Can a combo blade rip without burning?

[Dave Cullen]

I have a 10" CMT thin combo blade on my 1 hp saw that I use for everything. It's served me well for about 10 years but lately I've been ripping 1-1/2" maple and I'm getting saw marks and burning. I think the tooth configuration is 4+1.

A lot of people recommend the Diablo 50T combo, yet I notice they are just ATB. Can a blade like that actually rip hardwood?

I'm torn between getting a different combo blade vs a dedicated rip blade. I know if I have to change blades between operations it'll get old quickly.

[glenn bradley]

Just so you know where I am coming from . . . I change blades frequently based on operation and desired result. I can change a blade faster than I can get a cup of coffee or go to the bathroom so I consider this a non-issue as it can be accomplished in about a minute.

That being said; I have a 50 tooth 4+1 that rips 1-1/2" stock without much issue. Maple, cherry and others are burn prone and of course, stress release can cause more or less burning depending on what happens. I generally reach for a 30 tooth "glue-line" rip when ripping in general but, will grab a 24 tooth FTG for thicker or burn prone material.

[Rod Sheridan]

In my opinion, at about an inch of thickness, you need to change to a rip blade.

I don't know why you think it will be a bother, do all your ripping at once and you won't be swapping blades.

I put the rip blade in the saw, and croscut to oversize length, joint and plane 2 faces/one edge and then rip to width.

At that point I change to a crosscut blade and complete all the other sizing operations............Regards, Rod.

[johnny means]

I think all combo blades should be lined up and shot. But seriously, besides doing nothing really well, what is the upshot to combo blades?

[Phil Thien]

I've never noticed a difference between a sharp combo blade and a sharp rip blade. Actually, I take that back, I have some combination blades that will rip faster than any rip blade I've got.

[Lee Schierer]

I also change blades frequently and don't own any combination blades. However, you indicated that the blade in question used to do a decent job. I suspect that it may be time to get the blade sharpened and to check your saw for proper alignment. As a first step take the blade off and soak it for about 5 minutes in sudsy ammonia and then brush the teeth with an old tooth brush. The accumulated pitch on the teeth may be the majority of your problem.

[Chris Fournier]

It sure can. I never bought into the thin kerf thing though so all of my 10" blades were heavy. My planer or combo blade worked very well for ripping but if I knew that I had a bunch of ripping to do I put a rip/glue blade on the saw. Very quick and best results for the task, also easier on the motor.

[David Kumm]

Depends on the saw too. A good saw with little runout and a stiff blade of 40 teeth or less will handle most wood. Key is enough power to keep the stock moving through the cut without having to slow down and a well set up fence. Sounds like your blade is getting dull. Doesn't take much with a 4=1 to as the teeth are heating up in the cut and wear more quickly or at least build up resin which does the same thing. Dave

[Lee Reep]

My 1.75 HP contractor table saw just got a Forrest thin kerf 30 tooth blade. It is an absolute joy to rip with. I have not tried cross cutting with it, preferring my radial arm saw for crosscuts. But the Forrest website does say that the Woodworker II can be used for crosscutting as well as ripping. I called Forrest before buying, since they have both a 30T and a 40T Woodworker II blade and I wanted more clarification from them on recommendations.

I wanted to rip thicker stock, but just could not power thru thick woods without burns. The Forrest blade goes thru 8/4 oak effortlessly. They are expensive, but worth every penny in my mind. I was going to buy a 3 HP SawStop PCS and have delayed that for awhile, since this blade has breathed new life into my saw.

[Kevin Womer]

Does the blade have pitch buildup on it? Have you had it sharpened recently? Those factors aside you should be able to rip 1-2 inch hardwood with few problems.

[Rod Sheridan]

Phil. there's something wrong with your rip blades or saw setup.

A rip blade is substantially faster at ripping than a combination blade.

You'll really see the difference when you use the saw with a feeder, typically most people don't feed a rip blade fast enough..........Rod.

[Nathan Callender]

For thick stock get a 24 tooth ftg blade and you will be amazed!

[scott spencer]

After 10 years is there any chance your CMT blade has become dull and/or dirty? The Freud Industrial, Irwin Marples, Infinity Combomax, and Tenryu RS25550 are all ATB/R blades if you're interested in replacing it with a comparable design.

With that said, a good 24T dedicated rip blade should be considerably more efficient at ripping than a 50T combo or 40T general purpose blade....it's simple physics, as is the rougher cut it leaves, though many are marginally capable of leaving a glue line edge.

[Larry Frank]

I do as some others keeping a good rip blade on the saw for both ripping and rough cross cutting. I change over to a cross cut for final length cuts. I also have a high ATB blade for plywood.

I am surprised to hear that anyone would comment that their combination blade rips would better than a rip blade. Something sounds a miss.

[Phil Thien]

Phil. there's something wrong with your rip blades or saw setup.

A rip blade is substantially faster at ripping than a combination blade.

You'll really see the difference when you use the saw with a feeder, typically most people don't feed a rip blade fast enough..........Rod.

LOL, I respectfully disagree.

I used to notice a big difference back in the day when I used steel (non-carbide-tipped) blades.

With carbide, not so much.

PLEASE ANYONE READING ROD'S POST: There may be a tendency for someone reading that to try pushing stock into a rip blade faster than they're accustomed to doing so, to see how it works. Don't.

[Phil Thien]

After 10 years is there any chance your CMT blade has become dull and/or dirty? The Freud Industrial, Irwin Marples, Infinity Combomax, and Tenryu RS25550 are all ATB/R blades if you're interested in replacing it with a comparable design.

With that said, a good 24T dedicated rip blade should be considerably more efficient at ripping than a 50T combo or 40T general purpose blade....it's simple physics, as is the rougher cut it leaves, though many are marginally capable of leaving a glue line edge.

Please explain the simple physics.

[scott spencer]

If all else is equal, fewer teeth means less resistance and a more aggressive cut.

[Clint Olver]

Since I got my Infinity combo blade http://www.infinitytools.com/10-Combination-Saw-Blade-50T-5_8-Arbor-125-Kerf/productinfo/010-050/ , I haven't used my dedicated rip or cross cut blades. I have a 40T CMT blade too, it was okay, but not as good as the Infinity. Of course, if your blade isn't sharp, it won't be good at anything.

C

[Rich Engelhardt]

I find it far easier and quicker to change blades and eliminate burns marks that it is to deal with the burn marks once they are on/in the wood.

[Phil Thien]

If all else is equal, fewer teeth means less resistance and a more aggressive cut.

But if all else is equal, the blade with fewer teeth is taking "bigger bites" which increases resistance.

[Matt Meiser]

I use a 40T combo blade almost all the time but if I'm ripping something that thick I switch to a rip blade.

[Ray Newman]

"...far easier and quicker to change blades and eliminate burns marks that it is to deal with the burn marks once they are on/in the wood. "
--Rich Engelhardt

BINGO!

[Bill Huber]

I have had a few different combination blades and have not really been very happy with them in the area of ripping. I got a Guhdo Gmaxx at the woodworking show and I am hook on the Gmaxx blade. The cuts are very clean and smooth, I was really happy with the smoothness of the cut.

It is a 50 tooth, ATB, carbide tipped glue line general purpose blade and it rips just about as good as my 24 tooth rip blade. On top of how good it works it is cheap when you look as some of the others out there.

http://www.amazon.com/Guhdo-Gmaxx-Series-2400-100A50-Circular/dp/B0060H1MDG

This is my go-to blade now on my little Jet table saw.

[johnny means]

Not true. The mechanics of ripping versus cross cutting are very different. When ripping, the material tends to want to cleave with the grain. This causes the chips to come if the board in a ribbon shape. Picture the way a hand plane creates a long shaving. This shaving is then forced into the gullet. Less teeth equals larger gullets which allows the tooth to make it through the cut without clogging up. This shaving action actually does create more resistance on a single tooth. Teeth spaced further apart allows for less actual cuts to be happening at any given moment. The most simple way I can describe the difference between ripping and crosscutting is to compare it to cutting firewood. How much effort does it take to cut down a 1ft diameter tree? How much much easier is it to split a 1ft long log?

[David Weaver]

A simple smoothing plane solves the burn problems. Very little work, and no change more than a couple of thousandths in the width of the board - something you'd probably solve more unevenly by sanding, anyway.

[Chris Fournier]

But if all else is equal, the blade with fewer teeth is taking "bigger bites" which increases resistance.


Yes but no. Grain orientation which is really the heart of the matter is the practical variable all things being equal or not and cross cutting vs ripping are two different games. If we are talking about ripping, the limiting factor to feed speed is the clearance of the "shavings" vs the "chips" that you get from cross cutting. A proper ripping blade has a different tooth configuration of course and a gullet that can transport the large volume shavings.

[Phil Thien]

Yes but no. Grain orientation which is really the heart of the matter is the practical variable all things being equal or not and cross cutting vs ripping are two different games. If we are talking about ripping, the limiting factor to feed speed is the clearance of the "shavings" vs the "chips" that you get from cross cutting. A proper ripping blade has a different tooth configuration of course and a gullet that can transport the large volume shavings.

Nobody here hand-feeding stock is packing gullets. Well maybe if you're cutting 2.5"+ material with a strong saw and maintaining a fast feed rate, you could pack a combination blade's gullets. But you'd have to be feeding pretty darn fast.

[Chris Fournier]

LOL, I respectfully disagree.

I used to notice a big difference back in the day when I used steel (non-carbide-tipped) blades.

With carbide, not so much.

PLEASE ANYONE READING ROD'S POST: There may be a tendency for someone reading that to try pushing stock into a rip blade faster than they're accustomed to doing so, to see how it works. Don't.

What saw do you use Phil? What blades? I would agree with Rod, a rip blade rips faster than a combo blade, you can feed it faster than a combo blade, it is after all designed for ripping and the cutting geometry and gullets are designed to "plane" wood and extract the rather large shavings efficiently, a combo blade can't cut as efficiently nor remove the swarf as well.

[scott spencer]

But if all else is equal, the blade with fewer teeth is taking "bigger bites" which increases resistance.

Think of it this way....the teeth create friction when contacting wood at high speed....more teeth creates more friction. "Bigger bites" is really a function of feed rate....if the feed rate remained the same, the blade with fewer teeth has less resistance and runs cooler. The combination of having fewer teeth making less contact and efficiently removing the material from the kerf (less resistance and heat), actually allows for a faster feed rate.

[Larry Edgerton]

I have 4 saws, so I will usually have a combination blade in one of them just for convenience. But....

Same saw, 4 hp, same wood, same power feed, both FS Tool blades in new condition, I can not run as fast a speed on the feeder with the combo blade, and the rip blade gives a better cut.

Sorry Phil, you are just wrong on this one.

Larry

[Chris Fournier]

Nobody here hand-feeding stock is packing gullets. Well maybe if you're cutting 2.5"+ material with a strong saw and maintaining a fast feed rate, you could pack a combination blade's gullets. But you'd have to be feeding pretty darn fast.

I used a 3hp General 350 and would resaw up to and over 8/4 pretty regularly Phil and depending on the species and grain run out I would get packed gullets on occasion. I fed by hand at a pace that made the best finished surface. You don't have to be feeding fast at all.

[Phil Thien]

I have 4 saws, so I will usually have a combination blade in one of them just for convenience. But....

Same saw, 4 hp, same wood, same power feed, both FS Tool blades in new condition, I can not run as fast a speed on the feeder with the combo blade, and the rip blade gives a better cut.

Sorry Phil, you are just wrong on this one.

Larry

First, I think it is interesting that I have to be wrong for you to be right. I don't want to fight anyone, just tell people what I've observed, and maybe ask some questions that will make people think a little bit.

First, let's examine the typical blade thread on this forum. Guy shows up and says he is having trouble cutting some thicker stock with a blade that has been working fine for several years. People nearly unanimously say "well that is because you're using a combination blade, get a rip blade for ripping that thick stock." Some people mention that they insist on switching blades each time they switch cutting operations (rip for rips, cross-cut for cross cuts).

So the guy goes out and buys a new rip blade, rips his stock, and reports back that "boy, it really did the trick, easy to feed and no burning." And now he is a convert. So the next time the same sort of thread appears, he chimes in as part of the choir and the pattern continues.

Never do people say "try a new sharp blade, any blade that is new and factory sharp." I think if people did try a brand-new combination blade, they'd find it does a pretty good job, even ripping 1-1/2" stock.

But the comparisons always boil down to a used, dull combination blade to a new sharp rip blade. Apples to oranges.

People are so inclined to simply repeat the gospel without even stopping to consider the rather easy concepts, that it is really amazing to me. People keep mentioning the larger gullets on rip blades. Well, a typical cabinet saw spins the blade at 3000-RPM's. That is 50 times a second, guys! I'm not going to compute gullet volumes (but there are actually books for sawmill operators that go into this, you can find them on google books), but do you realize what it takes to fill the gullet of a blade spinning 50 times a second? A feed rate none of us are going to encounter unless the stock is very thick, the feed rate is very fast, and the motor very strong. Factories worry about gullet loading, not guys puttering around in their shops making a kitchen full of cabinets.

And then there is the issue of # of teeth. Scott is trying to explain the difference to me, let me explain it this way: You have 500 softballs you have to move from one side of the road, to the other. You are given a basket that will hold up to 50 balls. You can load 25, or 50, into the basket for each trip. Fifty makes for a sort of heavy basket, so when you carry fifty, you walk more slowly. OTOH, when you're carrying 25 per trip, you have to make twice as many trips. Which method (25 or 50) is faster? How much work have you done in each case?

And then there is the issue of "something else." At least one magazine that has reviewed blades has included a feed pressure column. It wasn't that scientific, but they made a contraption with weights that applied a known force to a board and pushed it through the saw, to observe how quickly the blade cut. Very similar blades (same tooth count and configuration), from different manufacturers, had pretty dramatically different feed rates under this test. Why? Why wouldn't all blades, with nearly identical configurations, cut at exactly the same rate? What very small difference accounts for dramatically different feed rates?

Scott may not remember, but I once PM'd him over at bt3central.com about some Dewalt Precision blades I had tried. I found the blades cut very, very quickly. Put another way, feeding at the same rate, I had to apply much less force to cut the same material than I'd have to push on (for example) a Forrest or Freud blade (again, same # of teeth, same hook angle, same kerf, yada yada). He had recently tried one of the blades, and did comment that the blades seem to feed easier than others. Scott, do you remember that exchange? It was from a few years ago, so I'll forgive you if you do not. But at the time, I wondered why this blade would feed so much easier than nearly identical blades from other vendors. My recollection is that you had no idea.

And BTW, before someone pops his head into this thread and insults the lightweight tools I use and implies I don't know what I'm talking about because I use 10" bandsaws and a "toy" 6" jointer, my observations are formed from over 35 years of owning a table saw. I purchased my first saw new, a cast iron contractor's saw from Sears, when I was approx. 15, using money from my paper route. I purchased my BT3k saw approx. 13 or 14 years ago, and I have extensive experience using a Unisaw as well. My current blade collection includes multiple blades each from Freud, Amana, Leitz, Dewalt, and I'm forgetting others. I probably have 15-20 blades on hand now, and have had at least a dozen others over the years.

[Phil Thien]

I used a 3hp General 350 and would resaw up to and over 8/4 pretty regularly Phil and depending on the species and grain run out I would get packed gullets on occasion. I fed by hand at a pace that made the best finished surface. You don't have to be feeding fast at all.

Again, the blade is spinning 50 times per second. With a 20 tooth blade, each and every second there are 1000 teeth (with 1000 gullets) hitting your stock. I just don't know how you'd be packing those gullets (or even KNOW you're packing gullets) feeding at a rate any less that that of a fingerless mad-man.

So how fast do you think you were feeding that stock?

[Prashun Patel]

I used to use a combo for ripping and cross cutting. I did it for convenience and it worked quite nicely for me on stock < 2". I tend to use all my blades too long, which (like Phil) I believe is the main reason for burn/hard-to-push cuts.

IMHO, a combo is a very nice blade to have as the sole blade if you a) aren't ripping a lot of thicker stock and b) like to mill grooves and dados all with a single blade (some combos have a tooth set appropriate for that).

Nowadays, I find myself ripping a lot of thicker material, and doing a decent amount of post processing with jointers or planes or planers. If that's the case, the cut quality isn't as critical, and a 24-30t ripping blade is a good choice (for me) for a single blade.

[scott spencer]

Hey Phil - I do remember the PM exchange about the DW Precision Trim series (now made in China unfortunately). There are several given factors that influence feed rate and overall feel of any blade....tooth width, number of teeth, hook angle, side clearance, side angles, top angles, tooth geometry, sharpness, etc. Those DW blades had very low resistance within their other parameters, but the fact remains that if the exact same geometry and configuration are used, fewer teeth will have lower resistance than more teeth. That doesn't mean that you can't rip efficiently without burning using a 40T, 50T or even 60T blade, but if everything else is the same, they will always offer more resistance than a 20T, 24T, or 30T example that uses identical parameters.

[Phil Thien]

Hey Phil - I do remember the PM exchange about the DW Precision Trim series (now made in China unfortunately). There are several given factors that influence feed rate and overall feel of any blade....tooth width, number of teeth, hook angle, side clearance, side angles, top angles, tooth geometry, sharpness, etc. Those DW blades had very low resistance within their other parameters, but the fact remains that if the exact same geometry and configuration are used, fewer teeth will have lower resistance than more teeth. That doesn't mean that you can't rip efficiently without burning using a 40T, 50T or even 60T blade, but if everything else is the same, they will always offer more resistance than a 20T, 24T, or 30T example that uses identical parameters.

How much? How much will I reduce resistance by switching from a 40-tooth blade to a blade that is otherwise identical, but has 20 teeth?

I wouldn't think it would be much. The only way resistance would be reduced (I think) would be due to having fewer teeth in the kerf that aren't cutting but are now burnishing the already cut wood.

Is there another source of resistance I'm overlooking?

[Robert Delhommer Sr]

Sounds like you blade needs a good cleaning and more than likely a good sharpening.:)

[Rod Sheridan]

LOL, I respectfully disagree.

I used to notice a big difference back in the day when I used steel (non-carbide-tipped) blades.

With carbide, not so much.

PLEASE ANYONE READING ROD'S POST: There may be a tendency for someone reading that to try pushing stock into a rip blade faster than they're accustomed to doing so, to see how it works. Don't.

Phil, staying within the 3 HP saw catagory with a 24 tooth rip blade and 8/4 stock, feed speed would range from 60 feet per minute in white pine with a 0.006" chip thickness to 40 feet per minute for white oak with a 0.004" chip thickness.

Having had that job where I sat around and calculated feed speeds for wood machining and sawing, I can guarantee that people feed far too slowly when ripping by hand.

What seems like fast ripping by hand is far slower than the blade is designed for............Regards, Rod.

[Bill Huber]

I have found that is a lot of difference in Combo blades.

I have a Premier Fusion by Freud and it does cross cut really well but it does not rip 4/4 or above that well, it is in the design. It is a High-ATB blade with very small gullets. The Gmaxx that I now use is an ATB and has very large gullets and will do 8/4 on hard maple with no problem.

Both of these are combo blades but there is sure a difference in the design. The Gmaxx has really large gullets and the Fusion has very small gullets.

So what I have learned from these blades is ripping like large gullets. When I got the Gmaxx I had also a new Fusion as a back up to the one I used all the time. I took an 8/4 hard maple board about 14" long and did a rip, about a quarter of the way though the cut it started really pull the saw down and almost stopped it. Now this is just a Jet contractor saw, not a big cabinet saw.

I then put the Gmaxx on and did the same cut on the same board, it went right though it with little if no problem, this blade cut just about as good as my 24 tooth Freud glue line rip blade.

[Dave Cullen]

<snip>
So the guy goes out and buys a new rip blade, rips his stock, and reports back that "boy, it really did the trick, easy to feed and no burning." And now he is a convert. So the next time the same sort of thread appears, he chimes in as part of the choir and the pattern continues.

Never do people say "try a new sharp blade, any blade that is new and factory sharp." I think if people did try a brand-new combination blade, they'd find it does a pretty good job, even ripping 1-1/2" stock.

But the comparisons always boil down to a used, dull combination blade to a new sharp rip blade. Apples to oranges.



An excellent point. This blade has cut everything from MDF and plywood to framing lumber. It's the only blade I have and it's never given me any grief. I've never cleaned the teeth (didn't think I had to), and the saw's fence could use an alignment check. I think I'll get a new combo and find a sharpening service for this one. If I still have ripping issues, I'll go the dedicated rip route.

Thanks everyone.

[scott spencer]

How much? How much will I reduce resistance by switching from a 40-tooth blade to a blade that is otherwise identical, but has 20 teeth?

I wouldn't think it would be much. The only way resistance would be reduced (I think) would be due to having fewer teeth in the kerf that aren't cutting but are now burnishing the already cut wood.

Is there another source of resistance I'm overlooking?

You got me there....I can tell you what percentage of teeth you gained, but I don't think it's a linear correlation, so the resulting difference in resistance isn't likely to be even close to that.

Metal against wood at high speed causes friction. More teeth equates to having more metal in the wood at any given time, "if all else is equal" (notice that I keep reiterating that point). There can still be many variables that are different between blades of similar design....as you stated, sharpness is a big one, but all the other parameters have a big impact too. For example, take two 40T general purpose thin kerf blades that are pretty similar...one may have a hook angle of 18°, while the other is 20°...one may have a kerf of 0.100", the other may only be 0.091"...those are both fairly minor differences, but on a percentage basis both differ in the range of 10%. It's also only a couple of all the parameters that contribute to resistance. What we're cutting is another factor....some blades are better in hardwoods, some are better in softer materials. Whatever parameters DW went with on those blades made them feel like they were noticeably easier to cut with....noticeable enough that we discussed it. Those same parameters applied to their 24T blade from that series would undoubtedly be easier to cut with than the 40T.....I just can't say by how much. A guy like Tom Walz could probably explain it much more scientifically than I am.

[tom gepfrich]

I have a Freud industrial Glue line rip and it rips amazingly. I do most of my crosscuts on my miter saw and leave the rip blade on the saw.

[Chris Fournier]

Again, the blade is spinning 50 times per second. With a 20 tooth blade, each and every second there are 1000 teeth (with 1000 gullets) hitting your stock. I just don't know how you'd be packing those gullets (or even KNOW you're packing gullets) feeding at a rate any less that that of a fingerless mad-man.

So how fast do you think you were feeding that stock?

Phil, your math is off for my machine and the rip blade which I alluded to had 24 teeth. I don't understand why you throw yourself at this thread like this, it doesn't make sense.

You have never been in my shop and observed me ripping lumber on my TS. I am neither fingerless nor mad and I know that I can pack gullets because they will spit swarf at me as the blade exits the rip cut at the back of the cut. It's not complicated, it happens and I am merely human.

Rod is absolutely correct about feed speeds.

I would agree with you that sharp should be compared to sharp, that should be a given. Comparing sharp to sharp a rip blade is better at ripping than a combo blade. If a fellow does a lot of ripping why not get the right blade for the job? It really is that simple.

[Phil Thien]

Phil, your math is off for my machine and the rip blade which I alluded to had 24 teeth. I don't understand why you throw yourself at this thread like this, it doesn't make sense.

Was my math off by enough to negate my point? No.

In terms of your "I don't understand why you throw yourself at this thread like this" comment, well, this is an area that interests me keenly, where I've spent some time considering the variables, we are at a discussion site after all, and I've seen a lot of misinformation disseminated.


You have never been in my shop and observed me ripping lumber on my TS. I am neither fingerless nor mad and I know that I can pack gullets because they will spit swarf at me as the blade exits the rip cut at the back of the cut. It's not complicated, it happens and I am merely human.

Sigh, when I said "packed" I meant filled to capacity. I have the back of the blade throw stuff at me sometimes, too, but that doesn't mean my gullets are completely packed.



Rod is absolutely correct about feed speeds.


My warning was that people shouldn't try to match the feed rate of an auto feeder using fingers they'd like to keep. And that is sound advice.


I would agree with you that sharp should be compared to sharp, that should be a given. Comparing sharp to sharp a rip blade is better at ripping than a combo blade. If a fellow does a lot of ripping why not get the right blade for the job? It really is that simple.

The OP has already come back and said the blade he was using is old, and dull. So my instinct was spot-on.

In terms of using the right blade for the job, well, that was the point of nearly the entire thread.

The point being, until your feed rate and/or stock thickness approach those that require the deep gullets, then you don't really NEED a rip blade.

Here is an interesting read (source: http://www.bcsaw.com/blog/2010/08/548/):

Whenever anyone is discussing or asking about the merits of different style saw blades the first detail always referred to is the teeth; the quantity first, and then usually the style. I can't remember anyone ever asking me about the gullet of a saw. And usually when I mention it most users of saws don't know what the gullet is. The gullet of a saw is like the bucket on a backhoe - it carries the load of chips and dust out of the cut. It is the opening in the saw plate in front of the tooth. Just like the bucket - size matters - backhoes are categorized by the bucket volume (maybe we should categorize saws by the gullet capacity instead of tooth count).

But seriously, why would the average wood worker even care about the gullet capacity? The truth is, he probably wouldn't, because in most cases the saw blade gullet will handle far more than one tooth bites off, at normal feed rates. However, in stacked panel sawing applications or on power feed rip saws, or in cutting excessively thick material, relative to the saw diameter, the capacity of the gullet can be critical to performance and quality of cut.

On the Panel (or Beam)Saw, the thickness of material being cut is higher than in any other secondary wood cutting application. In this application each tooth gullet is usually filled to capacity. If the load becomes too much for the gullet, spillage will occur. This isn't an issue in the backhoe comparison because the excess just rolls out and is picked up later. But, on your Panel Saw the spillage rolls out the side and gets caught between the blade and the material. The blade is just a few thousands of an inch from that panel. And to add to this the blade is running at upwards of 3500 RPM, creating friction. So this spillage becomes packed in and hot in micro seconds. It sticks to the blade and continues to build until the friction gets the blade so hot it warps and runs out, ruining the cut, and in some cases permanently damaging the blade.

The solution is to either slow the feed rate so the bite per tooth is less or buy blades with fewer teeth. Yes, fewer teeth. On blades designed with fewer teeth, the teeth are, of course, farther apart which means larger gullet capacity, therefore having the ability to carry a bigger load out of the cut.

...

Doug Reid, Owner, BC Saw & Tool Inc. Posts originally appearing in Wood Industry Magazine.




Pretty much exactly what I've been saying, from a professional that is one of your countrymen. I can't help you any more than that.

[Lee Reep]

On my saw at home, and the one at work, a rip blade definitely rips better (faster, more easily) than a combo. A rip blade is designed to move wood out of the gullets faster and more efficiently. For any given manufacturer, their rip blade will rip better than their combo blade. Otherwise, why offer one?

Also, you have to have a common baseline for comparison. To compare cutting performance of a rip blade from Manufacturer A to a combo blade from Manufacturer B is a case or comparing apples and oranges.

And of course I mean carbide. I've been using carbide blades for 40 years. My 1976 Craftsman radial arm saw came with non-carbide blades. I still have them since I think of them as collector's items! But I would not use them to cut anything.

[Chris Fournier]

I really don't need your help in my shop Phil, you really aren't trying to help after all and quite frankly I'm pretty capable, you haven't much to add really. I hope that you enjoy working in your shop as much as I do in mine, enjoy your efforts.