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by Jedd 2570 days ago
As someone who dabbles in woodwork, I can highly recommend it as a hobby.

Exercising the brain in any new problem domain can often be rewarding in itself, but it's a nice opportunity to blend engineering, practicality, creativity, usefulness.

From TFA, I'm (also) surprised that end-grain screws worked at all well. I appreciate the author was trying to minimise variation between the components, but for end-grain I'd use a much deeper thread, as screwing into end grain is often compared to joining into the end of a bunch of drinking straws. Not that I'd ever screw into end-grain. ;)

Similarly, the makeshift pocket hole jointer isn't clear from the pictures how they got a recessed hole (commercial pocket hole devices use a t-shaped drill bit, and do not drill all the way through the piece). The recommended bits for pocket holes also have a threadless shaft near the head, so the two pieces pull tightly together.

Which leads to the lack of glue in many of those photos. I grew up hearing (but not really believing) phrases like 'the nails are only there to hold it until the glue dries'. Wood glue technology is amazing -- when they say on the bottle 'stronger than wood' they aren't joking. I'd expect to use a lot more glue than shown, and have it significantly affect the results.

2 comments

> the nails are only there to hold it until the glue dries

This is a phrase my brother, a cabinet maker/ jointer, uses... And tests occasionally: Glue 2 pieces of timber together at 90 degrees and clamp it normally. When dry, break the join (by bashing it with a hammer is his general way) to see if it's the glue or the timber. Nearly all of the glue he tests are stronger than the timber (Oz, US and Asian hardwoods), as it's the timber that is ripped apart, and not the glue join.

A bottle of standard PVA-B (/ exterior grade) from the local hardware store is pretty excellent.

When you think about glue, it's everywhere these days. All timber laminates (eg kitchen bench tops, plywood, particle board, MDF, and finger jointed/laminated timber) are just 'glued'. A lot of this is structural timber (ie designed to last decades).

From the article:

> This joint failed by the wood in the post shearing along the growth rings

This is the most common place of failure when witnessing my brother's "tests", and makes a lot of sense it happens that way too. The glue should have been the strongest part of ALL of his tests. It looks like he 'over clamped' the timber (ie squeezed out all the glue) in few of his photos [0]: which is something my brother has warned me about, as it makes the join weak.

[0] https://woodgears.ca/joint_strength/failures.html

Edit: clarification

Indeed. Glue-laminate beams are a wonderful building material: cheap, strong as hell, and friendly to forests since they are made from wood scraps.
The timber extraction industry cares not which tree the fiber comes from and sells it to the highest bidder.

(Actually, they discard pieces that are too small to handle profitably, so they do care a little bit)

I mentioned modern glue to my scientist friend and he said "you know about UV cure adhesives, right?" and that's when I realized glue was everywhere.
> the nails are only there to hold it until the glue dries

I'm only dabbling with woodworking on a very basic level, but realising how strong wood glue is one of the big aha-moments I've had. As the article author mentions, screws are simply not good enough for holding stuff steady, but when combined with glue it's simply redicilously strong.

Right, I've always used pocket hole screws with a glued butt or rabbet, so I would have added the former to the testing.