The jury is in on ZCI material

[Bill Huber]

The for what its worth department.

I have tried different materials for making my ZCI and have now settled on the one I really like the best.

UHMW
I bought some that were already fitted to my saw and all I had to do was run the blade up.

Pros:
They look good
They are smooth

Cons:
After being in the saw for 2 weeks they bowed in the center


Plywood:

Pros:
Very easy to work with
Cheap to buy

Cons:
You can not really tap it for a 10-32 set screw. You can screw the set screw in and it will hold but its not really tapped.
The surface is just not as smooth as the UHMW
Its light weight
Will not hold a spiral pin for a lock that good.

MDF

Pros:
Very easy to work with.
Cheap to buy
Machines really nice
Is very smooth

Cons:
You can not tap it for a set screw, again the set screw will screw in and hold but the hole is still not tapped.
Its light weight
I will not hold a spiral pin good at all, comes loose after awhile

Phenolic
Pros:
Looks very nice
Are very smooth
The machine really well
You can tap holes in it.
The hold a spiral pin very well

Cons:
They do cost more


So now I have gone to Phenolic all the way, they look and work very well. The cost is a little higher then MDF or Plywood but to me it is worth it.
I now buy a sheet of 1/2 inch for $24 and I can make 3 ZCI out of it, $8 is just not that much for a ZCI that will last forever.
They really tap well and with a drop of Blue Locktite the set screw hold great. I can install a spiral pin in the end as a safety so it can not come out in the back.

[Roger Warford]

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?

[Doug Shepard]

Bill
Have you tried Corian? I've got a couple small scraps I've been saving and wondered how they would work for a ZCI. The only thing I wonder about is how well it take threads. It would fall into the Pro side on the other aspects.

[Chris Padilla]

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?

[Bill Huber]

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?

Well from what I have seen the UHMW is the last thing I would use, it bowed down really bad, it was so bad that the ends came up above the top a little. I got them from Peachtree and thought they would be really good.


On the solid wood, I just never thought it would work very well in my case. My ZCI are only about 3/16 on the edges and I really don't think that would work very well with solid wood and its grain.

I am still a new with all this woodworking so it may be just fine.

[Bill Huber]

Bill
Have you tried Corian? I've got a couple small scraps I've been saving and wondered how they would work for a ZCI. The only thing I wonder about is how well it take threads. It would fall into the Pro side on the other aspects.

I was wanting to try some but just never took the time to run it down. I think it would take the treads really well as dense as it is.

I think I saw someone had used it on the Creek, I will have to see if I can find it.

[Bill Huber]

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 know what you are saying but I don't know the answer to it.

The air has to come from someplace or the the DC could not move it. On the other hand if you are ripping a wide board and cover up all the holes its the same thing.

With that said, I do remember before I got my ZCI installed on my new Jet contractor the old open slot did much better at pulling in the dust when you are just cutting a small amount off a board, like the edge.

So you just may want to give it a try and let us know what you find out. I just may have to try that with my old MDF ZCI.

[Sonny Edmonds]

I'm still with my MDF inserts and I'll tell you why,
I don't need jacking screws.
My ZCI MDF inserts are just proud of the actual surface of the iron, so I carfully sand them flush with my ROS.
Then I wax them generously with Johnson's paste wax and mark them for the blade they are made for.
Works for me.

[Chip Lindley]

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!

[Alan Schaffter]

A few more thoughts about MDF-

Leveling screws- use narrow head deck screws in a counter bored pilot hole. Grind the tips down a little.

Or, drill an oversize hole at the leveling screw location and glue in a piece of dowel for better screw gripping.

Go to your local counter fabricator and pic up scrap laminate to surface the MDF. I get stuff from their trash bin for free. I sometimes need to remove the adhesive, but it comes off very easily with Acetone.

You need more openings in your saw for DC take-up air than any throat plate provides. Most tables do not seal to the cabinet anyway. No cabinet-connected DC will pickup the dust coming off the top of the blade- it is being thrown by the teeth and gullets too fast above the wood for a DC to get it. You need over-blade dust pickup.

[Bill Huber]

I'm still with my MDF inserts and I'll tell you why,
I don't need jacking screws.
My ZCI MDF inserts are just proud of the actual surface of the iron, so I carfully sand them flush with my ROS.
Then I wax them generously with Johnson's paste wax and mark them for the blade they are made for.
Works for me.

That is what I thought about doing to start but what I found on my old saw was the point that the screws set were not all the same.

But I should have tried it on the new saw but I didn't, now I have all the ZCIs I need.

[Bill Huber]

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!

I don't think they make them thin enough, my ZCI is only 3/16 of an inch at the point I put the screws in.

One of the biggest reason for using the Phenolic is the fact that it will last for ever I think and I can tape the holes. Tapping the holes is nothing, a number 21 bit and 4 holes and then a 10-32 tape and its all done, when you are only tapping 3/16" it really goes fast.

[Josiah Bartlett]

You could just drill and tap the table for the set screws. Then you only need one set, and as long as you made all your ZCI's from the same batch of material you only have to adjust them once. If you don't like them you can always just screw them down to level.

[M Toupin]

$8 is just not that much for a ZCI that will last forever.

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

[Rick Lizek]

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