# Box joint tear out



## otis501 (Feb 24, 2011)

I get tear out on the back side of my box joint on the table saw even when I have a backer board. 
I have a Freud dado blade and cutting ½ in oak.
What am I doing wrong or is this typical.


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## tenontim (Feb 24, 2008)

I scribe the top of the cut, like laying out dovetails.


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## TheDane (May 15, 2008)

Do you clamp the backer board and the workpiece to the jig?

-Gerry


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## Gerry1 (Jul 12, 2009)

+1 With the Dane! For sure, the backer board should solve the issue. Scribing the board is a good idea too!


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## juniorjock (Feb 3, 2008)

I've used clear tape on the back of boards and had pretty good cuts. This may be dangerous and I just don't know it….. (but I'm sure someone will tell me if it is). One thing for sure…. never but tape on a piece that is going to be a cut-off. Unless you want a piece of wood hitting you between the eyes….
- JJ


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## Finn (May 26, 2010)

Do you think the backer board has to be as hard as the board that the box joint is being cut into?


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## gfadvm (Jan 13, 2011)

You must keep your workpiece tight against the backer board or youll get tear out.I usually use eighth inch ply for a backer board.I use the Freud box joint blades and have no tearout in half inch oak.If your blades are dull or dirty this might be your problem.Hope this helps.


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## TopamaxSurvivor (May 2, 2008)

Does the Freud box joint blades cut 1/4 slots?


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## TheDane (May 15, 2008)

Topa-If he has the same set I have, the Freud cuts both 1/4" and 3/8" slots.

-Gerry


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## TopamaxSurvivor (May 2, 2008)

Thx Gerry, I remember that set now ;-)


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## wb8nbs (Jan 11, 2011)

I have good luck using 1/4 inch masonite as backer (cheap). I wet the shiny side with water and a little detergent, let that soak in a couple minutes so it's not so slippery. Have the Freud 8 inch stack dado set and because of the design of my box joint jig, I can hard clamp the the work and backer together.

http://www.flickr.com/photos/[email protected]/sets/72157622846581829/


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## otis501 (Feb 24, 2011)

Thanks guys, I use a 3/4 in backer board screwed to a board monted onto my miter gage to cut 1/4 slot. I tried the scribe and that made a big difference but still a little tear out, I will try the scribe and add 1/4 inch masonite to the backer board and give them both a try.

Thanks to all
Otis


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