I'm not going to buy one, but I'm curious...I saw one for sale on Craigslist and did a search on it (was thinking of using it for dado cuts). Saw lots of postings about the dangers of the saw lurching towards you because of the climbing cut (even during a dado cut). So what? Not one posting explains why this situation is so dangerous on a RAS (I understand why catching wood on a table saw is). As long as you don't do something dumb like put your hand in front of the blade, the blade/head assembly will stop when it reaches the end. Isn't that end/stop collar solidly attached so there's no way the head & blade can come flying off towards you?

I've never used one--do you lean over enough so your head could get hit (and render you unconscious)?

Is the forward force so strong it can't be stopped?

I found a nice website where people listed their accidents (and exactly what they were doing and what went wrong). Half were caused by doing something dumb and most of the other half were rip or molding cuts. However, there was one crosscut where the fence split and caused a problem.

So...does someone know why all these people claim it's so dangerous for crosscuts and dado cuts?

  • This is only a guess but you know how much fun it is to have a piece of wood come shooting at you from a table saw? Now make that a sharp, spinning saw attached to a steel case (maybe). I don't want to be in the way of either, but I'd take the wood over the sawblade if I had to pick. The danger is basically losing control of a very sharp metal object that's likely headed right for your chest or arm.
    – Becuzz
    May 13 at 16:52
  • It definitely shouldn't be headed right for your chest or your arm! You should be keeping yourself clear of the tool path, regardless of the kind of saw being used. May 13 at 17:12
  • I'm inclined to vote to get rid of this one because any answer is going to be an opinion, and the nature of the question will lead to plenty of holy-war conversation. Most power tools can interact with stock in ways that are dangerous to the operator.
    – jdv
    May 13 at 17:23
  • For those who like to live on the edge and click random links to Youtube: youtu.be/TKL2ooTOPk8?t=70
    – jdv
    May 13 at 17:31
  • I didn't ask which is safer--TS or RAS, so there shouldn't be a "holy war". I'm asking what the danger is when doing a dado cut. If there is a danger, then present the fact(s). I don't see how all answers would be opinions--the danger is there or not. Having said that, I suppose someone could post opinions in a general sense without identifying the real danger--that's what I see in other forums--hence my question. May 13 at 18:21

Radial arm saws always climb-cut. This means that all that radial energy in the cutting edge wants to drag the piece into the fence; it basically feeds itself into the work, causing the operator to need to hold it back. Climb-cuts are special because no matter what the material is, the cutting edge will find a way to make it easier: climbing out of the cut and across the work. It is, obviously, the path of least resistance.

Now add a dado stack to that, with its large surface area of cutters and chip-breakers. A dado stack definitely does not want to go through the stock, when it can move only a few millimetres up and go across the stock.

The operator has to control a cutting head that wants to move toward you, and up. But the operator also has to pull the cutting head through the material and keep it in the material. These are three different directions that the operator has to guide a 3500 RPM stacked carbide cutting head through, at least two of them in opposite directions, and one perpendicular to the others. If you know anything about how humans control the forces in their bodies, you'll notice this is a Bad Idea.

This is why many woodworkers will tell you that cutting dadoes with a radial arm saw is a bad idea. The forces acting on the piece, and the requirements put upon the operator to do this safely, make for a very interesting situation. It is primarily interesting because the vectors of movement change in unpredictable ways much faster than any human can react.

There are ways to make this a less interesting situation. Make shallow cuts. Watch your feed rate. Cut thinner dadoes, or cut them in multiple passes. Engage any new-fangled safety attachments (which are all there to try and mitigate the failure modes just discussed) properly.

And assume it is going to climb up out of knot or some weird grain one day and there ain't nothing you can do about that. Any whirling blade will want to drag a hand into it, of course. The difference here is how that whirling blade wants to do it, and how you might be pushing slightly against that force when it suddenly changes direction.

The main purpose of any power tool is to separate the meat from the unwary operator. Why people specifically warn against radial arm saws and dado stacks is because there are slightly more ways for the tool to do this thing it wants to do.

We won't discuss rip-cutting lengths using a radial arm saw. There are so many better ways of doing this, and so many excellent examples showing why this is a bad idea. If you think table saw kick-back is exciting, just watch how much force can be applied to a piece of wood on a radial arm table when that radial energy is converted into linear motion.

I don't know why anyone would warn against cross-cutting. About the only thing radial arm saws excel at are being portable enough to cross-cut all day to make rafters or whatever. (Though I guess those folks would use "chop saws" which deliberately control for the problems with climb-cutting.)

In short, if you are experienced and follow the rules, accidents using power tools is a "low probability, high consequence" situation. For radial arm saws and dado stacks, people smarter than me consider it a higher probability situation with the same consequence.

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