Beginner guide to making a zero clearance insert

[Derek Larson]

Ok I did a quick search on the forums but did not see a guide on this (although I am sure I just over looked it). I just happened to stumble across a guide to making a zero clearance TS insert, it then dawned on me how simple it is. Now I am very new to woodworking but I thought I would share this with other beginners. The problem I had figuring out was how to cut the insert to the exact same oval shape as the factory insert.

Start with plywood or stock that will sit flush with the table top ( in this guide they used 1/2" plywood) then with carpet tape, tape the factory insert to the plywood and trace the shape.
Next Rough cut the plywood with a bandsaw or jig saw.
Next Tape the factory insert back on and use a flush-trim router bit to trace cut the shape of the insert
And you should have an exact replica of the factory insert.
What I will do is cut the blade slot so it goes almost all the way out the back then I will glue a piece of wood that will stick up in the back to act as a splitter (not sure if there is a better way).

Anyway it is very simple and I feel stupid for not being able to figure that out on my own, it was very obvious.

[Greg Cole]

Ba-da-boom ba-da-bing.
FWIW, I have some made for various width dado's too. Handy dandy as all heck.
Don't forget to make a few for the miter saw if ya have one too. I seem to replace those more often with all the bevel cuts etc.
That method works for replicating many shapes.;)

Greg

[Prashun Patel]

That's not stupid. That's smart. Especially the part abt the splitter. Lots of people don't go the xtra step to put one on.

Make sure the splitter is 100% parallel to the blade else it'll draw the piece either toward or away from the fence, which can cause the the workpiece to contact the side of the blade and kickback or bind.

Also, some splitters can interfere with a cross cutting sled. If you need to remove it, you might consider ways to attach the splitter such that it can be removed. One design I like uses brad nails as 'dowels' that insert into the ZCI. The top ends are then carefully glued into the end of yr 1/8" splitter. This allows the splitter to be removed easily.

[Greg Hines, MD]

The only things I would add is that I made my ZCIs out of 1/2" MDF, which I think is a bit slicker than the plywood, and that you will probably have to rout or drill out points where it is supported around the table saw table, so that it sits flush or you can add leveling screws. For mine, I cut them out on the band saw, rout them flush, then put in a rabbetting bit and rabbet them all the way around. I make about 5 of them every time I ever make just one, so that I have extras. They are handy for dados or moulding head cutters too.

Doc

[Bruce Volden]

I, also, make my own ZCI's and have for years! I have some made of plywood, some solid wood, and several from solid surface material (Corian).

I also add some countrersunk rare earth magnets to assist in holding them in place!! This certainly beat having to deal with a "springy thing" that I with my old '70's era Craftsman TS. BTW-Craftsman TS was given away to make room for a NEW 764 Jet a few years ago (love it!) :D

Bruce

[Chris Padilla]

Micro Jig (http://www.microjig.com/MJ%20Splitter.htm) makes a dandy little $20 splitter that is well worth the money.

[Prashun Patel]

If you buy the microjig, gotta be careful which saw you have. Some don't have enough room on the ZCI btn the blade slit and the back edge to fit.

But I imagine that's only a prob for people with cheap tsaws like ME.

[Eric Gustafson]

My BIL gave me some polycarbonate "glass" to make ZCI's from. It works great. I inserted some rare earth magnets at either end, which work well to hold it down.

[Prashun Patel]

eric-
What's yr method for cutting polycarb? That is, if one does not have a bandsaw?
Can it be taken to a router bit?

[glenn bradley]

Good work Derek. I make them a half dozen or so at a shot once a few have worn out. Making six is just a smidgen more effort than making one. I write what blade they are for on the under side and have one for every blade and a few blanks ready to go. I use a few for repeated dado wdths as well. I drill all the holes required including a finger hole and keep a few 3/8"x1/4"x20 set screws around for levelers. The finger hole hangs them on a peg for storage.

I pre-slot the bottom with a spiral bit on the router table. When one gets too worn to be effective, I toss it and raise the blade through a new one. I also leave a little squirrel-tail at the back as a retaining pin. Like Chris, I use the MJ Splitters; cheap, quick and easy. Plus, they allow adjustment if you don't get it just right the first time.

[Eric Gustafson]

eric-
What's yr method for cutting polycarb? That is, if one does not have a bandsaw?
Can it be taken to a router bit?

I did use the bandsaw to rough it, but I finished the dimension on the router table with a template bit and the factory insert as a template. It came out perfect and cut very easily.