Question about tearout in plywood

[Louis Brandt]

Hello,

I need to build a bookcase, and I’m questioning whether to use plywood (maybe birch or oak). My question concerns tearout. If I need to cut some 1/4 inch or even 3/8 inch deep rabbets and dados (with a router) into the 3/4 inch plywood, would I be risking a lot of tearout, since I’d obviously be cutting deeper than the outer ply layer?

Thanks,
Louis

[Bill Huber]

Not really a problem if you use a down cut router bit.

[Richard M. Wolfe]

As Bill said, a downcut bit will help. With plywood I have had more trouble crosscutting with a table saw cut creating tearout than a router. The worst place I've had is at the end of the cut at the edge where the bit exits. I like to leave a little that can be trimmed off (when I think of it :o) in case that happens.

[glenn bradley]

+1 on downcut. If the ply is severely tearout prone, score the line with a ravor knife.

[Simon Dupay]

Don't use cheap or dull bits either.

[Dino Makropoulos]

Use good plywood from your local panel supplier.
Tape or prefinish the plywood before routing. Or both.

good luck.

Here is a thought that may help many woodworkers.
Plywood suppliers in my area are selling ONLY to trade.
I use my account some times to buy good quality ply at HD and Lowes prices
for other woodworkers. Friends, customers and diy's that they can't establish an account with the distributor.

What about if "someone" establish national accounts with many distributors and allow "members" to "pick" what they need.
It's like a buying club for woodworkers.

That will help with splintering and the pockets.;)

[Cliff Rohrabacher]

Not really a problem if you use a down cut router bit.

What he said.

Oak is pretty chippy stuff. About the only time I ever use scoring on my saw is when I'm doing oak ply.