R4512 ZCI

How to make a Ridgid R4512 Zero Clearance Insert

DIY Zero Clearance Insert for a Ridgid R4512

Here’s a quick and easy way how to make a Ridgid R4512 Zero Clearance Insert.  All you need is some 3/16″ hardboard, screws (or carpet tape), and a flush trim router bit.

How to do it

Trace out your OEM insert onto the hardboard then cut it out slightly larger, leaving it 1/8″ or so bigger.  Mark, drill, and countersink  the insert mounting holes.  Dig through your hardware drawer and find some nuts for the OEM insert screws and mate the pieces as seen below.  You can use carpet tape to mate the pieces as well if you can’t find the nuts or choose to not screw your ZCI down.

R4512 ZCI

Using the OEM insert as a template, route the ZCI to size on your router table with a flush trim bit. I recommended drilling a hole similar to the original as well to help with removing the insert.  Mount the new insert blank to your table saw.  If you choose to go the “no-screw” route (not recommended), clamp a sacrificial board across the insert to hold it down.

R4512 ZCI

Turn on your saw and slowly raise your blade to full height.

R4512 ZCI

Now you can remove your new insert and elongate the slot towards the rear so that the splitter / riving knife can be used.

If all this seems to be too much of a hassle, you can always buy a Leecraft ZCI!

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6 thoughts on “How to make a Ridgid R4512 Zero Clearance Insert

  • Rick

    Thanks for the tip. I just bought a Ridgid R4512 and was going to buy a ZCI.
    1) Where did you get 3/16 hardboard? All I have ever seen is 1/8″
    2) Have you tried this to make one for a Dado set?


  • Bob

    Most people are using 1/2″ mdf or Baltic birch and routing out all the recesses. The concern is 3/16″ wood of any kind will have to much play or bend when running pieces over it. Have you experienced this at all?

    Second question: once you raised your blade through and completed the cut how did you elongate the back for the riving knife?

    Third question: did you keep screws in the insert during use as well or just when making your initial cut through the insert for the blade? Did you make a tab on the back like the stock insert? Ok that was a fourth question but I’m really interested in this method over all the others I’ve seen.

    Thanks for the post!

    • Shelby Merrick Post author

      There are no issues with play or bending, as there is never much force exerted in the insert. I’ve yet to require a full height cut so the riving knife hasn’t been an issue for me yet. As for screws, I usually keep them all in as the insert stays in my saw. I have another that I use for dado cuts as well. The factory metal insert pretty much stays on the wall. There’s no tab on the rear of the insert either, it’s a pretty simple design.