Tear out on a router box joint

[toller]

I have a homemade box joint jig, and have used it without problem on poplar and teak. But when I used it on walnut I had bad tear out on the end cuts. Does it make sense that walnut is more prone to tear out than poplar or teak?

I solved the tear out problem with a carpet taped backer board, but then I had trouble holding the wood steady for the first cut and generated a lot of scrap before getting it right.

Would a spiral bit be less likely to tear out? If not I suppose my options are to make a better jig to secure the wood on the first cut, or (gasp) doing it on the table saw. Or does the table saw have tear out problems of it's own?

Thanks for any advice on this.

[George]

Spiral much nicer, but aren't you using a backer/pusher like the Router Workshop guys? No problem there, and it's also your spacer for the mating cut and template for the next setup. If you don't know what I'm talking about, I can send some jpgs to an address you want.

For the middle schoolers I made a pusher with a vertical board to encourage them to keep their hands safely away.

More than likely that teak has done some dulling, too.

[dave]

George, if you would - post those jpgs for all of us. Inquiring middle schoolers like me would like to see them too.

Dave

[D. J. Dorn]

I simply do all at one time with a Lynn Jig and put the insides of the box on the outsides of the stack. That way, when done, any tearout goes to the inside and you get nice looking, crisp cuts on the outside of the box.

Don

[George]

Would, but my ISP doesn't seem to get things to abpw.

Got a photosite that won't spam me forever?

[toller]

I would appreciate the jpgs. [e-mail]

Yes, I considered that also. It is a craftsman that came free with an old table and has seen a bit of use. I suppose that is enough excuse to replace it with a spirl bit.

Thanks

[toller]

Thanks for the pictures. I have a little sled rather then the rail, but it is about the same idea. My problem is in your second picture; cutting the offset piece. I have not tried leaving a block next to the piece being cut; is that the space you referred to? Probably a good idea; might reduce tear out, but will certainly make holding the work easier. Thanks.

[George]

Yep, that's the beauty of the jig - simple and precise as you care. The use of the spacer to fence the first cut means that the gap which begins the piece can be precisely as wide as the finger that will fill it. You don't see the anti-tearout block behind the piece in the picture.

For the pieces beginning with a finger, and for subsequent cuts on the others the spacer is used as a pusher/tearout prevention, by reversing to ride the rail.