Reattaching a broken leg

[Norm Dresner]

I've got an (semi) antique desk with a broken leg. The turned, ~1-1/2" diameter tapered leg was originally attached to the case with using a ~1" diameter round M&T where the top end of the leg was turned down to that diameter and the case had a corresponding hole. Of course, the tenon has shattered and, while I could fit the leg and case together with little interior wood showing, there would be no strength in a joint formed by just gluing the two pieces together,

I guess the right way to do this is to do some sort of doweling, perhaps a

1/2"-3/4" diameter down drilled into the top of the leg and the bottom of the case to give it some sort of structural rigidity. I have no lathe so I can't possibly "drill" a concentric hole in the leg that way.

I'm open to suggestions as to how to proceed to produce the strongest repair.

Thanks in advance

Norm

[Walt Cheever]

If you can get access, I would glue the leg back into place as a temporary positioning method.

When it's set, go in from the top and drill another mortise about 3/4" dia, and glue in a dowel. That way, if the hole is a bit off center, it doesn't make a difference. You'll still have to be gentle, when you've cut the hole, there won't be much wood in contact with the case.

Walt C

[George]

Me too. Further, though this is a woodworking group, I don't believe anyone would fault you for using a 1/4" bolt as a dowel.

[Guess who]

The best I can offer for now:

You should be able to support the leg in a jig and cut off the "shattered" tenon square to the leg. You should be able to find and cut a piece of 1" hardwood dowel. Drill that dead center [see below]. Mark the cut off leg dead center, and *start* to drill the same diameter hole [ about 1/4" deep should do].

The hole(s) should be small enough to accept a long enough screw. They should be small diameter to start with, then widen as needed to match the screw. Holding the dowel onto the leg, continue to drill through the dowel, and the leg to an appropriate depth. The screw doesn't have to bite all that hard, just enough to keep them drawn together while gluing.

You will be gluing and screwing them together. When set, this should fit the old hole.

[Andy Dingley]

Drill the leg, glue a dowel in, use this to reproduce the original tenon.

Slow hand-drilling (ideally with an assistant eyeballing on both axes) is accurate enough for this. If you need to, enlarge the old mortice to accept the nearest diameter-matching dowel.

[Peter Ashby]

Except that the same stresses that caused the original failure will, with a metal bolt result in the leg giving way in the face of the superior material strength of the bolt, iow it will come out of the side of the leg. So if you use the bolt, it will work but next time the repair will require a new leg.

Peter

[George]

Or the superior strength of the dowel.

You use rolled-up paper in your repairs?

For what it's worth, the repair will not allow the original conditions to pertain.

Sheesh!

[Walt Cheever]

Andy,

I like your answer better than mine. The suggestion to build a jig for drilling is an excellent one too.

Just be aware that a 1" dowel sold in the usual lumber store is anything but

1", probably smaller by enuf that the glue joint will fail, DAMHIKT.

So, if it's worth the work, pull the leg, mark the center of the stub, cut it flat to the leg, and drill a new dowel/mortise hole full size. Use a jig, spotter, what have you to get accuracy. What say all of you--what should the depth be? I'd try for 2" just cause I'm conservative.

If the actual size dowel is too small, buy the next size larger and shave it down to fit (chisel, block plane) like you would an overgrown tenon. Clean out the old hole in the chair, and glue it back together. I'd consider using epoxy glue, as it will bridge minor gaps, as opposed to yellow glue which won't.

I really disagree with the suggestion of using a 1/4" screw or even a 1/2" screw to replace it. For some very good structural reasons, the joint will break again, and even though the wood is in contact with the wood, the steel will be acting like a hinge for a very floppy leg. Chair legs take a LOT of stress, and that one broke for a reason.

Or, you could spoil the fun, and look up a furniture repairer to do the job. If something is semi-antique, maybe it needs to be repaired by someone who has done it a time or two before. I realize that's inflammatory on this list of those of us who feel we are experts, though.

Good Luck, let us know what worked!

Walt C

[Lowell Holmes]

Doesn't Flexner have a video about such repairs? It seems he scarfed new wood on to the damaged leg and then shaped it to match with spoke shaves. Maybe it wasn't Flexner, but I recall it was someone normally associated with finishes rather than woodworking. It seems that those skilled in one of those disciplines is usually skilled in the other.

Logic tells me that you have to get past the week wood in order to effect a repair.

I think it is a worthwhile endeavor.

[Lowell Holmes]

I can't believe the grammar errors I let get out in the last post. I definitely need to read my posts prior to sending them. :-)

[Peter Ashby]

Softwood in hardwood?

Why don't you trivial the point instead of arguing it?

Won't they? why did that leg fail? maybe the piece is not dead square all around and so there are torsional forces acting on that leg? Putting it back will not fix that, so it is likely to fail again. Your repair thinks only about now. This is an antique, think about the restorer in another 100 or so years.

Try argument instead of emoting and you may carry more force.

Peter

[Andy Dingley]

Not such a bad idea, if it's strong enough for regular use. If you ever break it again, you want the down to break, not the leg to split.

[Peter Ashby]

The hard part is, with that restorer in 100+ years in mind, do you drill out in metric or imperial or guess what they might use then? :-)

Peter

[Norm Dresner]

Since Fostner bits are available in 1/8" (and sometimes 1/16" increments -- I have no idea what's available in metric) it probably doesn't matter much which is used as long as it matches the dowel now.

For the record, I was the OP and the desk leg broke because I was stupid in trying to handle it alone in the truck instead of getting someone up there with me to turn it from back-down to top-down on the moving pads for sliding it the length of the truck box, I twisted it a little too much and wound up pressing down on a single leg.

Also, the desk appears to be solid mahogany so I'd guess that a hardwood dowel would be more appropriate -- though I'll probably not get to match the wood species exactly and I'd never get to match 60+ years of drying.

Norm

[Andy Dingley]

Why not ? I broke up a flat full of 1930 furniture a week or so back. Owing to woodworm I couldn't save more than a couple of pieces, but there's a fair bit of oak that they didn't eat (the beech frame and ply panels had vanished into dust). It's now in the timber racks, all ready for re-use.