Dado question

[jheflin]

I am new to the world of cutting dado's and I have a question.
I have this HF carbide dado blade set that I picked up off of the SSUG site for $10. It's the better one of the two that they sell.

http://www.harborfreight.com/8-inch-dad ... 44566.html

It is sharp and it cuts well, but it leaves ridges in the bottom of the cut. Is this normal? Do I have the chipper blades installed incorrectly? I just randomly placed them between the saw blades. I did try to stagger the teeth, but I'm not sure how well I did.

I was watching the woodsmith shop yesterday and there fix for this was to glue a piece if sandpaper to the edge of a properly sized board and sand the ridges out. I've never seen Norm have to do this, but he uses much more expensive tools than I do.

[dusty]

I am new to the world of cutting dado's and I have a question.
I have this HF carbide dado blade set that I picked up off of the SSUG site for $10. It's the better one of the two that they sell.

http://www.harborfreight.com/8-inch-dado-blade-stack-with-c2-tungsten-carbide-tips-44566.html

It is sharp and it cuts well, but it leaves ridges in the bottom of the cut. Is this normal? Do I have the chipper blades installed incorrectly? I just randomly placed them between the saw blades. I did try to stagger the teeth, but I'm not sure how well I did.

I was watching the woodsmith shop yesterday and there fix for this was to glue a piece if sandpaper to the edge of a properly sized board and sand the ridges out. I've never seen Norm have to do this, but he uses much more expensive tools than I do.

What you are describing is pretty common with other than top of the line dado blades. To zero in on the cause I would start with only the two outer blades and cut a dado. After checking the bottom add a chipper (or two) and cut another dado. Doing this you will soon know if you have bad blades or not.

Pay attention and take your time. It is time consuming and boring but it will pay off.

BTW: Norm does not show close ups of cuts that don't work out as planned.

[ArtSale]

This problem is likely caused by the chipper blades not being all the same diameter. they should all be a few thousandths smaller than the outside blades for correct cutting.
A sharpening service would be able to correct this.

Art Sale

[robinson46176]

BTW: Norm does not show close ups of cuts that don't work out as planned.

And I firmly believe that he makes his share of those. I often observe him making a cut where I see the board lift off of the table or away from the fence by a surprising amount.

On those dado bottoms a router plane will do a nice job of cleaning them up.
http://blogs.popularwoodworking.com/editorsblog/LieNielsen+Large+Router+Plane.aspx
http://www.bob-easton.com/blog/?p=866