The Ultimate Sawsmith Radial Arm Saw Thread

[dusty]

I found this. A partial answer to my question. Thanks for the alert.

http://www.rockler.com/how-to/blades-fo ... miter-saws

And then there is this which I found most informative:

http://justsawblades.com/ten/choosing_t ... blade.html

[Kidsmoke]

this is great information. count me as another newly informed on this topic!

[JPG]

Sweet!

The castings look nice and beefy. In the early 60's, after Black and Decker acquired Dewalt, they quickly started changing the saw designs to reduce manufacturing costs, and sacrificed rigidity and repeatability in the process. Which ultimately led to a huge decline in RAS popularity. I'm curious as to how the Sawsmith's rigidity compares to the Dewalt's of the period.

BTW, you probably already know this, but for the sake of anyone else who might read this thread, DO NOT use a standard table saw blade on a RAS. That can be very dangerous.

NO, I did not know that and though I have now been properly warned - please explain what makes this hazardous? How does a RAS blade differ from a regular saw blade?

The 'hook' angle needs to be negative. Otherwise it is too aggressive and will climb(you have to hold it back(push) rather than 'pull' it through the workpiece).

[BuckeyeDennis]

Conventional wisdom is that RAS's need negative-hook blades. As JPG pointed out, a normal RAS pulling crosscut is actually a climb cut. Most tablesaw blades are too aggressive for such a cut. And a push cut is dangerous, as the blade wants to lift the workpiece and throw it over the fence.

The host of the Dewalt radial arm saw forum has worked with Forrest on RAS blade testing. He has found that a rather small positive rake gives the best results. For anyone who wants to dig further, this thread from their FAQ list gives specific blade recommendations, and considerable discussion.

In late-breaking news, the top-rated blade, a Forrest WWI TCG (a.k.a. Mr. Sawdust blade) can now be ordered online from Sliversmill.com. Just be sure to get the TCG version.

[JPG]

I should have said 'hold it back' rather than 'push'.

[BuckeyeDennis]

I should have said 'hold it back' rather than 'push'.

That's how I read what you wrote in the first place. I simply wanted to warn anyone who might use a RAS without proper instruction. Some folks believe that starting a crosscut with the RAS carriage extended, and then pushing it back through the wood, is the correct way to crosscut with a RAS. That does avoid the climb cut. But it's a dangerous cut for a different reason, unless you have the workpiece clamped down.

[JPG]

I should have said 'hold it back' rather than 'push'.

That's how I read what you wrote in the first place. I simply wanted to warn anyone who might use a RAS without proper instruction. Some folks believe that starting a crosscut with the RAS carriage extended, and then pushing it back through the wood, is the correct way to crosscut with a RAS. That does avoid the climb cut. But it's a dangerous cut for a different reason, unless you have the workpiece clamped down.

I do not have sufficient knowledge to understand why that is a good practice with a 'sliding' rotary miter saw.

Pulling/climbing creates a downward and rearward force to the workpiece that tends to keep it in place.

Pushing creates a rearward and upward force. Not stable methinks.

Now if the blade were rotating in the opposite direction it creates a downward force, but also outward(towards the operator).

Like I said I simply do not understand the philosophy other than it is 'different' from that 'dastardly unsafe ras'.


Somebody enlighten me with concrete facts(no rationalized hypothesis please).

[BuckeyeDennis]

Good question. I just studied the manuals for three major brands of SCMS's. They all warn against pull cuts (due to the potential climb / run-out hazards), and advise push cuts. However, they all state, with varying degrees of emphasis, that the workpiece should be clamped down before doing a sliding/push cut, to avoid the lifting problem. And they all provide convenient clamps to do exactly that.

That makes sense, as following that procedure avoids both hazards. But I don't recall ever seeing anyone use said clamps on TV.

So my take-away is that SCMS's have exactly the same cut-hazard issues as a RAS.

[JPG]

Good question. I just studied the manuals for three major brands of SCMS's. They all warn against pull cuts (due to the potential climb / run-out hazards), and advise push cuts. However, they all state, with varying degrees of emphasis, that the workpiece should be clamped down before doing a sliding/push cut, to avoid the lifting problem. And they all provide convenient clamps to do exactly that.

That makes sense, as following that procedure avoids both hazards. But I don't recall ever seeing anyone use said clamps on TV.

So my take-away is that SCMS's have exactly the same cut-hazard issues as a RAS.

Slightly different(sorta).

Pull climb causes potential aggressive self feeding(advancing towards operator).

Push plow causes workpiece to raise. Maybe considered the lessor of the evils that is possibly overcome with PITA anti raise clamps.

I agree this is a procedure distinction, not a machine distinction.

So I will continue pulling regardless of the tool.

Miter cuts are to be done carefully!!!

[Skizzity]

While I don't know if it is "correct", I have always used the out-down-and-back technique with my SCMS. Meaning: out-1/8" score along the top, down- plunging the cut in the front of the workpiece and back- finishing the cut while pushing back to the fence.