The jury is in on ZCI material

[Jim O'Dell]

Thanks for the link Rick! I had seen that before, but lost it. It is now copied and saved as a Word file. I'm thinking about building one, but I'm hesitant to use aluminum. Think I'll try it with Corian. I've got several pieces here that should work. Jim.

[Brian Effinger]

A big thanks from me too, Rick. That was a great article, and I'm now thinking of making one for my SC saw.

[Wade Lippman]

Thanks Bill! I've been looking for just such an evaluation. I keep hearing about folks using UHMW and wondered if it was worth it. What do you think about solid wood for inserts?

Mine sagged like Bill's. Won't do that again.

I have had good luck with teak. (have some small pieces with no other good use...)

[Bill Huber]

There's the fallacy Bill, a ZCI is a wear item, it needs to be replaced as the kerf opens up if you want to maintain that ZC. Most folks wait way too long to replace them. You should have a handful of spares around to replace them as needed. Throw in one for each of your dado sizes and at $8 a crack that gets expensive.

Ply and MDF work fine, put a drop of thin super glue in the holes and let it dry before you tap them. They will tap well and the threads will be fully formed.

Corian is an excellent ZCI material, smooth, taps well and it's free if you find a local counter top shop. They throw out tons of cutoffs and they will be more than happy to let you drag away their trash that they have to pay for by the load. It's all I use and I make 10-15 at a time so I never run out.

Mike

How will it open up if you are using the same blade all the time. Now I am not a contractor, just a hobbyist so that may make big difference.

[Bill Huber]

Aluminum with a replaceable insert is the best type insert...
Easy to make with standard wood tools...
http://www.woodcentral.com/articles/...cles_893.shtml

That is a great link and I have it bookmarked, thanks.

I just may have to make of those at some point.

[Greg Hines, MD]

As for tapping different materials for levelling screws, there ARE threaded inserts which might be easier to take out of an old insert and screw into a new insert than tapping. The correct size holes would be bored in new blank inserts all at the same time, and inserts added when replacement time comes.

A little bolt/nut jig could be made and kept handy for just this occasion. I believe four inserts could be twisted into their holes faster than tapping four holes. And, when time comes to remove the inserts from a ZCI to be trashed, just drive them on through the insert material with the bolt jig and a smaller nut. ...Just A THOT!

One other thing about this part:

If you bore the holes for the inserts all the way through, and install them with the hex head up, you can adjust it from above the table.

Doc

[J.R. Rutter]

Thanks, Bill. Grizzly had their blank inserts on sale way back when and I broke down and bought like 6 of 'em so I wouldn't have to make my own. I believe they are phenolic.

Not to wander too far off topic here but I think ZCI do a disservice the dust collection from within the TS. I've often wondered about drilling a buncha holes in my ZCI to faciliate better dust extraction. After all, you only need a very small portion of the throat plate to act as a ZCI...the rest is just, well, support I guess. Any thoughts there?

I found that one larger hole (like 3/4 to 1" ) worked pretty well. I put it where the dust angles off of a cut that is trimming an edge. Small holes don't allow enough air flow.

[Dave Trask]

I use Red Oak for my inserts.

Easy to machine
Doesn't warp
Don't need threaded inserts, oak taps like iron.


Dave

[Rick Lizek]

Aluminum and all non-ferrous works easy with woodworking tools.

[Karl Brogger]

Aluminum with a replaceable insert is the best type insert...
Easy to make with standard wood tools...
http://www.woodcentral.com/articles/...cles_893.shtml

That's a pretty good idea.




As far as dust collection goes, most saws have two giant holes in them for the tilt/lift handles, I wouldn't worry too much about it.

[M Toupin]

How will it open up if you are using the same blade all the time. Now I am not a contractor, just a hobbyist so that may make big difference.

Let me preface this by stating I'm only a hobbyist too, a couple of hours a week or so we're talking apples to apples.

The slot will open on you as it wears due to blade flex etc.

Try this; cut the kerf in 2 of your new ZCI. Hang one on the wall and don't touch it. use the other for 6 months.

Hit me back in 6 months and let me know if the kerf is still as tight as the one on the wall.

Mike

[Bill Esposito]

I've made and used ZCI's of MDF, birch plywood and phenolic and I've settled on plywood as my #1 and phenolic as #2.

I use the Microjig MJ Steel PRO splitter much of the time and MDF just doesn't hold it very well and I would not recommend using MDF with the MJ Splitter as a result of my tests. Plywood works pretty well provided I run some CA in the holes. If you are concerned about the MJ Splitter coming out then phenolic is the best. The MJ Steel Pro just cannot be yanked out by the work when it is installed in phenolic. I wouldn't use the older plastic MJ Splitter in phenolic because you will likely break and leave the legs in the holes...it holds that well.

You know, there's probably no reason you cant make the replaceable insert splitter using phenolic as a base material instead of aluminium. You could even make the insert out of phenolic if you were so inclined.

[Karl Brogger]

Just for my own curiosity. The only reason I used to run the zero clearance inserts was because of melamine. When the material has support, even that little bit from the angle of the teeth, you can get a fairly chip free cut. Is that the same reason you guys are doing it?

Its also nice when cutting small strips as the drop doesn't fall into the saw too.

[Sonny Edmonds]

Those have been around for quite a while. I won't use them.
I had a beautiful aluminum sheet on my downdraft table when I built it.
Nothing is more frustrating than aluminum pot marks on your wood.
Especially lighter woods like maple!
I did eventually replace the piece with 1/4" thick pegboard to get rid of the pot marks the aluminum would leave.
It may be a non-issue with your table saw. But in my shop aluminum anything is practically banned.
Except beer cans...

[Bill Esposito]

Karl, I think the ZCI helps improve the cut on just about any material which is why I use them.