Dowel joint vs biscuit joint

[Adam9453]

I think it was a YouTube video, I'll see if I can find it again

 

[sploo]

A dowel has very little face-grain to face-grain surface area. Sure it goes in further than a biscuit, but a biscuit is entirely F2F, and it also occupies more of the width of the wood.

Yea, that's a fair point - though biscuits themselves are pretty weak (and mostly intended for alignment, as far as I understand).

Wouldn't the dowel face-grain argument also apply to dominos though (even though they've got more surface than a similarly sized dowel)? AFAIU dominos are hugely strong.

 

[Mr T]

If dominos are aligned correctly they have quite a large F2F surface area, it's just the rounded ends that are not.

Bisuits are less likely to pull out than dowels but because they do not penetrate as far into the wood there is more danger of the surrounding wood splitting with biscuits.

Chris

 

[Adam9453]

I don't think so.

A dowel has very little face-grain to face-grain surface area. Sure it goes in further than a biscuit, but a biscuit is entirely F2F, and it also occupies more of the width of the wood.

Adam, do you have a reference for that? I need to be convinced.

Here you go Steve, it's a very comprehensive test;
http://paul-flores.com/downloads/Joinery_Failure.pdf

 

[Paddy Roxburgh]

I'm sure I've read joint strength tests where dowels out perform biscuits, might well have been from the manufacturers of dowel jigs though so caution required. just found this https://www.canadianwoodworking.com/get ... owel-joint. FWW did some tests but you have to sign up to see the results. In my opinion all these test are flawed as most joints do not break from racking pressure but from glue failure after time.
A FWW video says that pinned mortise and tenons are not as strong standard M and Ts and lap joints are the strongest. This may be true in a racking test, but if the glue fails in a lap joint then the two pieces of wood separate. A draw bore M and T will hold together even if no glue is applied.
Paddy

 

[Adam9453]

I'm sure I've read joint strength tests where dowels out perform biscuits, might well have been from the manufacturers of dowel jigs though so caution required. just found this https://www.canadianwoodworking.com/get ... owel-joint. FWW did some tests but you have to sign up to see the results. In my opinion all these test are flawed as most joints do not break from racking pressure but from glue failure after time.
A FWW video says that pinned mortise and tenons are not as strong standard M and Ts and lap joints are the strongest. This may be true in a racking test, but if the glue fails in a lap joint then the two pieces of wood separate. A draw bore M and T will hold together even if no glue is applied.
Paddy

That's an interesting point, however with modern glues I think the risk of glue failure is minimal. However perhaps doing both wouldn't hurt if failure of the joint is a problem that you can't risk in a particular situation. FYI the link I posted above is the results of the test you mentioned which you can view without needing to be a member, it does make interesting reading

 

[sploo]

Here you go Steve, it's a very comprehensive test;
http://paul-flores.com/downloads/Joinery_Failure.pdf

Interesting results, but I don't think I'd have gone for a single 10x50 domino in stock that wide; probably two (slightly) smaller dominos side by side. I suspect (though wouldn't put money) on that giving a better result.

 

[Sean Hellman]

I have a Mafell for dowels, had it for years. Just that bit more versatile than a biscuit jointer. Can a biscuit jointer join a 1inch end grain square rail to a 1 inch post? My Mafell can. As far as I am concerned dowels and biscuits are to locate the wood not necessarily to provide more structural integrety. Bad example as this type of joint will quickly fail with glue alone. Glues these days are far stronger than the wood.

 

[custard]

I have a Mafell for dowels, had it for years. Just that bit more versatile than a biscuit jointer. Can a biscuit jointer join a 1inch end grain square rail to a 1 inch post? My Mafell can

Are you talking about the Mafell Duo Doweller? Given that the two dowels are at 32mm centres I don't see how it can "join a 1inch end grain square rail to a 1 inch post".