ZCI With Riving Knife? Photos Anyone?

[Bill Space]

Hi,

I have the materials to make Zero Clearance Inserts for my Grizzly 1023RLWX (both 1/2" micarta and lexan) but noticed that there is probably not more than 1/8" of material left at the back end of the insert, once a cut is made in it to allow the riving knife to pass through it.

Just wondering what you guys have done when using a ZCI with a riving knife.

I can envision somehow making a metal strap that connects the two "halves" of the back end of the ZCI, or maybe that is not necessary, but it sure seems to my mind that it would be.

Any pictures or descriptions of how you have addressed this issue would be greatly appreciated!

Bill

[Shawn Pixley]

I can't speak to the Grizzly, but on my Sawstop the ZCI doesn't connect at the back. It is supported and locked in to the CI tabs on the top. I can't imagine that yours wouldn't work similarly.

[Bill Space]

Hi Shawn,

The opening on the standard insert on my saw, through which the saw blade and the riving knife protrude. extends towards the back to within 1/8 inch of the cast iron table. That is, the back of the standard insert is only about 1/8 in thick directly behind the riving knife.

I was wondering how to make the ZCI strong enough in this area.

Do you mean your ZCI is slotted from some point in the front, all the way to the back, sort of like a U shape with a very narrow space between the two sides, and the opening to the rear.

On my saw the insert is held from falling through the hole by four tabs, but there is nothing to hold the two sides apart, except for the strength of the material the ZCI would be made of.

Nothing locks the insert on my grizzly in place aside from the tabs that hold it from below, and the fit of the insert within the hole in the table.

What I was trying to ask about was how people are using homemade ZCIs with their riving knives, as it looks like without something to hold the back halves apart, there could be opportunity for the slot to close on the riving knife, and the ZCI to lift when the blade is raised.

Probably over-think on my part, as I doubt this will be an issue with micarta or lexan 1/2 inch thick...

Bill

[Shawn Pixley]

Bill, yes after the initial cut, the insert would look like a big "U" . It comes with a cut through for the riving knife and you lift up the blade to cut the ZCI portion. My SS has the older style method of attaching the ZCI to the top (leveling screws and lockdown tabs and one recessed screw in the front to lock it down.

Here is a picture of the bottom of the orginal style (before the saw cut).

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There is no connection on the back side. Each wing of the top of the "U" has a supporting tab. Really the back portion of the throat plate isn't carrying a significant load. The stock is largely supported by the CI table.

[Bill Space]

Thanks for taking the time to explain this Shawn. I had always seen ZCIs with material in front and in back of the blade and I think that was what I was expecting to have when I made some for the saw with a riving knife.

What you said makes total sense. Thanks for including the photo!

Bill

[Cary Falk]

Bill,
I have the G1023RL and use a phenolic(and some plywood) ZCI . I will try to remember to snap a few pictures of it when I get home. Cary

[scott spencer]

I've have a Shop Fox 1677 with a B-OR-K riving knife that's like the older G1023SL. I use phenolic inserts and extend the kerf slot just far enough back to allow the knife to pass.

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