It is not uncommon for a chair or table leg to break.

 

Here are a few techniques

 

1. If the split is along the grain, my general rule is 30 degrees or less, glue the joint and clamp together.   There are a couple of good ways to get the glue in.  One is to use a medical syringe.  You can get fine diameter ones as insulin syringes at a drug store.  No Rx is required.   If you want a larger one, farm supply stores like Rural King or Tractor Supply set vet versions, sometimes the needles are at the checkout.    Another way is to lay a bead of glue on one side and put your shop vac hose on the opposite side, the suction will suck the glue in.   If the leg is an odd shape, you can wrap with a strip that you have cut off an innertube.    Most cars don't use them any more, but most bicycles do.

 

2. If the fracture is within a few inches of the end, glue the piece back on as above, then drill in from the end and glue and insert a dowel extending an inch or two beyond the fracture.  When shopping for dowels, look for ones with more or less straight grain.  I have some hickory ones that are particularly tough.  Don't go for the cheapies.  Horizontal boring

 

3. Sometimes there is a split in the top of a leg where the connection is a threaded insert  I don't know why there is two or more inches of wood there, the pilot hole is about an inch and half, but the threaded insert is in the first 3/8".     Take the threaded insert(s) out, glue the crack, and if there is room, drill a pilot hole and secure the split with screw(s).  Then put the threaded insert in about as deep as it will go and the bolt will still reach it (usually not a problem).  It will then be in "fresh meat" and be in compression, not tension.  You want to have threaded inserts with the 8 mm hex drive, not one with a shoulder. 

 

4. Although I've never seen it, similar breaks as #3 could happen if the leg has hanger bolts (wood threads on one end, machine threads on the other).  Get a longer hanger bolt and drive it deeper, drilling a deeper pilot hole if needed.   A good way to insert hanger bolts is to put on two nuts on the machine thread end.  Jam them tight together with a pair of wrenches.  Then put a wrench on the top one and use it to drive the hanger bolt in.  When it's set simply loosen the top one and take them off.

 

5. If the break is near a detail like a turning, bead, kerf, etc., particularly if it's a cross grain fracture, not a long split, do this. 

• Drill a pilot hole for a dowel, centered into the break at one side where there is a detail nearby.   Drill past the detail at least and inch or more. Horizontal boring
• With a fine kerf saw, saw at a convex point right at a detail, preferably on the bottom side, if possible. 
• Glue this cut off piece back onto the other part, clamp end to end and let dry.  
• When dry, using the same size drill bit, drill thru the sawn off piece into the other piece, making perfect alignment.  
• Cut a dowel to length, leaving about 1/8" short, glue, insert, and clamp on the ends of the legs to draw together. 
• Touch up the sawn point if needed.

Edited May 8, 20223 yr by kmealy

Thanks!