Box Joints And Chipout

[Paul Douglass]

I am making tool box out of some 5/8" plywood. I would like to use box joints in the corners but I haven't been able to cut the slots without having real bad chip out. I have a freud stacked dado set, and a box joint jig with a backing board. Unfortunately I have to cut across the grain of the outside laminate on the plywood to get the size box I want. I've tried tape, no help. Any suggestions, Besides don't do box joints? I really wanted to use my neat box joint jig. :mad:

[Dave Richards]

How about running a sharp knife along the veneer at the limit of the joint? Give the veneer a controlled place to break.

[J D Thomas]

Try placing some scrap stock on the outfeed size of the blade. The scrap will take all the outfeed abuse and your good stock will come out unscathed.

[Paul Douglass]

I have a support board, and I tried the cutting with a chisel and a utility knife. The cuttung helped but still too much chipout. The only other thing I can think of is cut with bandsaw and than to the boxjoint jig to clean out. I don't know if I am that ambious! The problem is cutting accross the grain of the outter layer of wood. Plus, this wood is very old, like from cabinet doors from cabinet made in the early '40's. Very dry and brittle.

Thanks for the replys

[Dennis Peacock]

With old and brittle wood like that, you will need to use a "combination" of anti-chipout techniques to achieve your goal.
On a "whim" one time, I did this:

Applied 1.5# cut of shellac to the surface to be cut, applied strong masking tape to the surface to be cut, used a fresh backer (1/8" hardboard) for each new cut (translated here, new board), and finally I had to clamp the board being cut, tightly to the box-joint jig so the space between the board I was cutting and the backer board was zero spacing. Now maybe that's a bit extreme, but I finally got the cuts clean enough to call it "good".

[Paul Douglass]

sounds like a lot of work, I think I will use a different joint this time and save the box joint for better wood. Thanks..