Drill and re-tap a plane sole?

[sploo]

I've picked up an old Stanley #4 plane (likely a Type 8, so worth restoring). Unfortunately, some complete [insert expletive here] has tried to replace the threaded rod & nut that holds the rear handle onto the sole... with an oversized bolt; destroying the tapped hole in the sole.

I have various diameters of steel rod (smooth and threaded), so I'm wondering if I could either drill and epoxy in a small chunk (or even tap the sole and screw in a chunk), then drill and re-tap that new piece of metal. Is that likely to work - given the mismatch in metals between the
sole and the replacement?

I assume that epoxy probably won't be strong enough - as the rear handle needs to be tightened down pretty hard, so I would need to try to drill and tap the sole to screw in a new section of metal? (i.e. screw in a piece of threaded rod, rather than epoxy in a piece of smooth rod)

 

[Phil Pascoe]

Could you not just clean the hole out, possibly drilling it slightly deeper, and epoxy the threaded rod in? I've always used JB Weld for things like that - I don't know that it's significantly better, though. I've never had a joint made with it fail.

 

[AndyT]

I've never done it, but it ought to be possible. It means you can avoid the distraction of the special Stanley threads as well, by drilling out to tapping size for the next metric size up, which is probably M6. You probably know that for tapping a blind hole you need a "plug" tap, which is not tapered. This is a bit trickier to steer than a tapered or second tap, especially when you have so little depth to work with. (If you have a broken carbon tap it's worth grinding the end down square for this purpose.)

You'll need to enlarge the hole in the brass nut at the top of the rod as well, unless you have a special Stanley die or do something clever by welding old and new rods end to end, so make sure there's enough metal for that.

 

[sploo]

The plane doesn't have the original rear threaded rod, but I have some modern spares that I think are metric (so I would have a tap). I'd rather not epoxy it in though.

Ok, I'll have a go at making a sleeve - thanks.

 

[AndyT]

Just reread your post and realised that it sounds like there's no longer enough metal left to tap.
For a plane this far gone, if Phil's straight epoxy fix doesn't work, you could try just drilling straight through, and countersinking for a long machine screw going up through the sole. Fill in the hole afterwards with epoxy/Isopon or similar and smooth off when hard. It won't look pretty but the wood won't know.

 

[sploo]

Just reread your post and realised that it sounds like there's no longer enough metal left to tap.
For a plane this far gone, if Phil's straight epoxy fix doesn't work, you could try just drilling straight through, and countersinking for a long machine screw going up through the sole. Fill in the hole afterwards with epoxy/Isopon or similar and smooth off when hard. It won't look pretty but the wood won't know.

There might be enough metal; the oversized bolt does screw in, so whilst there's not much depth I might get away with it. I will need a bottom tap though as I don't own any.

 

[galleywood]

Some pics might help to give you the best fix.

If you go for fitting a plug that you can screw the rod for the handle to, you might want to drill and tap it before fitting it to the plane body.

 

[sploo]

Some pics might help to give you the best fix.

If you go for fitting a plug that you can screw the rod for the handle to, you might want to drill and tap it before fitting it to the plane body.

I was thinking of that. It'll need a hole at an angle, so tricky.

 

[MusicMan]

Try a helicoil insert. Made for this job (literally). You can get them in metric in most sizes.

 

[sploo]

I've checked the new rods for plane handles that I have, and they are indeed metric (M5). The bolt that's been bodged into the plane sole looks to be 1/4", so I'm assuming it's a UNC 1/4-20. The depth of the existing hole appears to be between 7 and 9mm (deeper at the back, as the hole is angled into the plane sole).

I guess then that an M5 x 0.8 helicoil would be the right thing, in a 1.5D length (7.5mm). I assume the external diameter of that helicoil would be somewhere between 6 and 8mm?

 

[DTR]

The tapping drill for an M5 helicoil is 5.2mm, so it won't remove all of the 1/4" thread. An M6 helicoil would be more appropriate, but obviously will not fit your rods. Unless I've got the wrong end of the stick?

I've got an M6* helicoil set in the shed, I bought it for a one-off and haven't touched it since. If it's any use, PM me your address and I'll bung it in the post.

* at least I think it's M6, I'll have to double check when I get home.