Fixing an oversized hole?

12 thou? how thick is a beer can?

split your part and rebore .020 saw cut will make it smaller.

Bore it out 30 over and put in a slotted bushing. You don't need to slot the bushing over its entire length. As you have found out, end mills do not cut to size. Use a boring bar to do precision hole sizing, or drill and ream.

Jim

Slit it, lay on some weld in the bore, or get it metal sprayed, clamp the two halves together with an appropriate shim (the thickness of the saw cut) between them and BORE it (correctly) this time.

All of which may be "gilding a turd". I'd try it as it is and see whether it clamps enough to do the job, "Pretty is as prety does", 'yknow.

Happy Holidays,

jeff

If you are going to cut it in half and use two bolts to clamp just cut it apart and rebore. If you were just going to do a slit on one side, it will still work if you can take up an extra .040" in your clamp arrangement. If you just clamp up once, use a beer can for shim stock.

JB weld w> I was trying to put a 1.125" hole through a piece of steel that's 1.5"

Unless there is something I don't understand, scrap the part and start over. Jim

Just silver solder in a sleve "Bruno" skrev i melding news: snipped-for-privacy@4ax.com...

Before I would attempt any repair I would slit it and try it as is. .012 is not much to squeeze and still get a good clamping. You might also cut your slit at a slight angle and drill your clamping screw holes perpendicular to the slit. This will reduce the ID of your clamp in two directions as the slit will give you a little sideways slip also.

"Unless there is something I don't understand, scrap the part and start over. Jim"

I agree. Start over & do your finish id in the lathe. It will probably take less time & aggravation to make over than to fix it.

||I was trying to put a 1.125" hole through a piece of steel that's 1.5" ||x 2.5" x 1". I was using a mill and the only 1 1/8" cutter that the ||shop I was in had. It made a really lousy rough cut that's also about ||.012" oversized. This piece needs to be split to clamp down tight on a ||1 1/8" post. || ||Anyone have a suggestion for how to fix it up? || ||I've never used JB Weld... would it work to line the hole with that ||and then bore it to 1 1/8"? I've made a jig so I could put the piece ||on the faceplate of the lathe to bore it there; I may not have access ||to a mill for quite a while now, so a lathe approach is best. || ||I was also thinking about a sleeve, but I'm not sure if there is ||enough room to bore it out to fit a sleeve in there. If I did, what ||size OD on the sleeve would work out? Or should I say, how thin could ||the sleeve wall be? || ||Last resort is to smooth the hole out as well as possible and then ||slit it much wider than I had planned, but that's not the best way. || ||Thanks. ||-Bruno

Texas Parts Guy

JB "Weld" (*ugh*) is just epoxy glue, with a dishonest and deceptive trademark.

Yeah. I was looking for a filler a while ago and asked the store guy what would work... he suggested, hmm... JB weld. How strong is it? Strong as steel... But uh, the package says only two thousand PSI? Yep, strong as steel!...

Tim

-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

Knurl the bore. This will make the effective ID smaller. Ideally the knurl will make the ID smaller than you need and you can hone it out to the desired size. You might find that this clamps better than a smooth bore as well.

Of course I don't know where you will find an ID knurling tool that size.

Cheers,

Kelley

Saw a number of dead end radial slots out from the ID somewhat like on adjustable thread gages...

This'll allow the ID conform more closely to the diameter of the pin as the clamp is tightened.

Ned Simmons

Really hard to say unless you want to talk a bit about the application. Worklight mount? Steering link for a school bus? Might treat each instance a bit differently.

Never used JB Weld? Better than some other epoxies, but that's about it. The fact that it has "weld" in its name doesn't mean it's a substitute for welding.

John Martin

Thanks to all who replied to the original post.

The part is a tool holder for my lathe, hence the need to clamp and unclamp it repeatedly. There was a lot of milling, drilling and tapping that went into the pieces before messing them up, so salvaging them was desirable.

I had access to a college shop during the fall and that's where I did the milling work. When I saw the way this the first one cut, the shop teacher said it should still work fine, but I should have trusted my own instincts and stopped there. Instead, I messed up a bunch of them. Later, when I slit the first one with a hacksaw, I found that the .025" slit was not quite enough to tighten it to the tool post.

I made a jig that allowed me to put the part on the lathe and I bored the rest of them that way and it worked beautifully. Problem is that I have a bunch that are in need of work. Sounds like the only realistic approaches are 1) find a way to slit them wider and hope that works,,

2) boring the hole a bit wider and machining a sleeve that can be permanently installed into the hole, or 3) tossing them.

I've only been hobby machining for a short time and there were a lot of new things to learn in this project. I've learned a couple more things just reading the responses to this (e.g. the use of a beer can, although I never drink the kind of beer that comes in cans).

-Bruno

Bruno wrote:

So there you go, just hack saw a little bit more. In the alternative, use a Dremel with an abrasive wheel. With a wide enough slot, you can wrap a piece of wet and dry sand paper around your shaft rough side out and lap off the tooling marks inside the clamp.

How do I hacksaw another 20 thou? I got the dremel out, but the wheel I have is not big enough radius to get through the slot.

-Bruno

Either make a trip to the hardware store and get a bigger wheel or use your hack saw to make a parallel cut to the slot you already made. Dremel sells an 1.5 inch fiber reinforced cut off wheel.

If you leave a little meat between the new slot and the old slot this will prevent the blade from sliding into the old slot. This will give you more than 20 Thou. but it is just a clamp.