# Tearout Using Stacked Dado Blade



## Tom5151 (Nov 21, 2008)

Hello all,

I am building my first kitchen cabinets and came across a little problem tonight.

Before cutting any of the dadoes, grooves and rabbets in the production wood, I decided to first do some test cuts with my dadao blade and some scraps of the maple plywood I am using for the cabinets. I am real glad I did that because I discovered I am getting some pretty noticebale tearout on the plywood. I was making about 1/4 inch deep cuts about 3/4 inches wide. I am cutting with the good side down against the table saw. My saw is a Rigid TS 3660 contractor saw.

I dont have a super great stack dado. It's a 6 inch Oshlund set that I picked up at Rockler. Do I just need a better quality blade or is there another technique that I should be using to avoid tearout? Is there an art to stacking the baldes to avoid tearout?

Thanks in advance for any help.


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## mics_54 (Oct 28, 2008)

Are you using a zero clearance plate? That might help.
I have a rather unorthodox way of dealing with tearout on routers, mitersaws and table saws but it can be SCAREY.


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## jraksdhs (Oct 19, 2008)

*it could be alot of things.....*

It honestly could just be a poor dado set. You could get it sharpened, but that could be around 40 bucks or so. I use a $100 set from HD for most of my dado and rabbet work, unless its in a high dollar sheet of plywood, then i use a forrest 8" set. You could try a very shallow pass, maybe a 1/16" just to break the veneer, then follow up with your final depth. Or you could also try taping off the cut with masking tape and using a slow feed rate. I've found that if you dont get a good cut with a normal feed rate then most likely its the dado set itself. Any more questions, please ask.

jraks


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## woodnthings (Jan 24, 2009)

*all of the above*

Cheap dado set?
It gets good reviews however! http://www.rockler.com/product.cfm?page=17335&TabSelect=Reviews&cookietest=1 I would try swapping the large blades out side to side. Assuming the tearout is only on cross grain cuts? Cheaper grade veneer plywood? Zero clearance throat plate and blue painters tape are quick cures. A quality set sounds like it's in your future! :yes: bill 
Wonder if mics54 will tell us his scary technique ......
Here's a search link: http://search.yahoo.com/search?fr=ytff1-tyc7&p=stacked%20dado%20reviews&ei=UTF-8&type=
Prices: http://www.nextag.com/stacked-dado/shop-html


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## Tom5151 (Nov 21, 2008)

Hey guys,

Thanks for the advice. I will try all of the above on some scrap stock and see what I get. 

Bill it is happening on the cross cuts. I haven't tried a rabbet or a groove yet with the grain, only a dado across the grain. The plywood is 3/4 maple hardwood veneer. It was about 50 dollars per sheet. I know that's not super great quality.

Thanks again guys. I am off to try more cuts....if that diesn,t work then would a freud set better?

Thanks.


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## cabinetman (Jul 5, 2007)

Most all of my panel dadoes are done with a router. I find it easier, faster, and more accurate with cleaner results. I use a very simple *shop made jig*. Setup is fast and accurate.

What I don't like about using the TS or RAS is that the cut is into the face, and that's where tearout can happen, along with a not so perfect bottom. Using the TS requires the panel to be held down and to the fence, and the process is hidden.


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## mics_54 (Oct 28, 2008)

nice jig cabinetman! 

Woodthings my scary tear-out prevention remediation techniques are common knowledge and I'm sure you probably use them when possible. As we all know a blade tears out less when the leading side of and blade or cutter is cutting into the wood rather than out of it. I'm sure that you for instance know that when making any edge route it helps to make the first pass letting the bit "run" from right to left rather than left to right.

Likewise on a radial arm or SCMS you can sometimes prevent tear-out by making a shallow cut across the top face on the pull and then cutting all the way through the board on the push there by always cutting the surfaces of the wood that chip out with the leading edge of the blade cutting into the board.

This is a little trickier with a piece of plywood on a table saw. It means that you would make one pass very shallow...like just through the outer veneer...from the back of the saw! SCARY. I don't recommend the practice which is why I was hesitant to suggest it.
The router is easier.


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## Gerry KIERNAN (Apr 20, 2007)

Hi Tom

You could try applying some painters masking tape to your crosscut dados. It might help reduce tear out. Another thing you coud try is scoring your cut lines with a sharp utility knife. Even a good quality dado set might give you issues when doing crosscut dados on plywood simply because you are working across the grain, and if it is going to splinter that's when it will happen.

Gerry


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## Tom5151 (Nov 21, 2008)

*Success*

Hey guys,

Well it went well this morning. I ended up running a very shallow dado first at a very slow feed rate just barely enough to cut the veneer and then finished up the rest of the depth. It worked really well. Not one hint of tearout........well so much for the test peices...here goes the production material.......I'll be back here crying if I mess it up.....LOL

Thanks again for all the tips.


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## Jacktoo (Oct 8, 2009)

The cabinet making system I was taught dose not require dado cuts and the results are perfect every time. The system uses either a Festool domino which I prefer or a biscuit cutter. The bottom shelf aligns perfectly flush with the top of the bottom rail of my face frame and the sides are also a perfect match to the face frame if you don't want a reveal on the sides of your cabinets. I can also dry fit my cabinets and set them in place before any glue is applied. This system does not require any nails or screws for assembly other than the brad nails I use on the back. This system with it's unique clamping jig is fun to use, and I feel it is far superior to any other system I have seen or read about.


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## scott lindsay (Jun 22, 2010)

cabinetman said:


> Most all of my panel dadoes are done with a router. I find it easier, faster, and more accurate with cleaner results. I use a very simple *shop made jig*. Setup is fast and accurate.
> 
> What I don't like about using the TS or RAS is that the cut is into the face, and that's where tearout can happen, along with a not so perfect bottom. Using the TS requires the panel to be held down and to the fence, and the process is hidden.


 I used a shop jig also and it worked out fine. The problem I found was that the wood thickness and the router bit did not quite match. THe board would not slide into the groove. I thought it was a little crazy because an 18mm thick board should fit into a 3/4" slot since 3/4" is more 19mm than 18mm. I like the adjustability with shims when using TS and dado blade. However I still get tearout. Have not tried the blue painters tape yet.

Scott


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