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Andrew Kertesz
12-15-2016, 6:28 AM
Has anybody used BB plywood for loose tenons? I'd be interested in hearing the pros and cons on this. Quality plywood is; stable, very little shrinkage or swelling, just seems to me to be a good choice. Thoughts?

Thanks,
Andy K.

Wayne Lomman
12-15-2016, 6:59 AM
It's ok if it is a structural plywood. I don't know what the equivalent body in the USA is called but if you search the Engineered Plywood Association of Australia you will learn the difference between plywood and structural plywood. BB is an unnecessary expense. It won't be seen so CD would be fine. Cheers

John TenEyck
12-15-2016, 12:53 PM
I could see using it for right angled tenons, like was recently shown in FWW, but for normal straight tenons I don't see a benefit over using solid wood of the same species I'm building something from. That way, there is no difference in seasonal expansion/contraction.

John

John Lankers
12-15-2016, 2:40 PM
I've done it several times, also as splines to reinforce mitered corners.
It's an excellent way to use up scraps IMO.

Jim Dwight
12-15-2016, 5:04 PM
The tenons of plywood will not be as strong for normal stresses on a mortise and tenon because aproximately half the wood in the tenon will be oriented wrong. Most joints are stronger than necessary, however, so it may not make a difference.

lowell holmes
12-15-2016, 7:45 PM
I prefer white oak for loose tenons. It is strong and stable.

John TenEyck
12-16-2016, 10:49 AM
I prefer white oak for loose tenons. It is strong and stable.

Actually, WO is not all that stable, that's why it's often used as quarter sawn. WO tenons would be a fine choice if building a piece with WO, and it may not really make much difference since tenons are generally not too wide, but I try to use the same species for the tenon as I use for the piece to avoid any potential problems.

John

Eric Rimel
12-16-2016, 7:04 PM
I used 1/2" BB once and it worked great. The biggest issue I have with using plywood of any kind as loose tenon stock is the ply thickness. I cut my mortises and size the tenon stock to fit as opposed to trying to size my mortises for an exact tenon material thickness. I made a mortise jig that when used with a 3/8" bit and certain template guide, 1/2" BB magically fit perfect. It was a happy accident.

Chris Fournier
12-16-2016, 8:24 PM
I wouldn't bother with BB. I use hardwood that I can easily hand plane to a perfect fit. I pretty much use poplar because it strikes the right balance for me. Have yet to have a failure.