Zero Clearance Insert and Riving Knife

[Randy Klein]

I've been researching ZCI's and almost all examples do not show how to include the riving knife. I have a Grizzly G0690 and looking at the stock throat plate, the cutout for the riving knife makes for a thin back end. I'm concerned that may be too thin for some materials like wood, MDF, ply, phenolic, etc.

I have found a commercially made one for the new Delta:
new_delta_zero_details.gif
and it shows a reinforced area behind the riving knife cutout.

Has anyone made a ZCI that included a cutout for the riving knife? Does it need to be reinforced?

[Pete Janke]

I just made two ZCIs for my G0691. One was made out of 3/4" MDF and needed more work. The other was made out of two pieces of laminate flooring and was an almost perfect height. I used a forstner bit mounted in the drill press to remove material from the bottom of the plates to make them sit properly and to drill all holes. They work well. Since the riving knife is held by the saw, no additional bracing was needed.
ZCI 3.51.jpgZCI 4.51.jpgZCI 2.51.jpgZCI 1.51.jpg

[Chris Ricker]

Randy;
I've made several MDF ZCI's for my GO651 and had no need for extra reinforcements. FWIW
CR

[Gene Waara]

......to make them sit properly and to drill all holes. They work well. Since the riving knife is held by the saw, no additional bracing was needed.
ZCI 3.51.jpgZCI 4.51.jpgZCI 2.51.jpgZCI 1.51.jpg

Not to highjack the thread, but my 690 insert was warped when my saw arrived so Griz sent me a ZCI since the inserts were backordered. I was able to rout the ZCI to allow for the riving knife but I am unhappy with the way the insert sits on the table. If I tighten the allen bolt on the front of the insert the back rises above the table. If I loosen the bolt the insert "wobbles " in the table cavity. There is no mention in the manual regarding troubleshooting the insert. Am I the only one with this problem?

[trevor adair]

I bought the G690 3 months ago and they included the ZCI. It is in my saw 90% of the time (other than angle cuts and dado) and I have had 0 problems with it.

[david brum]

No problem cutting a slot for a riving knife in a ZCI. Worst that can happen is cracking the little remaining area between the saw kerf and riving knife kerf. I'll bet you've got some glue that would fix that.

[keith micinski]

When I cut the zero clearance insert for my new 1023 it left very little material left behind the throat plate but it hasn't caused any problems. I did have a problem getting the gap wide enough in the very back so it didn't interfere with the riving knife.

[Randy Klein]

That's good to see. I guess I'll tackle one this weekend.

[Cary Falk]

When I cut the zero clearance insert for my new 1023 it left very little material left behind the throat plate but it hasn't caused any problems. I did have a problem getting the gap wide enough in the very back so it didn't interfere with the riving knife.

I used a 1/4" router bit to cut the slot for the riving knife. I cut it long enough to completely clear the front of the knife. The gap will be a little bit wider at the rear of the blade but that shouldn't matter.