# Crosscutting Dadoes



## wookie (Dec 15, 2009)

Hi Everyone,

I have to crosscut some dadoes in some plywood boards that are 15 7/8" wide by 8' long on the table saw. I would like to use the fence and push them through with the mitre that also has s fence on it . I am going to square the mitre to the fence. Two guys will be guiding the pieces through. Will this work for accuracy and safety wise? Don't want to get anything in a bind. Sound good or not?

Thanks,
Jack


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## Loren (May 30, 2008)

You can do it that way but I prefer to use the fence as a stop
by attaching a board to it that stops shy of the front of the
blade.


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## sdmref (Aug 15, 2009)

Loren is on the money for the proper way to do it on the table saw, but DO NOT use the fence and miter guage together w/o a block to bump it out from the fence, you are asking for kickback if you don't use one. You can also use a router and clamp a straight edge across the board which would be much safer.


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## bigblockyeti (Sep 9, 2013)

8' is pretty wide to be going across the tablesaw, would be safer to do that on a radial arm saw. If it must be done on the tablesaw, screw an auxiliary fence to the face of the miter gauge, the wider the better. If you have a miter gauge with screws to adjust how tight it fits in the miter slot, make sure it's as tight as can be and still slide safely. Any minor slop in the fit will be greatly amplified at the end of the board. Might not be a bad idea to clamp the board the auxiliary fence on the miter gauge to further prevent movement.


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## jmartel (Jul 6, 2012)

Straight edge and a router is going to be better.


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## a1Jim (Aug 9, 2008)

I second the router and straight edge ,much easier.


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## pintodeluxe (Sep 12, 2010)

For bookshelf dados, and projects where the workpiece is long, I use an Emmerson clamping straightedge and a plunge router. I also use a shop made dado guide for custom width dados.


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## TheDane (May 15, 2008)

I would not consider using my tablesaw for this cut … what happens if one of the two guys supporting the board gets a little ahead or behind? BANG … kickback.

If you don't have a RAS, then a router and shop-made jig will get the job done quickly and safely.


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## RockyTopScott (Nov 16, 2008)

If there is a mating side (2 pieces) it might have been better to cut the dados then rip the plywood to 15 7/8.


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## bondogaposis (Dec 18, 2011)

Don't get me wrong I cut a lot of dadoes on the table saw, but in my shop I would never attempt that cut. Eight foot is too long to handle. I would much prefer to do this w/ router. RockyTopScott has the right idea too, route the dadoes then cut in half for two mating sides.


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## MT_Stringer (Jul 21, 2009)

Make an exact width dado jig like this one and get on down the road…safely. 

Hope this helps.
Mike


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## DangerDoug (Nov 22, 2013)

Radial arm saw - about the only thing they are good for.
OR router, just need to correct order bit.


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## ajosephg (Aug 25, 2008)

No way can an 8 foot board be cut accurately as described. Router with jig is the way to go.


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## waho6o9 (May 6, 2011)

Router with jig and make your cuts on the 4×8 sheet

and then rip to size, done.


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## sixstring (Apr 4, 2012)

if you have an extension wing that's wide enough to support most of the piece, build a crosscut sled deep enough to accept it. i just did this recently for a 6' long piece of 3/4 ply. in this way, i was able to safely crosscut the piece without any help. i suppose going back and forth to cut a dado makes this even more dangerous.

but yes, the router and straight edge has to be considerably safer so why take chances.


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## wookie (Dec 15, 2009)

Thanks, guys. This why I put up this post. I was out voted on cutting the dados first then ripping to width.


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