# Zero Clearance Insert material?



## Mbrockman5 (Feb 25, 2013)

I'm wanting to remake the ZCI's for my TS, but I'm not sure what material to make it from and could use some ideas. I used some scrap particle board that worked ok, but it starts to chip around the edges. 

I was thinking about something like this cutting board. 








I don't live very close to a Woodcraft store, and the local Lowes and Home Depot don't have anything that I think would work.


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## Sorrowful Jones (Nov 28, 2010)

Lowes sells thinner pieces of oak that will work.


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## RobinDobbie (Jan 31, 2013)

You could use UHMW like pictured, just make sure it's *not* a tight fit, or you're gunna have a bad time. You'll need to have set screws for side-to-side/front-to-back fitting as well as height. Thermal expansion is a big deal with UHMW-PE, from what I've read. 

Depending on your saw, you could also use melamine(sealed around the sides), or MDF topped with Formica(or equivalent). I wouldn't use these materials if the throat plate inset on the saw is shallow. My Ridgid and Delta have a nice 1/2" depth making it easy to make ZCIs. My Craftsmans have a very shallow inset. MDF is very weak inside, and if you route the material to thickness, you'll be sorry. A way around this is to use hardboard as the very top of the insert, and then you would glue thicker MDF to the bottom for strength. Just make sure the hardboard is the thickness you need so you don't have to remove thickness. As soon as you modify MDF or hardboard thickness, you've ruined it's rigidity. 

I've made a few ZCIs out of solid hardwood. As long as they aren't exposed to extremely high humidity, they're fine. My first oak ZCI warped and twisted, but I now have a sealed maple ZCI that seems to be working nicely.


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## jschaben (Apr 1, 2010)

Mbrockman5 said:


> I'm wanting to remake the ZCI's for my TS, but I'm not sure what material to make it from and could use some ideas. I used some scrap particle board that worked ok, but it starts to chip around the edges.
> 
> I was thinking about something like this cutting board.
> View attachment 92939
> ...


Hi - That cutting board is probably HDPE (Hi Density Polyethylene) and should work fine for a ZCI. UHMW is pretty spendy and not normally found in cheap cutting boards. Not really disputing Robins information but I use a lot of UHMW for various things so I checked the plastics technical information sheet at McMaster-Carr. The co-efficient of expansion for UHMW is listed as 0.000083 to 0.0002 in/F° which isn't a lot with the tolerances I normally work with. Water absorption is listed as 0 to 0.1%.:smile:


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## RobinDobbie (Jan 31, 2013)

I read an example where a 12" piece of UHMW grew .046"(3/64th) when the temperature rose just 35f from 65 to 100f. That's quite a bit more than .0002"/f. Lets say you made a "perfect fit" insert one night at 50, and you use the saw a few months later into summer, in the middle of the day at 100f. There's gunna be some warpage. But you're right, that's probably HDPE, not UHMW-PE. Either way, I think the stuff might be a mite more bendy than I'd like.


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## jschaben (Apr 1, 2010)

RobinDobbie said:


> I read an example where a 12" piece of UHMW grew .046"(3/64th) when the temperature rose just 35f from 65 to 100f. That's quite a bit more than .0002"/f. Lets say you made a "perfect fit" insert one night at 50, and you use the saw a few months later into summer, in the middle of the day at 100f. There's gunna be some warpage. But you're right, that's probably HDPE, not UHMW-PE. Either way, I think the stuff might be a mite more bendy than I'd like.


 Yikes! that's quite a bit of movement, about .0013/F°. Wonder what kind that was, there are several flavors; abrasion resistant, conductive, glass filled, oil filled.... etc, to achieve various characteristics. I didn't look at all of them, the basic stuff I use. Good info though, will keep that in mind next time I need some.:smile:


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## Al B Thayer (Dec 10, 2011)

UHMW doesn't machine well. You really can't sand it and it doesn't seem to cut and remain true. Costs a lot.

I just buy the one made for my saw(Unisaw) and get two ZCs out of one because I can turn it end for end and put another slot in it.

Al

Nails only hold themselves.


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## rbk123 (Jan 10, 2013)

There is a lot of good zci advice on here, do a search. Baltic birch is used a lot, phenolic, mdf and scrap hardwood as well. Depth of the throat really doesn't matter as you only need to route a lip for the thickness you need. I have a shallow throat with my 4512 and I use laminate flooring (Pergo) leftovers. Works excellent.


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## cabinetman (Jul 5, 2007)

Some saws can use ½" ply as an insert. Small screws on the bottom can act as levelers.








 








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## Al B Thayer (Dec 10, 2011)

rbk123 said:


> There is a lot of good zci advice on here, do a search. Baltic birch is used a lot, phenolic, mdf and scrap hardwood as well. Depth of the throat really doesn't matter as you only need to route a lip for the thickness you need. I have a shallow throat with my 4512 and I use laminate flooring (Pergo) leftovers. Works excellent.


Great Idea. That stuff should be pretty stable and tough.

Al

Nails only hold themselves.


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## kkalin78 (Dec 20, 2012)

I used ply, uhwm and mdf for ZCI on my 4512. Finally I stopped on mdf - cheaper, easy and quick make on router table (I did a template for it) Only one drawback of mdf is it's less durable and gets damaged quicker. But at same time it's easy to replace.


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## cabinetman (Jul 5, 2007)

Just a safety tip about getting the first ZC cut. With the blade all the way down, and the insert is in place, place a substrate of some sort over the wide side of the insert to hold it down. Clamping it to the table would be wiser than just holding it. Turn the saw on, and slowly crank the blade up until it is raised all the way, and then shut off.

If the saw fence makes contact with the table/insert, slide it over on top of the insert making sure it's in a clear path for the blade to rise.

*EDIT:* Many saws come with a ZCI made from very thin stamped steel or aluminum which gives room for the arbor nut/washer. If your new ZCI is thick or sits on the bed for the insert, check to see if the arbor nut/washer protrudes high enough when raised all the way up which may make contact with the bottom of the new insert. If it does, you may have to chisel/rout out an area to make clearance.








 








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## RonRock (Mar 27, 2014)

In another thread it was mentioned that solid surface countertop material (Corian) was used. Seems like a good material if there happens to be some on hand. Anybody have any input?


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## jharris2 (Jul 9, 2012)

Al B Thayer said:


> UHMW doesn't machine well. You really can't sand it and it doesn't seem to cut and remain true. Costs a lot.
> 
> I just buy the one made for my saw(Unisaw) and get two ZCs out of one because I can turn it end for end and put another slot in it.
> 
> ...



Um, I dunno...


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## Al B Thayer (Dec 10, 2011)

jharris2 said:


> Um, I dunno...
> 
> Video Link: http://www.youtube.com/watch?v=PgSvyMt1m60&feature=youtube_gdata_player


The material I have doesn't work this well. The material in the video doesn't look like Any I've seen. But hey.

Al

Nails only hold themselves.


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## jharris2 (Jul 9, 2012)

RonRock said:


> In another thread it was mentioned that solid surface countertop material (Corian) was used. Seems like a good material if there happens to be some on hand. Anybody have any input?


Corian is a great material for TS inserts.

It cuts and routs well and is tolerably flat.

It's great to drill and tap.

Its not subject to changes in humidity.

Its generally 31/64 thick so its the perfect thickness for my uni and I think it comes in around 1/4 as well.

A friend of mine with a small shop wants a very large RT that also serves as a work bench.













I got hold of this 3cm thick solid surface slab for him and I'm looking forward to helping him with the project.

I'm on his schedule so I'm not sure when we'll get started but its gonna be fun.


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## Al B Thayer (Dec 10, 2011)

This would be my second choice over one you would buy. I've made fixtures from Corian and my experiences have been that the material is not slick on wood at first. After use it seemed to get a little better.

I agree it does machine well and I would trust threads cut in it for most use.

Al

Nails only hold themselves.


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## Trav (May 30, 2011)

RonRock said:


> In another thread it was mentioned that solid surface countertop material (Corian) was used. Seems like a good material if there happens to be some on hand. Anybody have any input?


I have a couple made from corian. They work perfectly. The material machines excellent.


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## RonRock (Mar 27, 2014)

Cool. I'll have to check and see if I still have some leftover pieces.


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## BaldEagle2012 (Jan 25, 2012)

+1 for laminate flooring scraps. Works great, planes or joints very well, and has an already slick top.


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## Carvel Loafer (Dec 31, 2011)

3/8" Baltic birch fits perfect in my old Atlas TS. Always lots of scraps around.


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