Why is a RAS dangerous?

[John Coloccia]

I've hear about RAS safety issues all the time, but no one ever gets into specifics. Honestly, I don't get it. Well, I get that it has a sharp, spinning blade, but almost everything in my shop has sharp, spinning blades...LOL. As long as nothing is lined up with the blade (which is generally a good idea on most power tools), what's the problem? 20 minutes of Googling just brought up more vague "RAS are dangerous" kind of links.

Maybe if I owned an RAS, or used one regularly, it would be more obvious to me. I do see that the saw wants to come towards you through a cut but I don't see that would be particularly dangerous unless you're standing right behind the saw, it knocks you over, and somehow nails you in the noggin.

Could someone give a quick overview of what makes RAS dangers unique from, say, a table saw?

[harry strasil]

People who don''t read instructions before using, and don't use common sense while using.

[Ken Fitzgerald]

IIRC...the dangers that are worried about happen when someone is trying to rip wood with a RAS.

[Bob Wingard]

RAS's aren't dangerous .. people who use them incorrectly are dangerous.

I've had one in my shop since the early 70's and on occasion, I was forced to use it for a ripping operation. THAT will get your attention, but it is not inherently unsafe to do so. Not my first choice for some operations, but then, that's why we have so many choices.

[dan sherman]

Originally Posted by Ken Fitzgerald

IIRC...the dangers that are worried about happen when someone is trying to rip wood with a RAS.

You mean cutting with the grain correct, not ripping (rough cutting) a board to length?

[Harlan Coverdale]

Originally Posted by dan sherman

You mean cutting with the grain correct, not ripping (rough cutting) a board to length?

Cutting a board to length across the grain is called crosscutting. Cutting along the length of the board with the grain is called ripping. As has been said, ripping with a radial arm saw can be dangerous if not done carefully. But then again, most other things in the shop can be dangerous if not done carefully, too.

[Denny Rice]

I have never seen anyone hurt by a RAS. I really think its much to do about nothing. RAS are no more dangerous than any other power tool in the shop. I've had one for a long time, its not the most used machine in the shop but its handy to have when needed. The last time I used mine I set up a dado blade and cut series of lap joints into 2x4's to build a new tabletop frame for my workbench. (just like uncle Norms's.) I will say cutting lap joints on a RAS vs. a table saw is much easier because you are not cutting blind, you can see the cut line because the stock is flipped over.

[jim gossage]

Ripping is the main problem - I believe that even when done "correctly", it is inherently still a little more dangerous than with a table saw for at least 3 reasons. 1) the blade is hanging from an arm with several joints, and this allows the blade to twist relative to the feed direction, whereas the TS blade is relatively immobile, 2) the RAS post that the arm is attached to is somewhat in the way of your arm when feeding wood, and 3) there is much more blade exposed above the table compared to a TS, so that if the wood gets torqued, there might be a greater chance of your hand getting thrown into the blade. I have had a good quality RAS for 15+ years and a good TS for 8+ years. After my first couple of kickbacks on the RAS, I stopped ripping with it (about 13 years ago). I have never had a kickback with the TS and rib all the time. I am probably above average in my caution in the shop, but the RAS scares me for ripping.

[Rich Engelhardt]

Hello,
The Ryobi RA200 / RA202 can come apart on you during use.
That would certainly add a lot of excitement to one's life!

[Jeffrey Makiel]

The bad reputation comes from the fact that it can be so versatile. It can cross cut, rip, shape, etc. However, it only crosscuts and dado cuts safely in my opinion. And, it does these functions as safely as any other machine. The other functions (rip, shape, etc) are too much of a compromise and best done by other means.

-Jeff

[John Coloccia]

Thanks everyone for the input. I can see where ripping could be troublesome.

[Kevin Godshall]

The biggest danger I have had from my RAS...

After making mitered cuts, I "squared" the blade back to 90, using the stop adjustment, and made several "to length" cuts only to realize my square was now about 89 degrees....... grrrrrrrrrrrrrrrr.

Now I set it to 90 and never, ever, no never move it to to anything but cut exactly 90 degrees crosscut. (I don't even like to change the height).

Dangerous.

[Rod Sheridan]

One issue not mentioned with the RAS so far is the tendency to climb cut when cross cutting.

The RAS cross cutting is the only manually operated saw I can think of where the saw blade rotation and work feed are in the same direction.

(I don't own a SCMS however I believe the correct method is to pull the saw forward, plunge down, and then traverse backwards, this is to eliminate climb cutting).

You wouldn't climb cut on a shaper without a power feeder, yet you do it every time you cross cut when using a RAS.

That's why the proper cross cut blade for a RAS has a negative hook angle, to limit the tendency for the saw head to climb over the work.

There are methods of controlling this such as hydraulic dampers to limit travel speed, or using fully mechanized travel when cross cutting.

One of the most dangerous cross cut operations is the dado, they are aggressive and have a positive hook profile, which can easily lead to a climbing situation.

People are neither very strong, nor very fast. Having the saw head suddenly change from being pulled by you, to pushing you is something a person can't cope with, in the same manner that you can't stop a table saw kickback by holding the wood by hand.

The above problems, combined with having your head down there to look at the cut lines, or having your hand or arm on the table can have nasty results when the saw suddenly starts climb cutting.

Regards, Rod.

[Doug Shepard]

I think the main problem with ripping is with the tendency of the RAS to want to lift the wood, then bad things start to happen. I quoted this from a older thread, just cuz I'm too lazy to re-type it.

Originally Posted by Doug Shepard

...
During my Jr. & Sr. year in high school I had a part time job at a local lumber yard. I can't tell you how many times I saw long (10-16') 2x10's or 2x12's kick back during ripping on a 12" RAS and go sailing out the door of the milling room. The few times the door was closed on one of these occasions, very large holes were actually made through the door. The old timers that worked there wouldn't let us kids near the thing for ripping, and after seeing a few of these incidents, I was happy to leave it to them.
...

[Fred Belknap]

I have one and it is retired to the barn. Some of the problems with the RAS was the blades that were available some years ago. They were mostly positive angle blades without carbide tips. They dulled rather quickly and the combination of dull blade and positive angle teeth would cause the saw to grab onto the work and it would run at you. If your hand was in the way it caused a serious injury. I have used mine to rip and crosscut ,also I used it to make molding. I used a wobble dado on it and it worked ok. I know two people who have been injured on a RAS, so I think it is good to use something else if you can. My biggest complain with mine was the inability to get it aligned and to keep it aligned. If I had room in the shop I would still use it sometimes. Shop is getting so that I might have to loose weight to get through it.