Replies

1. 
   nazard | Jun 19, 2007 10:30pm | #1

   A back-up board screwed to your miter gauge would be a good start.  Also, clamping the workpiece firmly to the backer board if necessary.

2. 
   colebearanimals | Jun 19, 2007 10:51pm | #2

   Hi kummell,

           You could also score a line on the backside of your workpiece ( exit side of your cut )with a knife at the depth that your dado is cutting.

                                                   Paul

3. 
   Lataxe | Jun 20, 2007 04:35pm | #3

   K,

   Using a router table with sliding xcut carriage, rather than a TS, I find that the secret of preventing tear out is to ensure you use the end grain of some hard, dense wood as the backer board.  Beech or hard maple are very good.  I imagine the mechanics of tear out prevention are just the same with TS-cut finger joints.

   Hard wood end grain resists spelching or other degradation much better than long grain or even the end grain of more spongy timbers such as pine.  The backer boards not only give clean finger joints but also need renewing much less often.

   Lataxe

1. 
   kummell | Jun 20, 2007 04:49pm | #4

   thanks Lataxe...  from reading that, I gather that you don't need to have a fresh piece of backer board behind each finger/cut?

4. 
   BruceS | Jun 20, 2007 05:46pm | #5

   When doing box joints I stack and clamp all four pieces together ( two of them offset the width of a pin) and run all four at once, with a backer.  Much less room for error that way and no tearout.

   Work Safe,  Count to 10 when your done for the day !!

   Bruce S. 

    

1. 
   kummell | Jun 20, 2007 06:39pm | #6

   I never thought about running all 4 sides at once - what a great idea!   and an easy modification to my jig...

1. 
   BruceS | Jun 20, 2007 06:57pm | #7

   Four at once,  Just be sure your set up is dead on.  No need for four pieces of scrap, been there.  I also make the pins about 1/32 long and sand them off after the glue-up.Work Safe,  Count to 10 when your done for the day !!

   Bruce S.