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I recently bought an older table saw that doesn't have a riving knife/ splitter, so I've been looking at options online, the mj splitter is one I've been thinking about, what about this though, do you think i could screw this on the underside of my ZCI? It seems like it would work... or am I missing something?

 

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ITs meant to mount on the trunnion - the thing that holds the saw blade (and maybe also the motor) - not the table top.
 
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Nice idea, but I would NOT do it. It would be a serious safety concern.

I had a Bosch jobsite table saw that used that part. @kiwi_outdoors is correct. That Bosch riving knife attaches to the trunnions and is designed to move up and down with the blade. It has two pins (not shown) that go into those matching holes on the riving knife, so it has only three height positions, and the riving knife itself curves around the blade above and below the table. That works on Bosch table saws, because the arc of the riving knife stays relative to the blade. The top of the riving knife is designed to fit Bosch's blade guard.

If you attach it to the underside of the zero clearance insert (ZCI), then a fully raised 10 inch blade will contact the riving knife. The riving knife won't go high enough, due to the thickness of the ZCI. If you lower the height of the riving knife for non-through cuts, the riving knife may contact the blade below the table. Remember that the riving knife can go in three positions: full up, halfway, and fully lowered. Furthermore, the bottom of the ZCI may interfere with tightening the height adjustment handle on that Bosch riving knife.

Here is a photo of it in the fully lowered position. You can barely see the dark black tip of the riving knife in this photo. (Sorry, but it is the only photo that I have of it, and I don't own that saw today. I took the photo for a description of how to make a ZCI for the Bosch table saw.)

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CharleyL
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The Micro Jig splitter is meant to be installed on the TOP of the table saw insert. It will not do you any good to install it on the bottom of the insert. They provide a guide to help you drill the mounting holes in your saw insert to be able to use their splitter.

The only time that a splitter or riving knife really has to work is when ripping pieces of solid wood with the grain. Stresses within the wood can cause the wood to bend as these high stress areas are cut into and the result can be the saw kerf closing back together behind the blade. When this happens, the wood can bind on the trailing edge of the rotating blade. The blade then wants to lift the wood and throw it at you "Kick Back". The splitter or riving knife prevents the kerf from closing back together behind the blade, so it prevents the rising teeth at the rear of the blade from catching and lifting the board being cut. Plywood and cross grain cuts do not have the same result when being cut, so do not need the function of a splitter or riving knife, but you still need some kind of pushing device that both holds down the work piece as well as pushing it forward.

A 1 foot long chunk of 2 X 8 with an L shaped step notch in it's bottom edge makes a pretty good sacrificial pushing device. It's large enough to be handled easily and it will hold the work piece down as well as push it forward through the blade and tall enough to keep your fingers 6" from the blade as you use it (a good safety rule to always follow - if your fingers need to be less than 6" from the cutter, stop and find another way). Narrow cuts that leave a kerf in the 2 X 8 do no significant harm, but eventually will require you to make a new 2 X 8 pusher from scrap. Scrap is free and making one only requires a few minutes time. A scrap piece of thinner material of this same size will work fine, but will likely need replacing more often. You should also never use your table saw with the blade height higher that what is required for the blade teeth to extend more than about 1/4" above your work piece.

The Micro Jig Grripper is another pusher that works well and it is adjustable to allow being used for cuts as narrow as 1/4", or 1/8" with an accessory 1/8" side piece. There are many versions of pushing devices, some DIY and some purchased. Which ever you choose, be certain that it can both hold the work piece down as well as push it forward. The single point "push sticks" do not hold the work piece down well and should not be your choice when ripping solid wood. I don't think they are safe enough to use on a table saw at all, but some argue this.

Charley
 
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