Loctite on it in the past, but it wouldn't move.
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SteveHGraham
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by SteveHGraham » Mon Jan 12, 2015 8:52 pm

I can go in with a Silver & Deming bit and remove the remainder of the crud, but I'm afraid it will cut the original metal and leave the bolt remnant, so the bore will be off center.
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GlennW
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by GlennW » Mon Jan 12, 2015 8:57 pm

Too late now, but rather than through drilling, leave about 1/8"-1/4" in the bottom. That way you thin the wall quite a bit and it will punch right out as removing the majority of the stock has relieved the tension on the walls.
Glenn

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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by OlderNewbie » Mon Jan 12, 2015 9:15 pm

Glenn Wegman wrote:Too late now, but rather than through drilling, leave about 1/8"-1/4" in the bottom. That way you thin the wall quite a bit and it will punch right out as removing the majority of the stock has relieved the tension on the walls.
...and, come to think of it, that's how you (well, I, at least) remove valve guides from cylinder heads. They're a press fit and can be dissimilar metals, and likely to gall (particularly in aluminum) if pressed or hammered out without relieving the wall stress this way first. It works well and usually they can be tapped out with a few sharp raps.

But you can only start from where you are. It's sort of hard to turn back the clock. How critical is the bore center? It's a lawn mower...what *is* the part, anyway?

John

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GlennW
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by GlennW » Mon Jan 12, 2015 9:20 pm

OlderNewbie wrote:But you can only start from where you are. It's sort of hard to turn back the clock.
Agreed.

It may save someone from getting to this point to begin with!

I take the same route that you explained from this point though. Bore in small increments until you break through the wall.
Glenn

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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by John Evans » Mon Jan 12, 2015 10:31 pm

It's in the mill right ? You got the boring head setup and are boring? If so back off the dia. on the boring head and offset the mill table one direction and bore till you break through in one spot. Or if you have a long enough end mill smaller than the present hole use that to break through in one spot. A small nick in one side of the bore won't be a issue.
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Rich_Carlstedt
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by Rich_Carlstedt » Mon Jan 12, 2015 10:48 pm

Do you have a 5/8" tap ?
In the past, running into a similar case, I have used a tap to grip the sleeve
and break the sleeve loose.
The tap will not cut the bore

Rich

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SteveHGraham
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Re: How to Get Shell of Drilled-Out Bolt Out of Part

Post by SteveHGraham » Mon Jan 12, 2015 10:53 pm

The remaining metal is glued fast to the bore. It won't even peel off. It's like it's welded in there. Turning it with a tap won't work.

Because of the geometry of the part, I could not really get in there to make a pocket and then use the press, but the press isn't big enough anyway, so it wouldn't have mattered. It would not move the metal once it was completely hollowed out.
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