Riving Knife Choices and Use

A discussion of the use of riving knives on the table saw, and of sources of aftermarket riving knives. March 22, 2013

A buddy of mine has a Unisaw and a riving knife or splitter - you simply pull a knob and slip it in, and when you're done, pull the knob and pull it back out. It's a great little set up and I considered buying one back in the day, but it was $120 and that was a lot of money then. Now I'd like to have one and can't seem to find it anywhere. so I'm assuming they don't make them anymore. Do you use them, and if so, what kind? I really just want one to rip hardwood, mainly to keep the wood from closing up on the blade.

Forum Responses
(Cabinetmaking Forum)
From contributor D:
I highly recommend the Shark Guard. Lee makes them to fit any saw and there are other options too. He sends different heights of splitters that you can use with or without the guard. I bought two of the heavy duty versions so that I did not need to change out splitters between cutting thick and thin wood. There is also a short height splitter for use without the guard. Another really cool thing is the dust collection. Lee is awesome and if I remember correctly, he made his own CNC machines. Delta used to have one but I see no point in getting it over the Shark Guard.

From contributor M:
Maybe this or something similar? Biesemeyer 78-961 T-Square anti-kickback snap-in spreader for Delta Unisaw - right tilt table saw.

From contributor J:
I have the Biesemeyer snap in version for my Unisaw but that saw is dedicated to dadoes, so not much use! I'd like to put one on my bigger saw but just haven't gotten around to it yet. When I rip 8/4 or thicker stock I keep a handful of shims on the saw in case the wood starts closing on the blade.

From contributor B:
I used to have an aftermarket riving knife/anti-kickback pawl on a Unisaw and was very happy with it. It was the type that popped in and out as you describe. Now we have the SawStop that has both the riving knife (without anti-kick back pawls) and the full guard. It takes a few seconds to switch back and forth between the two and we do it all the time.

From contributor L:
Their use is mandatory in our shop. OSHA thinks so too. A second benefit is not allowing the work to ride up on top of the blade and kick back. We've got one on our slider and also on the SawStop. The one on the SS is well designed and easy to change out for dados. I had one on a Unisaw - sort of okay, but the anti-kickback pawls were useless.

From contributor A:
I've worked on a Unisaw that had the riving knife with the pawls, which I like. Used it for several years. I've also worked on a Powermatic 66 with no riving knife. We did have a dust snorkel, but that was actually more dangerous than the blade itself. I had a piece of offcut birch (3/4" square, 8' long) grab the back of the blade, get pinched between the blade and snorkel, and it launched forward. I was standing sideways as I pulled the board I had just cut, and the launched offcut went through the front of my shirt (it hit the front buttons of the shirt, entered through the overlap on the front, skinned my belly, and exited the left side of my shirt). That never would have happened if my piece-of-crap supervisor had bought a riving knife like I nagged him for 5 years over.

From contributor T:
My policy is that if the guard/splitter can't be used, the riving knife must be on the saw. Of course I broke my own rule, and this resulted in my first and only table saw accident. I had taken the riving knife off my saw temporarily. I had bumped it out of adjustment, and was too lazy to fix it. Then one day I was ripping a small sheet of 1/4" thick PVC. Sure enough it caught the back of the blade, and turned into a projectile which hit my leather belt at about 100 MPH. A couple of smaller pieces broke off and hit me in the chest, which resulted in a few minor cuts. Had I not been using a push stick, I probably would have had my hand pulled into the blade faster than I could have reacted. I thought for sure I was going to be headed to the ER. Thankfully I was not injured. I think I got lucky.

From contributor A:
My first tablesaw kick (of the two that I've had) was quarter inch as well (plywood). I also was not using the riving knife, which was unusual at the time. We can become dependent on them. I used a Powermatic 66 for 6 years with no riving knife (despite my protests and demands to actually buy one), and the only accident I ever had with it is the one above.

From contributor L:
The thinner and lighter the material, the more likely to kick back. Foam board is terrible. A friend was ripping 1/4" strips off 3/4" pine when one kicked. Lucky for him he was standing out of alignment. The 6' long rip traveled about 8' to the raised panel garage door and stuck through the 3/4" panel about 3'. We wondered how far it would have stuck through him had he been in a slightly different location!

From contributor B:
I too once had an arrow like projectile incident in the shop. It was on the shaper instead of the table saw and fortunately I was not in the line of fire.

While profiling a crown moulding with the face against the shaper fence, the bottom approximate 1/2" x 1/2" excess material broke free and shot across the room. It went through a sheet of 3/4" particleboard, the 1/2" sheetrock on the wall and then the fiberglass insulation. It was still traveling so fast it forced the 1/2" plywood exterior sheathing out about 1/2" and completely blew a 6" x 6" section of pine clapboard right off the outside of the building. Gave me a new perspective on what a woodworking machine is capable of doing.