Plywood tenon?

[cgallery]

Can I use a piece of 1/4" plywood as a tenon for joints in solid wood? Or will the fact that the plywood doesn't expand/contract like solid wood cause the joint to crack?

TIA, Phil

[charlie b]

no

charlie b

[B A R R Y]

Yes, and it makes good "splines" too. A spline is kind of a long, shallow tenon inserted into grooves on both sides.

Most woods don't move enough to make that an issue in the case of a typical 1-2" long tenon.

Don't forget when making your mortises that 1/4" plywood isn't really

1/4" thick!

[Charley]

Plywood will work OK as a loose tenon, but you will have an even stronger joint if you use a solid piece of wood with it's grain oriented across the joint. You can't achieve this with plywood

[J T]

Mon, Oct 23, 2006, 2:12am (EDT+4) [e-mail] (Charley) doth stateth: Plywood will work OK as a loose tenon, but you will have an even stronger joint if you use a solid piece of wood with it's grain oriented across the joint. You can't achieve this with plywood

You've lost me on that one. How about explaining just whatcha mean?

JOAT It's not hard, if you get your mind right.

- Granny Weatherwax

[Andy Dingley]

Yes. If you're working at 1/4" or thinner, then the best way to make an accurate tenon this thin might well be to use ready-thicknessed plywood.

I wouldn't recommend it for big carpentry, but it's a fair compromise technique for thin splines.

[J. Clarke]

Solid wood has all the grain oriented the same direction, plywood has half of it (more or less) oriented perpendicular to the rest. In a tenon the major loading is going to be shear across the grain of solid wood--half of the wood in plywood is oriented in a direction that provides little strength in that direction.

Further, leaving aside the difficulties of glueing such woods, you can make a loose tenon out of Ipe or Lignum Vitae and it will be vastly stronger when loaded in shear across the grain than will birch or douglas fir.

[J T]

Mon, Oct 23, 2006, 10:03am [e-mail] (J.=A0Clarke) doth sayeth: Solid wood has all the grain oriented the same direction, plywood has half of it (more or less) oriented perpendicular to the rest.

Yep, already know that. But, I would be thinking that the joint would destruct before the strength of the tenon counted, especially if the tenon is only 1/4"

JOAT It's not hard, if you get your mind right.

- Granny Weatherwax

[fredfighter]

Huh?

Isn't it the tenon that holds the joint together?

Otherwise, why use a tenon?

[J T]

Tue, Oct 24, 2006, 8:56am (EDT-3) [e-mail] doth query: Huh? Isn't it the tenon that holds the joint together? Otherwise, why use a tenon?

Durned if I know, anymore I'm just confused by ll it all. I think I'll just stick with dowels.

JOAT It's not hard, if you get your mind right.

- Granny Weatherwax

[Paul D]

[J T]

Thu, Oct 26, 2006, 11:59pm (EDT+14) [e-mail] (Paul=A0D) doth sayeth: Stick with dowels ..... small round loose tennons

Not loose the way I use 'em.

JOAT It's not hard, if you get your mind right.

- Granny Weatherwax

[Paul D]

THe term 'loose' was used loosley

Not loose the way I use 'em.

JOAT It's not hard, if you get your mind right.

- Granny Weatherwax