Wooden Internal Corner Braces 12 14 2025

Part A of article.

So two different types part of consideration.  B & C or A & D.

B & C have a rounding to the edge.

Whereas:

B & C round to stop at would be about a 1/8" outcrop.

Part B of article.

So let's say you had no way to find a 45 degree angle.  No 3x5 cards you can fold, no protractors etc.  Assumption #2 all wood is same thickness.

Reference Hi and Ho in diagram.  How can you mathematically mark off Hi shorter than Ho to cut the 45 degree angle?

It has to be really simple even though I never thought it out before.

You subtract the fixed width of the wood from Ho on each end and draw a straight line from the squared off end of Ho to mark where you will cut at Hi to be shorter than Ho.   Then you cut and then woodsmith some more from the corner end of Ho to the cutline you formed at Hi.  Hence you have a 45 degree abutting mitre joint.

I know what you are thinking, "You simpleton." Is what you are thinking.  Okay "yew" look around wherever you go at 45 degree joints.  At picture frames, and door frames, window frames, box frames, etc etc.  You will see a lot of them are not perfect.

And so, and hence forth, if you only knew the external dimensions of such a box and the width of the wood the internal dimensions are thusly determined.

And so, and hence forth, capacity and volume can be readily determined.  

© 2025 Thomas Paul Murphy