# Tearout using Baltic Birch Plywood on Porter Cable Dovetail Jig



## SvenPHX

Just received a new Porter Cable dovetail jig:










I wish to use the jig for the joinery on some pretty heavy duty drawers out of 3/4" (18mm) baltic birch plywood. The router bits are brand new also, they're the Porter Cable router bits that were supplied with the jig. I had a tinker earlier today and had some pretty awful tearout on the front side, I had a sacrificial piece clamped in the jig and got no tearout in the rear, which will be the outside of the drawer.

Here's my awful first try with the router at full speed:










This will definitely show inside the drawer.

In the next attempt I tried the router at its slowest speed. The tearout is better, but still not any good. You can see this on the dovetails below.










I then tried to remove the majority of the waste with a 1/4" straight bit which also resulted in tearout, as you can see below:










I'm sure others use this jig for cutting dovetails in plywood. Any tips to help me out before I have to look for another way to do it?

-Steve


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## bobasaurus

You'll probably need some kind of backer board on one or both sides of the plywood to prevent tearout.


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## SvenPHX

Thank you! With adding a scrap piece to the front too the results are excellent.










I tried the pins at first without the front backer board and it had tearout also. When I added the scrap piece it worked like a charm.










I have some fine tuning to do as the joint is a tad tight and the depths are not quite correct, but I'm satisfied with what I'm seeing so far.

Thanks again!

-Steve


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## KevinDrake

How did you attached a scrap piece to the front? Can you provide a photo?


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## SvenPHX

Sorry mate, this was a long time ago and I don't have pics. I attached the front backer board by just using the front/vertical PC jig clamp. Basically, doubling up the piece I'm cutting.

I know that almost anything 1/2" and thicker would work as a front backer board. In the end it turned into too much of a pain to do so I used 3/4" Poplar which machines so much better.

-Steve


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## runswithscissors

I learned early on not to try to make dovetails with plywood.


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