Riving knife height?

Messages
5,629
Location
Catalunya
Hi all.
As I am new to using a TS I have a another question:

What is the right height of the riving knife? I understand that the riving knife plays an important role in preventing kick back and safety, but if I need to make grooves on the TS I understand that it must be set up as in the sketch below or removed which is always dangerous or so I think.

Any advice will be appreciated.

Thanks in advance.

riving knife.jpg
 
Most riving knives have easily adjustable heights, so you can set them where it seems most appropriate for what you're doing. For non-through cuts, you obviously want the knife set below the blade height. For through cuts, it's safer to have it come up above the blade because it leaves less of the back of blade exposed to launch lumber from. Mine is usually set above the blade height but can be adjusted in a few seconds as needed.
 
For cuts that don't go all the way through the wood, I simply remove the riving knife. There is no way to set the riving knife lower thant the blade on my saw, and even if there were, the anti-kickback pawls would be useless. The kerf is unlikely to pinch the blade, as it is supported by the top of the cut. I avoid standing directly behind the workpiece, even when I am using the anti kickback pawls, so that any piece of wood flying back off the saw will miss me and kill anyone standing behind me watching.
 
My MiniMax machine specified that the riving knife should be slightly above the blade, but they also said that Europeans do not allow a saw to be used for non-through cuts (which is why dado blades are frowned upon in Europe). Therefore on my smaller (10 inch) blades I could not lower it below blade height.

With a Dremel grinding wheel I elongated the slot where the riving knife is mounted (5-10 minute job). At first I thought I needed a curved path to move it farther away from the blade but that was wrong - on my machine the adjustment for the horizontal distance away is separate from the height. Therefore the slot was just elongated vertically about 1/2 inch (13 mm) on my machine. I adjust the height to be just short of the blade height - just enough so that it does not lift the work piece if I am cutting a groove. My manual specifies 3 mm separation from the blade, which I am able to maintain. Be sure the knife is tight - if it is bumped into the blade, the blade will need substantial resharpening. (Don't ask me how I know).

I only adjust the knife when I change blades, and I never remove the knife in routine use.
 
Mine is about a 1/16" (1.6 MM) above the blade that's in the saw right now, and it can't be adjusted. This blade has been sharpened a couple of times, that may be why it's shorter. I'd just pull the knife off if making a non through cut.
 
The instructions for my G0690 table saw say the correct adjustment for the riving knife is 1/8" below the top of the blade. That's one reason I chose this saw a couple of years ago. Many of the other saws had the riving knife above the blade, which puts it in the way of making a narrow groove (dado) without removing it.
 
Top