Is it tongue and grove or grove and tongue?

[rudy de haas]

In this case I am making shelves out of 12mm (about 1/2 inch) baltic birch plywood with jatoba decorative strips on the front. If I make the jatoba strips 12mm x 12mm x length of shelf is it better to put the tongue on the plywood or on the front strip? There is one obvious difference: putting the grove into the jatoba leaves a thinner jatoba strip - but so what? Does it make a difference? and, if so, which way is better?

[Mel Fulks]

I've never seen or used a tongue on plywood, but sometimes plywood is used as a spline to align glue joints. But you have to be careful if you don't have shaper and feeder. With piece that small sometimes it's easiest to not use a tongue ; you can use tape for alignment and ,or, clamping.

[Osvaldo Cristo]

I would use simple and direct gluing... it does not look me T&G could add anything in practical terms.

[Doug Hepler]

Rudy,

I agree with Osvaldo. A butt joint would be sufficient for 1/2" edge banding. If you decide to use T&G I recommend that you cut the tongue on the jatoba. Cut the tongue into the stock piece and then cut the strip off. Do not attempt to cut the tongue after you cut the strip.

Doug

[Jim Becker]

A butt joint is sufficient for strength, so any T&G or biscuit or spline or whatever is going to mostly only provide an alignment advantage. If you do choose to use T&G, I'd put the tongue on the hardwood and the groove in the plywood.

[Robert Engel]

Its tongue and groove either way kinda sounds like an R rated dance, doesn't it? LOL.

[Mike Cutler]

A butt joint is sufficient for strength, so any T&G or biscuit or spline or whatever is going to mostly only provide an alignment advantage. If you do choose to use T&G, I'd put the tongue on the hardwood and the groove in the plywood.

I agree.
12mmx12mm is a very small piece cross section. Other than for alignment purposes, I don't see the advantage of a T&G joint here.
There are edge banding router bits, and shaper cutters, to perform this work. An option if you don't want to use a simple butt joint. Here is an example. There are others.

https://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bit_edgeband_ogee.html

[rudy de haas]

Thanks all!

I do have a shaper/feeder so cutting these isn't an issue - and, of course, I'd cut the joint on the jatoba on a wide piece and then cut the stip.

This is baltic birch so quite dense - cutting a tongue on cheap plywood is, as Mr. Fulks says (above), a non starter - but it seems strong on this stuff.

Looks like people think a butt joint adequate but putting the tongue on the jatoba gets two votes if I want to that anyway. Question is: does it (where the tongue goes) make a difference? I've done tests both ways and it doesn't seemlike it matters except that putting the groove in the plywood protects the outer layer from splintering.

[Alan Schwabacher]

You could groove both, and use a spline.