[longb4]

Hey there! Big fan of your articles and videos. I've been building box joints recently and even though the forces they're subjected to are not nearly as pathological as what you tested, I enjoyed your box joints and dovetails strength testing article: https://woodgears.ca/dovetail/strength.html

Quick question: do you recall what wood you used for the box/dovetail article? It looks similar to the spruce from the earlier joint strength article. I suppose using a stronger wood would just get you closer to where the glue is failing more than the wood, but I'm just curious.

Less-quick question, feel free to punt/ignore: any thoughts on deliberately building in a very, very slight gap between box joint fingers? I would expect this to reduce joint strength (thanks to reduced force between fingers and surface area in contact) but potentially also mitigate wood stress from movement in service due to humidity. Though I imagine if a work piece is big enough for me to be concerned about movement in service, I probably shouldn't be using box joints!

[MatthiasWandel]

I'm pretty sure that wood was birch.

As for gaps in joints, if its a small gap, it doesn't hurt. I actually did some tests in that regard, linked from the article. http://woodgears.ca/joint_strength/glue_methods.html

A small gap actually helped. Probably because the glue soaks into the wood, so a joint without any gap sort of runs out of glue too quick (my theory). But it suggests that putting glue on and leaving the joint open for a minute may be beneficial.