Circular Saw Blade question

[graham-xrf]

Does the riving knife plate that mounts close behind a circular saw blade have to be at least as thick as the saw blade cut width?

I have one of those reconfigurable aluminium saw table units with fence that has adapter mounts to fit most portable circular saws and routers underneath. I use it in "table saw" mode, presently using a claimed "thin" type saw blade. The teeth measure 2.12 mm wide (3/32") and the riving knife seems to be made of 2mm plated steel.

If I were to try a thicker stiffer blade, having kerf 2.8mm or more, do I have to install a thicker riving knife?
I have heard that a circular saw can suddenly "launch" the work across the room, or up out of the saw.

 

[mickri]

Stumpy Nubs has some good videos on riving knives for table saws. https://www.youtube.com/c/StumpyNubs

The quick answer is the knife needs to be the same thickness or slightly thicker to prevent kick backs.

 

[Martin W]

Ideally it should be nearly thick as the blade kerf, or a hair smaller. My riving knifeis always thinner than the blade Riving knives work excellent for solid woods where there can be a lot of tension in the wood. Most will have anti kickback fingers to prevent kick backs. Spreaders will be thicker than the blade
You want the riving knife as close to the blade as possible
I have seen more kick back accidents from a piece binding against the fence or coming away from the fence, while making a cross cut As well as the piece rising up off the table.
Sharp saw blades are the easiest thing to prevent all of these problems.

We use riving knives in our shop, as well as a blade guard. Been in the trade for 40 plus years, still have all my digits. Not to say I haven’t had a kick back into the gut .

 

[graham-xrf]

Stumpy Nubs has some good videos on riving knives for table saws. https://www.youtube.com/c/StumpyNubs

The quick answer is the knife needs to be the same thickness or slightly thicker to prevent kick backs.

Thanks for the Stumpy Nubs link. He is awesome!
Thanks also @Martin W . Yours is experience I need to tap into!

There may be subtleties in terminology here. It seems riving knife is what the gadget is called when the cut does not come all the way through the wood, and splitter is what it is called when the wood is cut right through. That piece may be incorporated into a plastic guard. Single purpose table saws have them. My "table saw" is using a portable hand saw converted into table saw duty, so the plate that keeps the wood apart is what it comes with.

I have discovered that the "one size fits all" splitter (also called "spreader") always has to be thicker than the blade body, but can be thinner than cutting teeth, so able to manage a over range of cutting tooth widths. Wood can bind up on the saw blade body, but not on the wider teeth. Stumpy Nubs shows a spreader that is OK for a range of tooth widths, basically covering all the common blade blade kerfs from it's own thickness up to 3.5mm. (3/32" to 9/64").