Need advise on reparing broken leg on old wooden desk

During a move I broke one of the wooden legs of a (circa 1940) wooden desk right where the round turned leg was attached to the square top that forms the corners of the case. Of course it's not a clean break, though it's not that jagged either, and I can fit the two halves together by hand quite closely.

I'm intending to repair the break by drilling for and inserting a metal "dowel" of some sort as a strength member between the two pieces. I have an older 3/8" drill mounted in a portable drillpress which I'm pretty sure can be used to drill the hole into the case part along the axis of the leg quite accurately. But I have no lathe and I don't see a good way to align the hole in the tapered rounded leg axially. I have 1/2" (tabletop) drillpress on which I could tilt the table. I haven't had the table tilted in the last

30 years so I don't know if it will rotate further than the marked 45 degrees but I see no stops that would prevent it from going (close to) vertical. Since this is a tabletop drillpress, there's not enough room to put the leg between the chuck and the base, though (it looks like) I can swing both the head and the table out over the edge of the stand to get space down to the floor.

I'd like comments, suggestions -- and even constructive flames -- concerning the following scheme:

  1. Swing the head and table around so that they're no longer over the base but rather clear of it. Measure the taper angle of the leg and set the table to 90 degrees - taper angle so that the axis of the leg would be vertical when clamped into a v-block against the table. I think that this should give me the ability to drill exactly parallel to the axis of the leg.

  1. I don't know how to get the exact center of the broken end of the leg and there's no part that's even close to the exact diameter of any (Fostner) drill bit I have to use to create a jig, though I guess I could try to (patiently) use an adjustable circle cutter and chisel out the center to get a center finder. Any comments or suggestions?

  2. I think I can locate the "exact" center of the square end of the broken leg on the case by "drawing" the two diagonals.

My biggest fear is getting the holes in the leg parts off-center relative to one another.

Now -- here's another thought on which I'd like comments. Epoxy glue is significantly stronger than wood. If I can get even a sloppy hole in the two parts into which I can insert a "spline", I should be able to use the jagged break to align the leg with respect to the case and a level together with a custom-cut tapered wedge the same angle as the leg taper clamped to the leg with a level to get the leg vertical. When the glue sets, the whole joint will be stronger than the original wood was. _Please comment_.

Thanks in advance.

Norm

Reply to
Norm Dresner
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That sounds the right sort of idea, but personally I'd use a wooden dowel. If you use a strong timber - even a broomstick - rather than typical decorative dowel stock, then this is a strong enough repair for a desk. Chairs are always a bit harder, because of the racking forces, but desks are a nice simple static load.

Good bench vice, a hand-turned drill and eyeball it. If you're _SLOW_ then you can do this accurately enough. Using an electric drill _will_ encourage you to squeeze just that little bit too hard when "it's going well", then you'll screw it up.

Start out by chiselling a flat and square starting plane for the drillbit..

Chisel the middle flat. Then use a pencil and finger to draw a tiny circle in the centre. Eyeballs are surprisingly accurate, if you take your time.

Of course this will happen, for some tiny value of "off center". What you actually mean here is "How much gap filling will the glue be doing, after I've adjusted the hole to allow correct alignment".

If you're averagely careful, then the hole will be close enough to allow white glue or hide glue (your call) in a nice closely fitting joint. Don't make it _too_ tight, or you'll squeegee the glue off the dowel as it goes in (and remember to groove the dowel sides a little too).

If it's sloppy, then change glue. I'd go for epoxy with cellulose fibre filler in it, maybe microballoons on a valuable piece (easier to dismantle in the future). Some people might use PU glue, which will gap fill anything easily, but I've never liked the stuff myself.

That should be sufficient to give you a good result.

For clamp up here, I'd splint a leg that was easy, but not one that required tapered shims. For doing those I turn the piece upside down and use a brace on the top part, jury-rigged from a chemistry lab stand and brackets (these are useful workshop equipment, and worth scrounging if you ever get the chance)

Reply to
Andy Dingley

At least one aspect will be in perpetual shadow, won't it? How about gluing up, groove in the hidden side, reinforcement inserted.

Reply to
George

Dowel joints have to be exceptionally accurate even under normal circumstances, but in this case it would have to be perfect. Even a few thousandths of off would be too much considering the jagged edges have to meet perfectly. I strongly suggest you forget about that scheme. It won't work with the tools and techniques you described. The obvious course of action would be to just glue and clamp the break without any reinforcement. That's what I would do. It might even be more or less as strong as the unbroken wood that way, but in any case it would only break again if you had another major accident. I wouldn't use epoxy either. The bad thing about epoxy is that once it hardens, it is there forever. You will have a real mess on your hands of you have a false start with epoxy. I would use hide glue because it is reversible. If it doesn't go together right, you could (with some difficulty) take the joint apart again and reset it. If you feel you must reinforce the joint, do it after the break is glued together and square. You could put a spline in the back side as someone else said. If the top is not in the way or can be removed, you could drill from the top with an appropriately long bit and add a dowel that way.

Reply to
Hax Planx

Hax has the right idea. Dowling is clearly an invitation to disaster. Practice hand fitting the pieces dry. If you can get them to fit together accurately, a simple glue job should be adequate. A conventional wood glue joint is often stronger than the wood. Conventional wood glue would give you time to adjust the alignment of the parts. Hyde glue would give you the opportunity to disassemble.

Dick

Reply to
Richard Cline

The easiest approach if I were doing the job would be microballoon thickened epoxy.

Mask of the areas where you don't want the epoxy and go for it.

I can see absolutely no reason why you would want to take this repair apart, so don't understand the hide glue approach.

As far as any kind of a mechanical aid approach such as a dowel, I wouldn't go there.

No matter how you approach doweling for this job, you will never get it perfectly aligned.

Close, yes, but perfect, no.

BTW, the epoxy will be the strongest repair you can make.

Lew

Reply to
Lew Hodgett

Well, the idea was that he could start over if the first attempt didn't work out.

Reply to
Hax Planx

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