Dado stack questions

[richardrouse]

So I've never had a dado set before, I found one at a yard sale for a decent price, so I picked it up. I've always just used a router for grooves. Etc.

Finally got around to trying it out today, and was a bit disappointed in the results.

I guess my question is. Is this a set up problem or a tool problem? I've attached pictures of the stack and the resulting grooves.

[Bruce]

It looks like the blades, especially the chipper could be dull. I hope you didn't spend much on the set. Also, measure the diameter of all of the blades and chippers. They should be equal. A good sharpener can grind them all to equal diameter and sharpen them and they will be like new or better. I would suggest saving for a carbide set sometime down the road.

[dusty]

It looks like the blades, especially the chipper could be dull. I hope you didn't spend much on the set. Also, measure the diameter of all of the blades and chippers. They should be equal. A good sharpener can grind them all to equal diameter and sharpen them and they will be like new or better. I would suggest saving for a carbide set sometime down the road.

They should be equal and you can see from the cut that they are NOT. With the blades all loosely mounted on the arbor, rotate them so that the cutting edges line up and I believe you will see the problem.

[stephen_a._draper]

I see you are using a steel dado set on plywood which is the worst combination. There are three ways of doing a dado on plywood.

1. Using a radial arm saw with a steel or carbide dado set will get excellent results with no tearout on plywood. This is because the direction of the rotating teeth push down on the edges of the dado rather than pulling up.

2. Using a router with steel or carbide bits will also get excellent results with no tearout on plywood. The cut is sideways so there will be no tearout.

3. Using a table saw with a steel or carbide dado set will get poor results with steel and moderate results with carbide unless you put masking tape on the cut lines. You may need to do a shallow pass first, then a full depth pass. Cuts with the grain do not need the tape.

[wa2crk]

I would offset the outer blades a bit more. The chipper should be set between the teeth of the outer blades, as they are , but I think that I see a bit of space between the chipper and the outer blades. That should be flush.
Other than that, Dusty and Bruce are spot on.
Bill V

[Bruce]

I would offset the outer blades a bit more. The chipper should be set between the teeth of the outer blades, as they are , but I think that I see a bit of space between the chipper and the outer blades. That should be flush.
Other than that, Dusty and Bruce are spot on.
Bill V

Good eye, Bill. The bottom of the chipper blade appears to be pushing the outer blade out just a tad.

[richardrouse]

Ah! I see what you are all saying! Now I just gotta get through this shopping trip and back to the woodshop to try it out! I didn't realize that the outer blades needed to be lined up, I just knew that the chippers had to be offset from the outer cutters.

Thanks for the advice about the tape on plywood. The piece in the picture is just my practice piece. I wanted to mess with the stack a little bit before using it on my real project.. Ambrosia maple boxes with cedar or oak tops / bottoms.( I haven't made up my mind yet)