WWA Info Exchange

I have been trying to cut some box joints and am getting a lot of tear out. I am using a brand new Freud dado set and built a box joint jig. I'm getting a good fit between the fingers, but the backside of the joint keeps tearing out. The jig has an opening that is exactly the size of the area being cut, so it should be supporting the workpieces. I've tried going fast, slower, and very slow. I've tried removing the workpiece after it passes the blade and have tried dragging it back across the blade before removing the workpiece. Nothing seems to be working.

I'm using maple that is approximately 1/2" thick, so the cuts are approximately 1/2" deep. They are 1/2" wide also.

Any thoughts on a solution would be appreciated.

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John

Too many possibilities ....... hard / soft maple? ...... grain orientation ? (ie 1/4 sawn / flat sawn etc)

Couple quick suggestions, use backer board, score exit point first.

Try scoring the exit points with a sharp marking knife, as mentioned above.

Good luck.

James

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The ancient Greeks and Romans used raw talent and man power I use all the help I can get from Mr. INCRA, Mr. Swissmade, Mr Grizzly and all fellow woodworkers. All fine souls if I say so myself.

I would suggest a scrap backer.
Are you cutting one side of the box at a time or stack cutting 2 or more sides at once? (I usually clamp the front and back together or the two ends and cut two at a time.) You may get some tear out but, only on one piece and if you use a piece of thin plywood as a backer you will probably save both pieces and they should match fairly well.
If you orientate the pieces corectly, the tearout should be on the inside of the box and alot easier to hide.
Sometimes poo poo just occurs. The true test of a good wood worker is the ability to hide the goofs.
I don't make mistakes, I just have design changes once in awhile.

Rog

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An ounce of responsibility is worth a pound of State and Federal laws.

I spent most of my money on woodworking
tools and beer, the rest I just wasted.

You might have some "heel" in the setup. You have to be perpendicular to the blade and move parallel to it. Backer boards are a good idea, but won't compensate for this, or for any arbor excentricity. One of the many good reasons for going to a router jig with a spiral bit. http://us.oak-park.com/catalogue.html?list=boxj-- and look at the demo.

I don't cut the mating pieces simultaneously, prefering to use a spacer as in the combination joint to make the gap-first cut, and the no spacer for the pin first. One less thing to go wrong, in my opinion.