# Need advice on cutting dadoes in plywood.



## TheChadshowalter (Apr 16, 2014)

I am attempting to cut a dado in maple veneered 3/4 inch plywood. I am using a mibro set and if I am going with the grain it is flawless. When i cross the grain things do not got well at all… I am new to woodworking >1 year and this is my first project for my wife to convince her the table saw she bought me was well worth it. and pointers would be appreciated.


----------



## j1212t (Dec 7, 2013)

Try scoring the dado lines with a marking knife before you go at it, otherwise your plywood will tear like crazy, especially going across the grain.

Scoring the dado lines before will eliminate that problem. That's what i did anyhow.


----------



## PaulMaurer (Feb 22, 2014)

Scoring is your best bet. Of the other things that help, a zero clearance insert or a zero clearance table saw sled are both good. With it you might try a shallow first pass (like the thickness of the veneer)- scoring with the table saw blade or packing tape along the cut line. 
"Scoring the dado lines before will eliminate that problem"(jake) If it dose not, then you probably have not cut deep enough or something is out of alignment.


----------



## lab7654 (Mar 31, 2012)

ZCI's help quite a bit, and a shallow cut will also reduce the tear out. Most dado stacks make "bat ears" in the top of the cut in the corners, and with a skimming cut they will do the scoring for you. The Freud stack I use has given me very little tear out so far even without taking the skim cut, and I'm very pleased with it.


----------



## wapakfred (Jul 29, 2011)

The scoring pass idea might be the easiest, though all of the ideas above should help. Slow down your feed rate a little and see if that helps as well. Cross grain cuts on plywood can always be a pain, the veneers of today are so thin it's very tough to do. I'm not familiar with the Mibro dado set, but give some thought to upgrading yoru set if this will be something you will be doing a lot.


----------



## squaretree (Feb 5, 2014)

+1 for zero clearance, scoring and shallow cut. I'm in the middle of a cabinet build myself (oak veneered ply). I used my dado stack for some cuts, and used my router with an exact-width dado jig for cross-cuts on pieces that were too large to run across the tablesaw safely. The jig makes it super easy because you can actually use the jig as a guide to score both sides of the cut. Just don't tell the wife you used a router


----------



## TheChadshowalter (Apr 16, 2014)

Tonight, I shall try scoring…. today I will look for an upgrade on dado blades. Mibro was a box set purchased at lowes several years ago I just finally got a saw that will run them! I also use my router to do some dados I just have a cheap bit and and that needs upgraded also… the joys of just starting out.


----------



## Vincent (Mar 10, 2009)

Scoring (sharp utility knife) and ZCI works for me.


----------



## HorizontalMike (Jun 3, 2010)

Here is how I cut dados into my 3/4" Maple plywood using a router and a shop-made router based dado jig:

The best part about this jig is that it adjusts to the exact size of the piece you want to insert in the dado.


----------



## TheChadshowalter (Apr 16, 2014)

what is ZCI?, never mind i figured it out…


----------



## pintodeluxe (Sep 12, 2010)

My Freud dado set will cut grooves and dados in plywood without any splintering at all. I do use ZCI's, but never bother with scoring cuts. I think it boils down to tooth geometry. You need a good dado set that features angled teeth on the outside cutters. Orient the cutters so the outside blades make square shoulders, and the angled teeth face inward toward the chippers. Does your dado set have angled teeth?

To be 100% honest with you, years ago when I used a dado blade for the first time, I put the blades on backwards. It actually still cut a dado!


----------

