Riving Knife

[BOB OLINGER]

Sorry for my ignorance; I've been woodworking as a weekend hobbyist for 30 yrs or so and haven't been exposed to a "riving knife" or "splitter." Could you guys clue me in? All this talk about the new contractors and cabinet saws, makes me drewl (sp?) - I still have a Delta 9" contractors version my Dad purchased for me in the mid "70's - it was king back then, a real workhorse, but looks like its been passed up in technology. Thanks in advance; great website!!!!!!

[Eric Haycraft]

Sorry for my ignorance; I've been woodworking as a weekend hobbyist for 30 yrs or so and haven't been exposed to a "riving knife" or "splitter." Could you guys clue me in? All this talk about the new contractors and cabinet saws, makes me drewl (sp?) - I still have a Delta 9" contractors version my Dad purchased for me in the mid "70's - it was king back then, a real workhorse, but looks like its been passed up in technology. Thanks in advance; great website!!!!!!

Both a splitter and a riving knife serve the purpose of keeping the wood from binding against the back of the saw blade. This is done in two ways. First, the splitter/riving knife is nearly as wide as the blade, so if the board you are ripping want's to contract against the blade after being cut (say there is some tension in the wood) it will contract against the splitter/riving knife and not against the blade. Additionally, the splitter/riving knife keeps the wood aligned as it is pushed through the saw which also helps prevent binding and kickback.

So, they both serve the same purpose, but a riving knife is different in many ways. A splitter is always at a fixed height and needs to be removed for non-thru cuts. A riving knive moves up and down with the blade. In fact, it is usually less than 1/4 of an inch away from the blade at all times. There are low profile riving knifes available that do not stick above the blade at all meaning that they can be left in place for all non-dado cuts. The riving knife is almost universally regarded as being safer for two main reasons.. they can be left in all the time with the exception of a dado blade, and since they are so close to the blade, there is very little gap between the splitter and the rear teeth of the blade. Since this gap is very small and always small regardless of the height of the blade, it is much more difficult for the wood to pinch the rear of the blade or get misaligned causing kickbacks.

Eric