How is RAS Ripping different than a TS? Blade selection specifically.

[Nick Sorenson]

From the workpiece/board's perspective, I don't understand how it's any different ripping on a TS vs a RAS. As far as I can see, the board is being pushed into the leading edge of a spinning blade.


I ask this because I regularly see that it's not a good idea to use low tooth counts, sharp forward tooth angles, etc on a radial. I'm curious what makes ripping on a radial different than ripping on a table saw?


If anything I'd think it'd be safer to use a more aggressive blade (less teeth) due to less teeth gripping and faster/easier cut. Also there's a lot more you can do to prevent kickback on a radial (featherboards, blade guards, anti kickback pawl, etc) than you can attempt to do on a table saw.


But back to the original question, it sure seems like the board is seeing the same scenario. The one and only difference I can see in ripping is that on a radial there's support on the side of the board opposing the blade (underneath the board) whereas with a table saw there is only thin air on the side opposite the blade (above the board). I don't quite understand the difference from a purely mechanical standpoint and where it'd require use of a different blade.

Maybe the reason for a special RAS blade is for crosscutting where you'd want to avoid board lift/saw climb, or walking toward the opperator when the saw is pulled through the cut?

[Harvey Miller]

I think the forward tooth angles pull the blade along the work- that’s true for cross cuts or rips. It can cause the blade to ride on top of the wood by pushing the top down (twisting the table supports) and cause stalling, or worse, jump towards the operator.
The fear of ripping comes from a lumberyard employee ripping an piece of wood with their young child present. Apparently, the employee didn’t set the blade guard or anti-kickback pawls properly and the work kicked back. The child didn’t survive.

On a tablesaw the blade is generally set at max height where the teeth are cutting down into the work, holding it down to the table. The RAS is set with the blade cutting barely through the work (& into the tabletop), so the teeth are cutting with a shallower angle to the work- they’re cutting a longer path, more horizontally through the work, which generates more skidding force across the table.

[Jeff Duncan]

On a table saw your pushing the wood into a blade that is pushing down and back towards you. On a radial arm your pushing it towards a blade that is pushing it back and up. Outside of that I'm not sure a different blade is required for ripping? For crosscutting it's certainly beneficial to have a specialty blade. At least I notice the difference on my own saw. But of course I don't rip on the RAS as it's really just not practical in any way.

good luck,
JeffD

[Chuck Saunders]

One gives me the heebie-jeebies and the other is using the tablesaw. And I am a radial arm saw fan, just not for ripping.

[Matt Ranum]

One gives me the heebie-jeebies and the other is using the tablesaw. And I am a radial arm saw fan, just not for ripping.
Me too. I did it once when I first got my RAS and was getting used to what it can do. I decided I wouldn't do it again.

[lowell holmes]

Radial arm saw blades should have a different Hook angle on the teeth. It really makes a difference.

I don't have any problem ripping on the radial arm saw. My saw is mounted on a roll around drawer unit. I have 1X12 boards about 42 " long mounted on the sides of the saw table on door hinges.
I prop those boards up to extend the the saw table surface to about 11 feet. The board being ripped is above my waist and I use a push stick. That along with the anti-kickback palls makes it an easy cut to make. I would really have to work at it to get to the blade.

Having said that, ripping on any power saw scares me. I almost cut the end of a finger off one time on a table saw. I was ripping boards and was fatigued. I make no cuts, rip or crosscuts if I am at all tired. After that incident, I added an overhead blade guard. It cost less than the trip to the E.R.

[Dennis McDonaugh]

Isn't ripping on a RAS a climb cut like a router when you are pushing the wood in the "wrong" direction? The blade grabs and pulls.

[Nick Sorenson]

I hear some folks with the opinion that the RAS ripping is so much more dangerous than ripping on a TS. I don't quite understand where the fear comes from. Both definitely have potential to be dangerous but if the saw is set up as intended before a rip (blade guard locked so it's nose tight to the work piece, anti kickback pawl in place) and I personally also add a double clamped feather board pressing the board toward the fence, it sure seems like there's practically no way your hand/fingers can end up touching the blade.

Also, If you have it set as such it would take a TON of force to allow a board to travel backwards. I definitely can't pull it backward past the feather board clamped to the table no matter how hard I pull on the board being fed.

[Nick Sorenson]

Isn't ripping on a RAS a climb cut like a router when you are pushing the wood in the "wrong" direction? The blade grabs and pulls.

Only if you feed from the wrong direction. This would be the equivalent of feeding from the back side of a table saw (which in this case would be more like feeding a ball into a pitching machine). In the case of a radial if you did this, it'd probably bind the motor when the fed board pinched between the blade and table (but I don't plan on trying of course).

But yes, ripping on a RAS is still feeding toward the teeth hooks (facing you as you push) just like with a TS.

[Tom Willoughby]

I have never used a radial arm saw but I imagine that it is similar to a sliding miter saw but on a bigger scale. As I understand it, a positive hook angle blade on a table saw will aggressively pull the wood toward the blade but since the blade is fixed and can not move you end up feeling less pressure on the wood as you cut it through the table saw. Kind of like the hot knife through butter scenario.

The same aggressive hook blade on a sliding miter or RAS has the ability to catch the wood and since the blade can move, it can move or drive the saw toward the operator, which is dangerous. The sliding miter and RAS generally have a less aggressive hook angle blade to counteract the possibility of the saw driving the saw backward.

I will let others with more expertise chime in.

Tom

[Lee Schierer]

Mostly it is the fact that the teeth barely get through the wood and that the fences generally are not as precise as those on a TS. They recommend a negative hook angle for cross cutting to reduce the tendency for the saw to self feed when cross cutting, but hook angle doesn't make much difference on the rip cut on a RAS.

[David Winer]

"...if the saw is set up as intended before a rip (blade guard locked so it's nose tight to the work piece, anti kickback pawl in place)..."
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Amen. This is the setup recommended by instruction manuals. I've been ripping this way for over forty years without any difficulties. I imagine that alleged safety problems are the result of not following this advice.

[johnny means]

Generally, ripping on an RAS is dangerous because they are not set up with ripping as their primary purpose. Pull the RAS off the wall, move it to the middle of the floor, remove the infeed wing and you basically have a table saw with an overhead guard. But most people ripping on the RAS are just leaning awkwardly across the table with their hand and arm across the blade path.

[John McClanahan]

"...if the saw is set up as intended before a rip (blade guard locked so it's nose tight to the work piece, anti kickback pawl in place)..."
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Amen. This is the setup recommended by instruction manuals. I've been ripping this way for over forty years without any difficulties. I imagine that alleged safety problems are the result of not following this advice.

Before the internet came along, I never realized that ripping on my Craftsman RAS was so dangerous.

John

[Chuck Saunders]

If it was all I had I would use it for ripping. Having 4 tablesaws now (and 5 radial arm saws), I need help

[Dennis McDonaugh]

If it was all I had I would use it for ripping. Having 4 tablesaws now (and 5 radial arm saws), I need help

There's a 12 step process for that.

[Nick Sorenson]

The first 6 steps were to admit that you need help so you're halfway there. lol

[Nick Sorenson]

"...if the saw is set up as intended before a rip (blade guard locked so it's nose tight to the work piece, anti kickback pawl in place)..."
____________________________________________

Amen. This is the setup recommended by instruction manuals. I've been ripping this way for over forty years without any difficulties. I imagine that alleged safety problems are the result of not following this advice.

I would bet most of the ones who've taken issue with the RAS for ripping just turned the saw motor 90 degrees and went to town. I can imagine that being a scary experience.

[Terry Therneau]

One of the big differences is the lack of a riving knife. A board with tension can close up behind the blade leading to severe kickback.
Terry T.

[Nick Sorenson]

This makes sense and I definltely have had boards bind up and have wished for a splitter. Usually I've found that binding at the rear of the board will slow or stop the blade. I've yet to have a kick back but I also use preventative measures (the saw's anti-kickback devices on the blade guard and my own added featherboard against the board's edge-clamped to the table top).

[Chuck Saunders]

The first 6 steps were to admit that you need help so you're halfway there. lol


So I shouldn't have just bought 2 Powermatic 141 bandsaws? I guess that will cost me a poker chip
Chuck

[Bill White]

I ripped for years on my much maligned (but well aligned) RAS. Dados, routed, and sanded too. I guess that Board Buddies, the splitter, and all other stuff saved me.
Bill

[Dennis Ford]

Back to the original question:
On a table saw - a positive hook angle tends to pull the board down tight to the table and reduce feed pressure;
On a Radial arm saw - a positive hook angle tends to pull the board up off of the table and reduce feed pressure.

Radial arm saws should use blades with negative hook angle to prevent the board from being lifted.

[Howard Acheson]

I have used a standard 24 tooth rip blade on my RAS for the past 35 years. I've never had a problem. Just be sure to set up everything properly.

I also use my RAS for crosscutting boards to length. For that, I use a standard 50 tooth combo blade. In fact, the combo blade stays on the RAS most of the time.

All that said, I typically use my table saw for most ripping.

[David Winer]

One of the big differences is the lack of a riving knife. A board with tension can close up behind the blade leading to severe kickback.
Terry T.

The much maligned Craftsman RAS has a splitter disk that extends into the sawn kerf. Like the other parts of the ripping setup procedure, this adjustment requires the operator's attention. I always used it on my 12" Craftsman. My other RAS (Delta 14") doesn't have a splitter, but I rip with it anyway if the situation warrants (such as table saw committed to another use).

[Rick Potter]

Thanks David,

I have seen those circular discs, and it never occurred to me what they were for. Never had one though.

RP

[Lee Reep]

I've owned a RAS since 1976. Until about 10 years ago, I did not own a table saw. Did all my ripping on the RAS, with never a problem. I believe most neophytes on a RAS do not set the blade guard properly, and do not set the anti-kickback pawls. If you do this, you will be fine. I also woudl file the pawls every few years, to make sure they could grab the wood if necessary. And I always tugged the board backwards at setup to make sure the pawls would engage and hold the board.

Finally, I always used a ripping blade, just as I do on my table saw, when ripping. And a very high-tooth count for crosscutting, as you would do for a miter saw.

I am amazed at the number of used RAS's on Craigslist that have the anti-kickback pawls removed. Makes me wonder if the owner actually has them, and most importantly, tells the prospective buyer that they are required for ripping.

I no longer use my RAS for ripping, since I have a table saw. And I have a really good blade on it for crosstutting only. Properly aligned, the RAS is a superb tool to make crosscuts, and you can typically get a 15-17" crosscut with one (on a 10" RAS). Another good use is using a RAS for crosscut dadoes. For example, I needed to make dadoes for shelves on a 6 foot piece of wood that was the end of a built-in bookcase. In my opinion, there is no way to easily/safely do that on a table saw. A router could be used, but the RAS made it so simple. Cut one dado, slide the boards and cut the next one. (Yes, I did both ends together since 12" cuts are easy, and this made the end panels align perfectly for the shelves.)

If you have not guessed by now, I am a huge fan of the radial arm saw. :)

[Nick Sorenson]

Back to the original question:
On a table saw - a positive hook angle tends to pull the board down tight to the table and reduce feed pressure;
On a Radial arm saw - a positive hook angle tends to pull the board up off of the table and reduce feed pressure.

Radial arm saws should use blades with negative hook angle to prevent the board from being lifted.

That's the answer. Makes complete sense to me now. Thanks for the clarification. I had seen the hook angles addressed but never why. Valuable information here and thanks.


I have used a standard 24 tooth rip blade on my RAS for the past 35 years. I've never had a problem. Just be sure to set up everything properly.

I also use my RAS for crosscutting boards to length. For that, I use a standard 50 tooth combo blade. In fact, the combo blade stays on the RAS most of the time.

All that said, I typically use my table saw for most ripping.

Sounds like with the right setup even a ripping blade made for a TS will work on a Radial. I believe I tried a 7 1/4" 18 or 24 tooth skill saw blade on my DeWalt radial at some point and didn't have any kickbacks with the preventative measures in place. But now I see the why behind the hook angles. I'll go ahead and use the right blade. Now that I have a commercial RAS, I have the power to use just about any blade I'd guess. No reason to use the super aggressive ones anymore.