Thread: Blades for Table Saw

I'm running these two blades on that saw atm with the original riving knife- CMT Ripping Blade - 250mm - 24 Tooth | Carbatec
CMT Industrial Rip and Crosscut Blade - 250mm - 60 Tooth | Carbatec

3.2 for the combo blade and 2.8 for the rip one. I'm pretty happy with them.

You got a fully kitted out 50" jobbie if I recall correctly, yes? Sliding table, mobile base and zero clearance insert and all that? Christmas came early, enjoy!

Edit- Both out of stock atm, expected in two weeks so maybe you can source one elsewhere if you're desperate to get cutting, and I fully understand that. I sure would be.

Most non thin kerf blades will be 3.2mm, i.e. 1/8"

The CMT or Freud blades from Carbatec or Timbecon are good quality but all the standard kerf blades look to be out of stock. What type of blade are you after?

Perhaps a local saw doctor could help. These guys
Wide Bay Saw Service - Saw Sharpening Service in Hervey Bay

I had the same issue when I purchased my Carbatec TS. Without really thinking about it I purchased a CMT thin kerf blade and used it for a few months before I realised. I now have a CMT Industrial low noise blade, 3.2mm kerf. Works well.

This one looks to be in stock.
CMT Industrial Low Noise and Chrome Coated Blade - 250mm - 40 Tooth | Carbatec

Originally Posted by Norm C

Something I noticed is the riving knife is quite thick. Blade kerf needed is .102 to .126 inches. That is 2.6 mm to 3.2 mm.

Where do you buy a blade that thick there days? I’ve been looking online and can’t find any yet.

In the meantime I need to find a thick blade. Most of the manufacturers now advertise their thinner kerfs. Not much good to me.

I seem to be able to get a 2.5 mm kerf. Being just .1 mm narrow may be OK.

My advice ? DO NOT ATTEMPT THIS, IF THE SAW BLADE IS EVEN 0.1 mm NARROWER THAN THE RIVING KNIFE IT IS NOT OK.

The riving knife is possibly the most important safety feature of your new saw.
Don't compromise purchase a blade of the required width to match the knife.

Switching the knife to a narrower version that suits a narrow kerf blade will mean that you need to refit the wider riving knife every time you switch back to a standard kerf [1/8" = 3.175 mm] blade.

BTW, narrow kerf blades typically cut a 3/32" = 2.38125 mm kerf. (BTW: 3/32" = 0.09375" = 2.38125 mm)

Felders recommendation


Splitter / Riving Knife thickness => saw plate thickness + 0.2 mm & < saw kerf width.

My saw doesn't have a riving knife but my understanding has always been that the knife should be of a thickness between the thickness of the saw plate and the kerf. The idea is to prevent kick back, not to stop the work contacting the back of the saw blade, isn't it?

Originally Posted by aldav

My saw doesn't have a riving knife but my understanding has always been that the knife should be of a thickness between the thickness of the saw plate and the kerf. The idea is to prevent kick back, not to stop the work contacting the back of the saw blade, isn't it?

The work jamming or closing on the uplifting (back) of the saw is what causes kickbacks.

3.2mm is basically an industry standard for kerf under 400mm diameter, I just googled 250mm saw blade and the first 3 results that weren't specifically "thin kerf" were all 3 - 3.2mm, so if you can't find one I'm not sure where you're looking...

NEVER go narrower than the riving knife and NEVER use the saw without it unless you are cutting a groove/rebate/trench and the riving knife is higher than the blade.

Originally Posted by elanjacobs

NEVER go narrower than the riving knife and NEVER use the saw without it unless you are cutting a groove/rebate/trench and the riving knife is higher than the blade.

Quite a few of the Asia sourced Table Saws that I have looked at have riving knives that cannot be lowered enough so that the top of the blade is just proud of the riving knife, which means that users remove the riving knife for cutting a groove/rebate/trench and often "forget" to put it back for ripping & wide cross cuts.

My Woodfast TS250 certainly was that way and required some "fettling" to both align the riving knife with the blade and to remove some material from the top of the slot on the riving knife. It certainly had plenty of scope to adjust fore & aft for blade clearance.

Originally Posted by riverbuilder

The work jamming or closing on the uplifting (back) of the saw is what causes kickbacks.

Yes, the riving knife is to prevent jamming, stock can't jam between the blade and the fence if the riving knife is, say, .2 mm thinner than the saw kerf. So should the riving knife be thinner than the saw kerf or not? Mobyturns is the only contributor who has posted something definitive and that recommendation is that the riving knife should be thinner than the saw blade kerf. ian also stated that 'the saw blade (presumably kerf') should not be narrower than the knife' - that's the same thing isn't it? Everybody else has just posted confusing fairy floss - if you've got a contribution to make spell it out. Anybody reading this thread would be walking away none the wiser.

Originally Posted by aldav

So should the riving knife be thinner than the saw kerf or not?

Categorically yes.

Wider than the saw body, narrower than the teeth. Standard saw blades generally have tooth overhang 0.5mm either side of the body (3.2 kerf, 2.2 saw body)

The riving knife should be slightly thinner than the actual cutting size of the blade, everyone calls it “kerf”, which isn’t technically correct but that doesn’t matter. Ideally it should be approximately the same thickness as the body of the saw blade, but these vary a bit between manufacturers. The theory of the riving knife stopping kickbacks by stopping jamming against the blade is erroneous. In a properly set up saw, the fence should extend only to the centre of the blade AND NO FURTHER, which allows the material on the fence side to move away slightly from the uplifting side (or back) of the blade, reducing the risk of it being picked up and thrown towards the operator. The other reason a lot of people experience kickbacks is because they have the blade height SET WAY TOO LOW. This creates a very acute angle of attack for the cutting edges of the tips and also dramatically increases the tooth contact area with the material, making the saw work harder and dramatically reducing the cutting life of the tips before needing resharpening. The riving knife is mainly beneficial when ripping solid timber along the grain, where the natural action of the cut material is to close together after being cut, the riving knife stops this happening to an extent to prevent the timber closing on the uplifting back part of the blade and throwing the material back at the operator. I have not had one kickback in over 40 years. The riving knife is an absolutely essential part of the saw, and using a saw without one, is asking for trouble.
I hope my information, which I’ve gained from 35 years of professional experience, and 15 years of weekend and school holiday experience before that, and having been instructed by a master joiner who was working for 30 years before I was born, is enough to provide someone reading this thread with some assistance.

Originally Posted by riverbuilder

The other reason a lot of people experience kickbacks is because they have the blade height SET WAY TOO LOW. This creates a very acute angle of attack for the cutting edges of the tips and also dramatically increases the tooth contact area with the material, making the saw work harder and dramatically reducing the cutting life of the tips before needing resharpening.

Yep, but try telling that to basically every American on youtube...

Setting the blade low does tend to give a better surface finish though, so it is sometimes the better way to go.

Setting the blade low does tend to give a better surface finish though, so it is sometimes the better way to go.[/QUOTE]

Agreed, thin materials, plywood and laminates generally. Stops breakout underneath.
I’m not going to comment on Americans , bunch of arrogant tools.

Originally Posted by riverbuilder

...and dramatically reducing the cutting life of the tips before needing resharpening.

I don't understand this. It's the same number of teeth removing the same amount of material. Why do they wear faster?