Replies

1. 
   rob_ss | Dec 23, 2020 09:31pm | #1

   It will probably be as strong as the original if you simply use wood glue, as long as you can get some decent clamping pressure on it.

   Your best preventative in future would be veneer applied on the top and under-surface of the lamp.
   The reason this piece has failed is the short grain sections - curves of this type cut from a single piece will always have this problem. If a force is applied to the lampshade end, it will compress one side of the wood and stretch the other, with failure as a result. A thin sheet of veneer applied with the long-grain along the length of the piece will prevent most failures as the strong fibres will prevent the short grain segments from separating.

   You could strengthen the failure point by inserting a dowel. This would result in a much stronger joint on such a small area, especially where you are gluing end-grain in the pole to side-grain in the arm.

   My preference for this design would be to make the arm and pole as a single piece of glued lamination, which avoids all the structural issues. It would not be fun leaving a hole for the cord, but doable.

1. 
   actuary | Dec 23, 2020 09:52pm | #2

   What if I replaced the curve with an inverted U shape? (That is, half a rectangle.) It may not look as pretty as the curve and would have some end grain showing, but wouldn't it be stronger?

2. 
   user-3395150 | Dec 23, 2020 11:53pm | #3

   I would cut a groove on the outside edge with a router and put a spline in it to support the joint.

1. 
   DRBWWing | Dec 24, 2020 08:28am | #5

   My thought, too. Route the groove 3-4” either side of break.

   Good example of designers with inadequate knowledge of the building material. It’s not an Anna White, is it? LOL.....

2. 
   elmaduro | Dec 24, 2020 08:38am | #6

   That would be my fix as well, rout and spline.

3. 
   john_c2 | Dec 24, 2020 02:58am | #4

   That was never going to survive. Too much weight on short grain, and it was always going to split. Plywood veneered with your show wood might have worked. Being hollow, for the wiring, maybe even some sheet metal laminated under the veneer.

4. 
   _mj_ | Dec 24, 2020 08:50am | #7

   Cut the whole arm into 3 slices and insert cross-grain veneers or the next time it tips over the other end will break. Take the lower 4" of the center slice out and replace it with an 8" vertical grain insert that you can splice into the stand.

   If you do the slicing on the tablesaw you'll have room for nice heavy shopsawn veneers and wind up at the same thickness.

5. 
   actuary | Dec 24, 2020 09:29am | #8

   The lamp survived for 5 years until it was accidentally knocked over.

   What do you think of inserting and gluing metal pins (nails with the heads cut off) to re-attach the curve to the pole?

   Alternatively, what if I replace the curve with straight pieces so it's more like a bridge? Shouldn't that generate less stress at the connection point?

6. 
   bilyo | Dec 24, 2020 01:32pm | #9

   I think that the curved piece should re-made as a bent lamination. Just rip strips 1/8"-3/16" thick and glue them together over a curved form. Embed some tubing down the center for feeding the wire through if you like. Shape it as you prefer and finish. It should be very strong and last a lifetime.

1. 
   john_c2 | Dec 24, 2020 06:29pm | #10

   Great way to do this.