Why are dado blades outlawed in some parts of the world?

[Mike Mason]

Why are dado blades outlawed in some parts of the world? I use one from time to time, and I really don't think it is any more dangerous than a regular saw blade. When cutting with the grain, I have the ratcheting, spring-loaded hold down wheels on my rip fence, and I always use push sticks or rubber-padded masonry floats to feed the wood, and my hands are never over the dado or saw blade or even past the front edge of the blade. When cutting a true dado (i.e., cross grain), I use a good quality miter gauge and keep my hands well away from the blade.

Is it because a person might try to cut an 11/16" deep dado in a 3/4" board, leaving very little strength in the board after the dado is cut, which can lead to kickback?

I'm really curious as to how a person is in more danger with a dado blade than with a regular saw blade...

[Lee Schierer]

Mostly because cutting dados does not allow the use of a riving knife.

[Mike Mason]

Mostly because cutting dados does not allow the use of a riving knife.

I suppose that must be the case, but I thought that the main function of a splitter or riving knife is to prevent pinching of wood on the back of the blade and the resultant kickback potential if any internal stresses are relieved when ripping through a board. When using a dado set to plow a groove, the wood is not cut through, and unless the dado depth is a very high percentage of the board thickness, pinching seems unlikely since there is a web of material that prevents that from happening. It seems to me that a dado set is less likely to result in pinching/kickback than a regular saw blade, especially if one uses proper methods of holding the work down and against the fence. Maybe the splitter or riving knife serves other functions as well?

[Lee Schierer]

I suppose that must be the case, but I thought that the main function of a splitter or riving knife is to prevent pinching of wood on the back of the blade and the resultant kickback potential if any internal stresses are relieved when ripping through a board. When using a dado set to plow a groove, the wood is not cut through, and unless the dado depth is a very high percentage of the board thickness, pinching seems unlikely since there is a web of material that prevents that from happening. It seems to me that a dado set is less likely to result in pinching/kickback than a regular saw blade, especially if one uses proper methods of holding the work down and against the fence. Maybe the splitter or riving knife serves other functions as well?

It also prevents the wood from getting caught on the top of the blade should it ride up or otherwise be lifted off the table while the cut is being made.

[johnny means]

I suppose that must be the case, but I thought that the main function of a splitter or riving knife is to prevent pinching of wood on the back of the blade and the resultant kickback potential if any internal stresses are relieved when ripping through a board. When using a dado set to plow a groove, the wood is not cut through, and unless the dado depth is a very high percentage of the board thickness, pinching seems unlikely since there is a web of material that prevents that from happening. It seems to me that a dado set is less likely to result in pinching/kickback than a regular saw blade, especially if one uses proper methods of holding the work down and against the fence. Maybe the splitter or riving knife serves other functions as well?

The main purpose of a riving knife is to prevent th peice from rotating into the blade. Pinching onto the blade isn't the issue many think it is.

[mike calabrese]

Mainly for safety kick backs serious hand injuries.
In Europe the table saws sold have a arbor that is just long enough to mount a sw blade. You could not install a dado set if you had one .
https://www.quora.com/Should-table-saws-fitted-with-dado-blades-be-illegal-in-the-United-States-considering-they-are-already-banned-in-the-United-Kingdom-and-Europe

mike calabrese

[Mel Fulks]

Some wood will close up a little and can kick back. But sadly ,it doesn’t happen enough for guys to get used to it . I only had that happen
a couple of times in many years of working. I think it’s best to make them as shallow as possible for the job , not 1/3rd or some-such.

[Richard Coers]

From what I have read it is not illegal. For those saying it is, a link to the law should be available on the internet. I can't find it.

[Jim Dwight]

I can, unfortunately, testify that kickback is a very real possibility with a dado blade. The middle finger on my left hand was broken and I got a cut that needed six stitches to close and the finger will never be the same despite the fact that I was using my SawStop PCS. My stupidity caused the kickback but when the block of wood I was holding over a dado stack as I raised it through the throat plate twisted, the wood violently pushed my finger into the dado blade. This was an unusual incident but I think most kickbacks are from wood moving away from the rip fence and moving into the blade sideways or from a similar lack of straight movement through the blade when cross cutting. When the wood moves sideways into the blade, it is violently jerked by the blade and bad things happen.

Dado cuts are made without the riving knife nor will most blade guards work when making a dado cut. So the dado stack is exposed except in many cases it is covered by the workpiece. Obviously it is not terribly dangerous, I have done it many times without issue, but I think it is a more dangerous cut at least in some ways than other uses of the table saw.

I suspect that Europe prevents sales of saws that can accept dado blade stacks rather than prohibiting woodworkers from using dado stacks. Accomplishes the same thing and it is easier to administer.

[Kevin Jenness]

A wide dado set takes a bigger bite with more "traction" and more kickback potential than a single blade. European safety standards are more restrictive for hand fed operations in general.

[Mel Fulks]

Might be that beginner environmentalists have confused dados with do-do’s, ( funny look birds) And when they find out the do-do’s are all dead ….there could be trouble ! Might be some riled-up “volunteer groups” .

[Mike Cutler]

From what I have read it is not illegal. For those saying it is, a link to the law should be available on the internet. I can't find it.

Richard
I don’t know that you will find “a law”, but in their version of our OSHA, and consumer protection, regulations, you might find the definitions of what makes it unacceptable.

Any one here know what machine they use in Europe, or the UK, that replicates a dado, as made in the US?

[Rich Engelhardt]

Table saws in Europe are required by law to stop in 10 seconds or less.
They haven't managed to accomplish that with a dado blade yet, so, they make it next to impossible to use one.

It's covered in this post from 2009:
https://sawmillcreek.org/archive/index.php/t-102657.html

[Jim Dwight]

I still haven't purchased another dado blade set. I make dados either by repeated cuts with my normal table saw blade or with my router with my track saw track guiding the router. A router doesn't have the power of a table saw but it works great for the shallow dado cuts I normally make.

[Ron Citerone]

I had a near miss with a dado kickback years ago. I still use them occasionally, but use a router mostly now.

[Mel Fulks]

A “single flute” router bit will cut much faster than the standard “double flute”. I worked in some shops that did not have any single flute
bits ! What a waste of time.

[Mike Henderson]

I had a near miss with a dado kickback years ago. I still use them occasionally, but use a router mostly now.

I do the same. I find I get better dados with a router than with a dado set.

Mike

[Ola Carmonius]

Dados are not forbidden in europe, an hobbyist can use whatever he wants in his garage shop. In commercial use they are forbidden.

The dados results in that the saws safety features (break, riving knife, blade protection in cases without overam blade guard) are comprimised. So, they can't sell a saw blade that doesn't fulfill the saws safety rules.

[Curt Harms]

I do the same. I find I get better dados with a router than with a dado set.

Mike

Yup, cleaner bottoms and with the right jig, the width is always dead on due to using a piece of the material that's going to fit in the dado to set the width. Using a router is slower with the setup time but for a hobby shop I don't think enough to matter.

[Doug Garson]

the width is always dead on due to using a piece of the material that's going to fit in the dado to set the width.
I understand how you can do this with a dado stack and shims, how do you do that with a router bit?

[Mike Henderson]

I understand how you can do this with a dado stack and shims, how do you do that with a router bit?

I take two straight pieces of wood and clamp them into place where I want the dado, with the piece of wood that's going to fit into the dado between those two pieces of wood. Then I route using those two pieces of wood as a guide. Gives me an exact width opening. I do have to adjust the bit for the depth.

Mike

[Rich Engelhardt]

I understand how you can do this with a dado stack and shims, how do you do that with a router bit?
https://youtu.be/LhZSS-VFf6Y

Tamar does a nice job.

[Doug Garson]

I take two straight pieces of wood and clamp them into place where I want the dado, with the piece of wood that's going to fit into the dado between those two pieces of wood. Then I route using those two pieces of wood as a guide. Gives me an exact width opening. I do have to adjust the bit for the depth.

Mike
OK,I was thinking you were doing it in one pass in which case the bit would have to be the exact width of the dado. I assume you use an edge trim or pattern bit. Good way to do it. There are several designs of jigs for that method.

[Mike Henderson]

OK,I was thinking you were doing it in one pass in which case the bit would have to be the exact width of the dado. I assume you use an edge trim or pattern bit. Good way to do it. There are several designs of jigs for that method.

Yeah, it usually takes several passes with the router. Depending on the dado, I may not cut to full depth the first pass. So the router is slower than a dado blade, but I'm not cutting a bunch of dados. I'm doing some piece of furniture and there's not that many dadoes to cut on it. Also, I do it for a hobby so the extra time is not that important to me.

This approach does give a very well fitting dado.

Mike

[Ron Citerone]

I understand how you can do this with a dado stack and shims, how do you do that with a router bit?
Doug, I usually use a 1/4 or 3/8 dado half the depth of a furniture side for instance. Then I cut a rabbet on the end of the shelf or web frame to fit the dado. I use same thickness scrap and sneak up on it and then run all the shelves and web frames.

I find this makes a stronger joint because of the shoulder. My glue up results come out way nicer this way too.

[Derek Cohen]

My European-built Hammer K3 came with a fitting for a dado (but no blades). The desire to cut a dado on a tablesaw has never interested me, although I can see the value of a dado set for removing tenon waste.

The issue I have with a dado blade is that panels (or whatever else are fitted into the dado) are unlikely to be a standard size/one size fits all, and the match will never be as good as either a router set up (as Mike alluded to) or, my preference, using a chisel and router plane (once each board is measured). Of course, this is for one-off pieces of furniture, and quite uneconomical for production work (where provision would be made for exact fits).

Regards from Perth

Derek