# 60 tooth circular Diablo blade? Or will 40 tooth be enough for my work?



## brandall (Jan 30, 2013)

I'm working on a headboard. It's a pretty simple one, which is good since I'm new to making furniture. All the cuts I've made in the past have been for home improvement, such as trim, flooring, etc.

So I have a measly 12-amp Skil circular saw that I'm using, in addition to my father-in-law's Ryobi 7-1/4" compound miter saw. And I'm cutting into whitewood pieces ranging from 1x6 to 2x4. A couple of the pieces, it didn't matter if there was splintering as one end will be hidden in the final headboard.

However, I'm getting some splintering from both saws. Not on the top of the wood, but on the end of the wood when the saw exits the far side. I have done some tests on scrap pieces and tried different speeds of cutting, clamping/holding the end that will fall, etc. No luck.

Both of my saws have steel blades in them. The circular has a 20 tooth blade that came with the saw(yeah, stock, so probably not a very good one). The miter has a 24 tooth stock blade.

So I researched saw blades, and determined that part of my problem is that these blades really aren't made for furniture-type work, and for the money, the Diablo blades were pretty good bang for the buck. My father-in-law, who is a contractor, says they are a great brand and he even has some. And I have yet to see a truly negative review of them(I'm open to suggestions if anyone has them, but it has to be in the same price range as money is tight).

So my question is whether or not it's worth the extra five bucks at Home Depot to get the 60 tooth blade, or if the 40 tooth blade will be perfectly fine for what I'm doing? I'm not doing any rip cuts in this particular project, though I will at some point I'm sure. 

Is 60 overkill for what I need? The Diablo website suggest it for finer work and miter work, but with the wood I'm using, I don't know if it will make a difference or not. And of course, I'm completely aware that it could be a technique issue as well. But I figured you gotta learn somewhere, right?

Any help or advice is definitely appreciated! Thanks!

Brent


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## Duncancruiser (Dec 6, 2011)

I have 2 60 tooth Diablo blades. 1 in my table saw and 1 in my compound mitre saw. Very nice to use. I've never tried the 40 tooth. So not too sure. I've read lots about using a higher tooth count for smoother cuts.


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## Chris Curl (Jan 1, 2013)

From one perspective, 40 teeth on a 7" blade is like 57 teeth on a 10" blade. the teeth are 0.55" apart.

But the difference in blade size makes is significant when the RPM of the saw is factored in.

A bigger blade at the same RPM will result in more cuts per second than a smaller saw.

A 10" blade with 57 teeth going at 7000 RPM (typical table saw speed) will result in 399,000 teeth (cuts) per second.
A 7" blade with 40 teeth at the same speed gives 280,000 teeth (cuts) per second.

So even though the teeth are spaced the same distance apart between the 2 blades, the velocity at the edge of the larger blade is faster than that of a smaller blade. So you get more cuts per second and a smoother cut.

So if you want table saw smoothness out of a circular saw you need to use the most teeth you can.

Make sense?

All that said, it seems to me that 40 teeth on a 7" circular saw is plenty for what you are doing.

The tearout at the end is because the wood where the saw exits is not supported. So try to clamp another piece the same thickness to the end where the saw exits. Then you will get less tearout.

You will also find you get less tearout is you move the saw slower at the end while it is coming out of the wood.


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## brandall (Jan 30, 2013)

Chris Curl said:


> I think that 40 teeth on a 7-7 1/2" circular saw is plenty. If you were using a 10" saw, I'd say go with the 60.


Thanks. And that is why I was curious. I know that technically, more teeth equals better cuts, but is there a point where the return on investment plateaus and on such a small blade, will I even notice the difference?

Brent


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## brandall (Jan 30, 2013)

Duncancruiser said:


> I have 2 60 tooth Diablo blades. 1 in my table saw and 1 in my compound mitre saw. Very nice to use. I've never tried the 40 tooth. So not too sure. I've read lots about using a higher tooth count for smoother cuts.


That's where I'm at. I 'read' that as well, in many places. Which is why I have been considering the 60 tooth. 

But I've also heard about there being slightly more drag because of the extra teeth, causing friction and buildup. 

Considering I'm coming from a thicker, 20 tooth steel blade and going to a higher tooth count carbine tip thin kerf blade, I'm assuming the results will be significant regardless of which one I choose.

I also build computers, and I know that having a power supply with TOO much power can actually hinder performance because they are rated for a certain load. So I was curious if that was the same situation here, where I might regret the 60 tooth blade.

Brent


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## Duncancruiser (Dec 6, 2011)

I haven't noticed any difference with my saws. They both work great. No power loss.


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## brandall (Jan 30, 2013)

Chris Curl said:


> From one perspective, 40 teeth on a 7" blade is like 57 teeth on a 10" blade. the teeth are 0.55" apart.
> 
> But the difference in blade size makes is significant when the RPM of the saw is factored in.
> 
> ...


Thanks Chris. I just saw your additions to your post, and it makes a lot of sense when you do the math. 

I would like to get both, but money is tight for a couple of weeks and so I want to get the one that will work the best for the job I'm doing. So I appreciate the sound advice!

Brent


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## Chris Curl (Jan 1, 2013)

brandall said:


> Thanks Chris. I just saw your additions to your post, and it makes a lot of sense when you do the math.
> 
> I would like to get both, but money is tight for a couple of weeks and so I want to get the one that will work the best for the job I'm doing. So I appreciate the sound advice!
> 
> Brent


yeah, sorry, i have edited it a few times ...


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## brandall (Jan 30, 2013)

Duncancruiser said:


> I haven't noticed any difference with my saws. They both work great. No power loss.


So you have used both the 40 and 60 tooth Diablo blades? I did see one reviewer on the Home Depot site who said the same thing, no large difference. 

Brent


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## Chris Curl (Jan 1, 2013)

I added this even later:

The tearout at the end is because the wood where the saw exits is not supported. So try to clamp another piece the same thickness to the end where the saw exits. Then you will get less tearout.

You will also find you get less tearout is you move the saw slower at the end while it is coming out of the wood.


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## brandall (Jan 30, 2013)

Chris Curl said:


> yeah, sorry, i have edited it a few times ...


Haha, no problem. It's much appreciated.

I'm glad I found this place as I'm sure I'll have loads more questions as I discover new cool things to buy and build. As a newbie, I figure asking questions is the best thing I can do to avoid wasting money!

Brent


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## brandall (Jan 30, 2013)

Chris Curl said:


> I added this even later:
> 
> The tearout at the end is because the wood where the saw exits is not supported. So try to clamp another piece the same thickness to the end where the saw exits. Then you will get less tearout.
> 
> You will also find you get less tearout is you move the saw slower at the end while it is coming out of the wood.


You mean to clamp another piece right next to it? Or on top/below it?

I'll try slowing down at the end more as well on some scrap wood tonight. I'm pretty sure that my problem is a combination of blade and technique issues.

Brent


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## brandall (Jan 30, 2013)

Does anyone here recommend taping the end that is tearing out(I guess I called it splintering, though I don't completely know the difference?)? Or using a utility knife to score the part that is tearing out?

I've read about people doing these things, but not sure if they are worth the trouble.

Brent


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## RogerInColorado (Jan 16, 2013)

I think what Chris means about "clamping a board" is that you need to create a zero clearance "insert" to reduce tear out at the blade exit from the stock. On my miter saw I can screw a piece of plywood to the fence. Look at the fence on your saw and see if there are two or more small holes in the fence on each side of where the blade passes through the fence. If so, cut a piece of (1/2 inch or so) plywood that is at least as long as the total length of the fence and the same height as the fence. screw the plywood to the fence from the back of the fence. Cut through the plywood to create a zero clearance insert. Now all of the cuts from this set- up will be supported at the exit point of the blade and will dramatically reduce tear-out. If you have to rotate your saw to cut angles, you will have to create a new insert each time. That part is a pain, but it works.

If you can't screw it to the fence, you can probably attach a fence with some double sided tape.

My observation is that given a choice, whitewood would rather splinter than cut.


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## Chris Curl (Jan 1, 2013)

see the pic .. maybe that will help ...


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## Duncancruiser (Dec 6, 2011)

I haven't used the 40 tooth Diablo. But I have used other 40 tooth blades. And no speed difference. I might also add that I'm using 10" blades.


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## Chris Curl (Jan 1, 2013)

RogerInColorado said:


> On my miter saw I can screw a piece of plywood to the fence. Look at the fence on your saw and see if there are two or more small holes in the fence on each side of where the blade passes through the fence.


ah-hah! so that is what those holes are for!

thanks!


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## brandall (Jan 30, 2013)

Great! Thanks for the good info. The graphic helps for sure, and is definitely doable. And I'll look for the additional holes on the miter. It's just a simple Ryobi compound miter, so I don't know if those have it or not. But I'll check. 

I'm learning a lot, and FAST. I've been living this stuff for the past few weeks, trying to pick up technique and advice along the way. I started the whole thing by building my own sawhorses, which turned out great. But not exactly the most precise or "clean" project in the world. So this headboard is my first real experiment. My wife has wanted one forever, so I figured, why not try and make her one?

Thanks again!

Brent


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## knotscott (Nov 8, 2007)

brandall said:


> ...So I was curious if that was the same situation here, where I might regret the 60 tooth blade.
> 
> Brent


Could be. More teeth _tends_ to equal a cleaner cut if all else is equal, but it also means more resistance, more heat, more bogging, which can lead to burning in some materials and thicker materials. 40T sounds about right for cutting common lumber sizes smoothly. 60T would be nice for plywood and extra smooth crosscuts. I'd start with the 40T and see how it goes.


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## knotscott (Nov 8, 2007)

Duncancruiser said:


> I haven't used the 40 tooth Diablo. But I have used other 40 tooth blades. And no speed difference. I might also add that I'm using 10" blades.


Adding 50% more teeth should increase the resistance (by a fair amount)....it's just a matter of physics. Whether or not you'll notice the difference or hear the saw motor slow down depends on several other factors....like the saw's power, material thickness, material density, feed rate, moisture content, etc.


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## ryan50hrl (Jun 30, 2012)

[quote="Chris]

A 10" blade with 57 teeth going at 7000 RPM (typical table saw speed) will result in 399,000 teeth (cuts) per second.
[/quote]

FYI it's cuts per minute, it would take 420000 rpm to get those cuts per second......

And most table saws are 3450 rpm


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## Chris Curl (Jan 1, 2013)

ryan50hrl said:


> FYI it's cuts per minute, it would take 420000 rpm to get those cuts per second......
> 
> And most table saws are 3450 rpm


each tooth on the blade makes one cut, yes?

so if there are 60 teeth on the blade, the the number of cuts in one revolution of the blad is 60, or 60 cuts per revolution. If the blade is spinning at 3450 revolutions per minute, then the number of cuts per minute is: 3450 * 60 = 207,000 cuts per minute.

i don't know why, but i though i saw that my table saw spins at 7000 RPM. but that was a while ago that i am remembering, and i could be remembering it completely wrong.

EDIT: yes, i meant cuts per minute, not cuts per second.


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## Duane Bledsoe (Oct 18, 2012)

This will muddy the water for you just a bit because I have no explanation at all for it, or rather a weak one that is. Anyway...

I have this saw...

http://www.sears.com/craftsman-1087...p-00910870000P?prdNo=2&blockNo=2&blockType=G2

...and I put a 24 tooth Freud Diablo 7 1/4 inch blade on it. It cuts superbly on cross cuts, leaving smooth ends with no tearout as the blade exits the wood. I've cut 2x4's and 2x6's as well as 1x6's, and even MDF with it. I've even cut 4x4's with it. I get very smooth cuts, never any splintering, even with a 24 tooth blade. It rips well, and seems to crosscut extremely well also. I wouldn't have thought this when I got this blade. The saw has always been good for power but just average on cut quality, same as any other circ saw. Adding this Diablo blade has transformed it, or so it seems. This saw is mostly used on construction jobs where having a smooth crosscut doesn't even count but it's been good enough I don't hesitate to use it in my wood projects now either. 

My only explanation has to do with the saw and blade combo, since it has such a strong motor (14 amps) and the blade is a thinner kerf than the factory blade was. Maybe having ample power to push the blade through wood, and then having a thinner blade where that much power wouldn't even be needed anyway is all it took. I'm saying maybe I got lucky and found a good combination of saw and blade together. Whatever the reason, it cuts excellently. I paid $11 for the blade. I know I can get cheaper blades, and I also don't know if there are any that cost a lot more or not, but I won't be looking because when I need another one, I'll be getting the same one again. It was worth every penny.


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## brandall (Jan 30, 2013)

Before I get into details, let me just say that before tonight, I was unsure, as many newbies probably are. I hadn't fully had "fun" yet working with wood. But figuring it all out and finding my own solutions along with using suggestions from others, there was a good feeling of fun accomplishment tonight(even though the end goal was nothing more than a simple straight and non-splintered cut).

So I went ahead and bought the 40 tooth model. Brought it home and put it on my circular saw(it looks MUCH more formidable now, ha!). Did some test cuts and the difference is night and day. The edges are much cleaner, and the end surface is definitely smoother with less saw marks. I got it for $15 and it was worth every penny. 

And what is probably even better is that this blade cuts the wood on it's own, where my other blade it felt like I was pushing the saw through the wood. The slogan I heard for the Diablo blades was "like a knife through butter", and that seems pretty accurate. 

Now, the cut isn't completely perfect, so I got some scrap strips of MDF and used them as suggested earlier in the image, as kind of a endstop for the wood. Problem solved. 

A few days ago, I built a straight guide that I fit to my circular saw so I can make straight cuts, and it is working great(you can see it on the left in the image below). It's a similar model to what you see others use around the web.

The only other issue I'm having is when the wood falls off and I am not at the right position to catch it. This actually creates a significant amount of tearing out, as I discovered. So tonight I took some more wood that I had sitting around, and made a sturdy little 20 inch long table to place under the pieces. Kind of a "feed" table, but without wheels. Another problem solved. 

And in the end, I was able to make what I considered a pretty good cut:











I'm sure there is something else I could do, but I'm feeling like I got quite a bit out of the experience. It's like a small victory, but one that will affect much of the work I do in the future.

Sorry for the length of this post, but I just wanted to share my "process", even though I'm sure it's very small potatoes to most of you here. 

Thanks!

Brent


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## ryan50hrl (Jun 30, 2012)

Good work!


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## rayking49 (Nov 6, 2011)

That's great man. And when you finish that headboard you'll be hooked. Welcome to the addiction. Lol


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## Duane Bledsoe (Oct 18, 2012)

Whenever I cut wood with a circular saw I try to have the save piece and the cut off piece fully supported. Especially for heavy boards like 2x12's. I made my saw horses so the top rail has an overhang all the way around (it's just a 2x6 laying flat). This way I can clamp down my board for cutting. I can keep two hands on the saw that way for steady control and the board doesn't move. If I'm cutting a long board I just move my horses end to end of each other and use two or three clamps to hold it down. The top rail of my horses serves as sacrificial so I don't worry too much if I hit it with the blade on the cut since I'd rather have the board supported. I just set the depth of the blade to just knick it though so it doesn't get eat up too much, plus I don't want to hit a screw holding the top rail on. When the board gets eat up too much, I'll change it out. One $5 board will replace both tops on the horses.


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## brandall (Jan 30, 2013)

Thanks guys. I can see where it can get addicting, indeed. Now, I'm obviously very early in the game, but I think the key, at least for me, is small victories. That's progress I can point to and grow with. 

I don't yet know how the headboard will turn out. But I'm pretty sure that once it is done, I'll be wanting to move on to new projects. Heck, my wife already wants other matching furniture, lol!

I've spent a lot of time reading, getting free trials for magazines like Family Handyman, etc., and watching videos. A lot of what I see, I can't yet do because of a lack of tools. But I feel I'm already getting a good head start.

So we'll see how it goes! I'll be sure to share the headboard pics when it's done, and will probably need more tips along the way! Thanks!

Brent


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## brandall (Jan 30, 2013)

Duane Bledsoe said:


> Whenever I cut wood with a circular saw I try to have the save piece and the cut off piece fully supported. Especially for heavy boards like 2x12's. I made my saw horses so the top rail has an overhang all the way around (it's just a 2x6 laying flat). This way I can clamp down my board for cutting. I can keep two hands on the saw that way for steady control and the board doesn't move. If I'm cutting a long board I just move my horses end to end of each other and use two or three clamps to hold it down. The top rail of my horses serves as sacrificial so I don't worry too much if I hit it with the blade on the cut since I'd rather have the board supported. I just set the depth of the blade to just knick it though so it doesn't get eat up too much, plus I don't want to hit a screw holding the top rail on. When the board gets eat up too much, I'll change it out. One $5 board will replace both tops on the horses.


Thanks. Yeah, that was what I discovered. I was already clamping down the save piece. I just line it up with the edge of my table(which is just two sawhorses I built myself with a 2 foot by 4 foot 3/4" board on top). So that was clamped down. Now I have the extra table that can hold the cut off piece. I just place that little table in the middle of what will be cut off so it will be balanced, and I clamp the cut off piece to the table as well. It seems to have worked very well, and it's something that I would have never thought about until I actually started cutting pieces where the cut needed to be clean.

Brent


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