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Table Saw blades and cuts

4K views 22 replies 6 participants last post by  TomCT2 
#1 · (Edited)
I am building a crosscut sled this weekend for my Dewalt 7491RS table saw and currently have the dewalt blade on it. I just put a 50-60tooth diablo on my miter saw that I dont use that often. Everything I have read says a 50 tooth Diablo combination blade will do crosscuts and rips. I really cant afford to buy several blades so what do you guys think about the combination blade. I am just building outdoor stuff like planters, chairs, etc. I may dabble in some small patio tables and need to joint and glue on the table saw.

Another concern I have is Dewalt says dont use anything larger than 2.2mm thick blades because they are thicker than the riving knife. Diablo list their blades at 2.4mm thick.
 
#2 ·
I never went Metric so .......

The Diablo 50 tooth blade measures 0.098" thick:
https://www.amazon.com/Diablo-D1050X-Combination-Saw-Blade/dp/B00008WQ2Z


How thick is your riving knife in inches? It would be highly unlikely that the thin kerf Diablo blades which are so common these days will not work on any newer table saw, no matter the brand or model.


I used a 40 tooth Diablo blade for several years, it never really got noticably dull, but I just swapped it out last year for the 50 tooth. There is some slow down in the feed rate when ripping, but otherwise give good performance crosscutting various materials and plywood with thin veneers. You may find that you will need a dedicated 24 tooth rip blade eventually IF you cut 2" or thicker hardwood. :|
 
#4 ·
the diablo 50 tooth blade measures 0.098" thick:
https://www.amazon.com/diablo-d1050x-combination-saw-blade/dp/b00008wq2z


how thick is your riving knife in inches? It would be highly unlikely that the thin kerf diablo blades which are so common these days will not work on any newer table saw, no matter the brand or model.


I used a 40 tooth diablo blade for several years, it never really got noticably dull, but i just swapped it out last year for the 50 tooth. There is some slow down in the feed rate when ripping, but otherwise give good performance crosscutting various materials and plywood with thin veneers. You may find that you will need a dedicated 24 tooth rip blade eventually if you cut 2" or thicker hardwood. <img src="http://www.woodworkingtalk.com/images/woodworkingtalk_2016/smilies/tango_face_plain.png" border="0" alt="" title="serious" class="inlineimg" />
0.086
 
#3 ·
the manual says:
NOTE: Different types of blades make different kerfs (width of cuts). Therefore, it is
necessary to check adjustment of rip scale when changing blades. Replacement blade
MUST not exceed the thickness stated on the riving knife. The riving knife provided with
the saw is 2.2 mm thick.


so I suggest you check the information on the riving knife.
my experience has been a kerf narrower than the riving knife thickness makes for severe problems.
 
#6 ·
MUST not exceed the thickness stated on the riving knife - stated on the knife, not the thickness of the riving knife.

here's from my Delta - as you can see they explicitly say the kerf must be wider - the read of
"MUST not exceed the thickness stated on the riving knife"
is different from
"MUST not exceed the thickness of the riving knife"


using thin blades, I had to have my riving knife _ground thinner_ because rip cuts would jam - very un-nice.
Machine tool Machine Steel Metal Lathe
 
#7 ·
Blades have multiple important dimensions:

* Kerf: The width of the cut.
+ A typical thin kerf blade is 3/32 inch (0.09375 inch = 2.38 mm)
+ A typical full kerf blade is 1/8 inch (0.125 inch = 3.18 mm)

* Body thickness: The thickness of the flat disk part of the blade, excluding the blade tips.
+ See my measurements below for various blade body thicknesses.

* Diameter: Normally 10 inch for a typical table saw.
* Arbor hole size: Normally 5/8 inch for a typical table saw.

The kerf MUST be wider than the riving knife thickness. Otherwise, one or both sides of the cut will bump into the riving knife and stop or deflect the wood, leading to a dangerous situation.

The DeWalt DWE 7491RS user manual says:

'The riving knife provided with this saw is marked as follows:
0.087" (2.2 mm) THICK RIVING KNIFE. ONLY USE FOR 10" (254 MM) [diameter] BLADE WITH 0.094" (2.4 MM) MIN. KERF WIDTH AND 0.067" (1.75 MM) MAX BODY THICKNESS.'


The DeWalt requirement for a 0.067" (1.75 mm) maximum body thickness is thinner than any of the blades that I just measured with calipers:

Thin Kerf Body Thickness
Diablo D1060X: 1.87 mm = 0.074 inch
Makita A93681: 1.82 mm = 0.072 inch
Forrest Woodworker II #6: 1.90 mm = 0.075 inch
Bosch CBT1040A: 1.87 mm = 0.074 inch
Craftsman (too worn to read): 1.86 mm = 0.073 inch

Full Kerf Body Thickness
Freud Fusion P410: 2.52 mm = 0.099 inch
Forrest Woodworker II: 2.34 mm = 0.092 inch

Other Kerf Body Thickness
SawStop (came with PCS175): 2.00 mm = 0.079 inch
(and carbide tips measured an uncommon 3.00 mm)

In case it matters, my old Bosch REAXX jobsite saw manual says, "You must select a blade with a kerf width of .094” or more and a plate (body) thickness .090” or less [...]"
 
#8 · (Edited)
I am building a crosscut sled this weekend for my Dewalt 7491RS table saw and currently have the dewalt blade on it. I just put a 50-60tooth diablo on my miter saw that I dont use that often. Everything I have read says a 50 tooth Diablo combination blade will do crosscuts and rips. I really cant afford to buy several blades so what do you guys think about the combination blade.
Here is another thought regardless of your riving knife thickness. I have the same saw as you and bought a 60-tooth blade for crosscuts in the sled I built. Works fantastic. When I tried to do some ripping with that blade, the high tooth count ran very slow on the first cut, then I tripped the circuit breaker when I tried starting the saw for the second cut. Too much resistance. I removed the 60-tooth blade & reinstalled the 32-tooth and had no more breaker trips. So while you think you may be saving a bit of coin, you may create anoher problem if your saw can't push that 50-tooth blade well.
EDIT TO ADD: BTW, the ripping I attempted was in dried 1x6 (1" thick) treated deck boards.
 
#9 · (Edited)
This is not clear to me ...

You stated this:
(what?) ... MUST not exceed the thickness stated on the riving knife - stated on the knife, not the thickness of the riving knife.

here's from my Delta - as you can see they explicitly say the kerf must be wider - the read of ........(What does this mean?)
(what?) ....."MUST not exceed the thickness stated on the riving knife"
is different from
(what?) ...... "MUST not exceed the thickness of the riving knife"



Regardless of all the measurements and data the conclusion is:
A thin kerf Diablo 0.094" will not work on this saw. RIGHT? It needs to be ground down. RIGHT?


If that is the case, what the heck were they thinkin'? Thin kerf blades are more common than house flies in the city dump. DUH.


After some additional thought, you really wouldn't use the riving knife with your crosscut sled anyway ....
 
#11 ·
You stated this:
(what?) ... MUST not exceed the thickness stated on the riving knife - stated on the knife, not the thickness of the riving knife.

here's from my Delta - as you can see they explicitly say the kerf must be wider - the read of ........(What does this mean?)
(what?) ....."MUST not exceed the thickness stated on the riving knife"
is different from
(what?) ...... "MUST not exceed the thickness of the riving knife"



Regardless of all the measurements and data the conclusion is:
A thin kerf Diablo 0.094" will not work on this saw. RIGHT? It needs to be ground down. RIGHT?


If that is the case, what the heck were they thinkin'? Thin kerf blades are more common than house flies in the city dump. DUH.


After some additional thought, you really wouldn't use the riving knife with your crosscut sled anyway ....
while no knife on the crosscut sled I would like to rip with the same blade too.
 
#10 · (Edited)
P.S. I was curious about that measured 3.0 mm kerf blade and whether it might be standard in other parts of the world that use metric.

I found some 3 mm kerf blades online, but also found this well-written article about thin kerf blades and thick kerf blades, related to riving knife thickness and positioning:

https://www.trentdavis.net/wp/2019/10/23/thin-kerf-blades-and-riving-knives/


P.P.S. The article also confirms that the kerf on that SawStop blade is 0.118 inch (= 3 mm), which matches what I measured across a few teeth.
 
#14 ·
the D1060X kerf is given as 0.098"=2.4892 mm

that should work just fine with your 2.2 mm riving knife.


broad brush.... one can rip and cross cut with the same blade, up to a point.
thick stock and/or hard stock and/or 'sticky' stock will cause problems for long cuts one after another after another.
rip a 16" chunk, not a problem. rip 20 pcs 96 inches long.... likely not going to go well.


eventually you'll want to get a rip blade. in 10", 20-30 tooth count, flat top grind (FTG) is a good choice for cutting ease, especially in thick (1"+) stock
 
#23 ·
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