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. :confused:
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. :confused:
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/shop/articles_893.shtml

[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/shop/articles_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/shop/articles_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. :mad:
Especially lighter woods like maple! :mad::mad:
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.

[paul dyar]

I make my out of oak. I drill and tap it, and it works fine for me.
Paul

[Will Overton]

I don't bother tapping my zci's. I use small, roundhead brass wood screws in the bottom. Yeah, it takes a little longer to tweak them since you've got to lift it out to turn the screw, but I've never had a problem. I've used plywood and mdf. When I recently gave my zipcode saw away it went with a bunch of blanks.

[Andrew Nemeth]

I'll stick with corian. Taps well, very flat, smooth, and scraps are cheap if not free.

Now, I was thinking about dust collection. What about enlarging the kerf on the waste side of the blade? This would allow much greater airflow around the blade but still fully support the finished piece.

[keith micinski]

I am not sure why everyone is worried about tapping the holes. I use plywood and just screw the leveling bolts from insert that came with the saw into the hole I drilled slightly undersized and they couldn't have been any better. Actually probably better then tapping them because the fit was tight enough that they weren't going anywhere with out a wrench.

[Van Huskey]

I like corian as well, if it wasn't free I would use phenolic.

[Will Blick]

The replacable angled wood insert is brilliant, hard to imagine no one is marketing a product like this..... no reason to make an entire plate cause one small areas gets removed...

Good point on the dust collection, a top unit like a shark gaurd would be ideal... otherwise, I would open up the slot after the cut point... different height blades would dictate different positions to open up... so try to keep blade at fixed height most of the time?

[Ben Martin]

I'll stick with corian. Taps well, very flat, smooth, and scraps are cheap if not free.

Now, I was thinking about dust collection. What about enlarging the kerf on the waste side of the blade? This would allow much greater airflow around the blade but still fully support the finished piece.

I can get Corian to tap, but the problem is that with the use of the saw, the set screws wobble loose causing constant readjustment. Do you have this same problem? I always am adjusting mine back to level...

[Zach Callum]

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.
Doug,

I have tried corian, and it works great!

[Thomas Hotchkin]

I can get Corian to tap, but the problem is that with the use of the saw, the set screws wobble loose causing constant readjustment. Do you have this same problem? I always am adjusting mine back to level...

Ben, use self locking set screws, works great Tom:)

[Trent Shirley]

I had been thinking about using corian myself but when I got a scrap piece it seems incredibly hard. Is it safe to machine in a planer to get the right thickness?

I have yet to find a source for scrap parts to make my inserts with. Just found the one small piece someone had laying around.

[Chris Padilla]

Thought I would point out that Paul Dyar resurrected a ~1.5 year old thread...still good stuff. :)

[Chris Padilla]

I had been thinking about using corian myself but when I got a scrap piece it seems incredibly hard. Is it safe to machine in a planer to get the right thickness?

I have yet to find a source for scrap parts to make my inserts with. Just found the one small piece someone had laying around.

Corian is fine to use ww'ing tools on...cuts nicely.

[Will Blick]

Forgot that Tru Cut makes em, sold at LV and other dealers....

but why NOT for the PM2k, sheeesh, not enough in the market yet???

http://www.leevalley.com/en/images/item/woodworking/saws/46j8510s1.jpg

[Alan Schaffter]

The replacable angled wood insert is brilliant, hard to imagine no one is marketing a product like this..... no reason to make an entire plate cause one small areas gets removed...



The original was designed and marketed by WoodDynamics, Norm used it for years on the NYW, but the company closed in '06. I suspect it was cost prohibitive from both manufacturing and retail price standpoints- it sold for around $120!

The biggest problem with that insert plate is that it was machined from a solid billet of aluminum which means high production cost (labor and material). Also, because it had a splitter slot there wasn't much material holding the halves together and keeping it rigid at the outfeed end (which is true for most insert plates and probably why the current one being marketed uses a rectangular cutout which doesn't run full length.

A few SMC folks have drawn the WoodDynamics design in various CAD programs over the years (Lee Schierer (http://70.169.135.35/showthread.php?t=10839) and Bruce Page (Unisaw insert halfway down the page (http://www.woodworkersworkshop.com/cadfiles/jigs.htm)) in AutoCAD and John Guerra in Solidworks) if you are interested in taking a whack at making one. Most folks made them with WW tools - it can be really scarey and result in snapped carbide router bits, trying to machine aluminum with woodworking tools- don't ask how I know. It is best made with something like a Bridgeport mill.

[Will Blick]

So who is making and selling it today?

Maybe they will expand the line? The design as-is seems ideal to me....

Agreed on the full length insert, hence why this drop-in replacement is a simple solution...

[Alan Schaffter]

Nobody is currently producing the WoodDynamics design- I believe it is available to anyone- I did an internet search and couldn't find any existing patents on it.

The Betterly Tru-Cut Insert system seems well built and if you use ZCI's regularly will pay for itself sooner than later. If there are any complaints against it they might be: you need to remove six screws to change inserts, if you can get phenolic or another rigid material it might be a bit harder to make your own inserts, there is an issue with certain types of splitters (MJ) and blade clearance (can't raise the blade full height), it doesn't fit all saws, and cost is $80 for the frame and $30 for a 4-pack of replacement inserts.

[Rob Young]

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.

Blade flutter is one way.

If you adjusted for an angle (using a different ZCI), then thought you came back to 90 but were just a smidge off.

You may think that ZCI isn't moving about in the slot but it is, just a little bit.

Getting a blade sharpened and re-using its old ZCI.

[Rob Young]

Some final thoughts:

I flip the insert over and get a second life from each one. Just wax the back side and tweak the levelers.

Never had much problem with the set screws in plywood. As mentioned above, a drop or two of CA down the hole and you can cut nice threads.

To start the slot for the blade I switch to one of the outside blades of my dado set but DON'T drive it all the way through. it only needs to come up about 1/2 way through the insert (just a couple turns of the crank) to cut sufficient clearance for my full 10" blades. YMMV

One way around the blade height versus bottom of insert problem is to just pass the insert over a straight bit on the router table and cut a groove. However this makes it harder to flip the insert later because now you have a groove on the top that can catch stuff. Fill it I suppose but now we are making a lot of extra work out of this ZCI.

[glenn bradley]

I've settled on 1/2 BB ply, 1/4-20 setscrews threaded into an under-size hole in the ply, flip for dual use, MJ Spliters, no failures. ZCI's are wear parts to me. They last till I do something that makes the offset inaccurate like re-align the saw, change things for a repeated operation, etc. I think I am on my 3rd set (one or two for each blade/operation) in this shop.

[Bill Huber]

Blade flutter is one way.

If you adjusted for an angle (using a different ZCI), then thought you came back to 90 but were just a smidge off.

You may think that ZCI isn't moving about in the slot but it is, just a little bit.

Getting a blade sharpened and re-using its old ZCI.

I guess the question is what is Zero clearance.

I just went out and checked mine, I put this one on in Oct. 2008 and you are right, it is not zero clearness any more. I can put a .009 feeler gauge between it and the blade on both sides.

But is .009 to much, will that really make a difference in the way my cuts come out?

In the 2 years I have been using this one I have gone back and forth from the rip to the the general blade and my plywood blade many times. I have cut a lot of angles and have had my general blade resharpened.

So I guess the bottom like is what is zero clearance to you.

[Alan Schaffter]

Some points to ponder-


To reduce/prevent chip-out the only place you need zero clearance is at/around the (carbide) tips of the blade where they go down and re-enter the table.

The clearance everywhere else doesn't need to be so tight since the only function there is to prevent big chips or slivers from wedging against the blade.

A ZCI works against dust collection. Standard throat plates are only slightly better.


If you have an enlarged, sloppy opening on your ZCI and it is made from a material that glue, epoxy, plastic adhesive, etc. will bond to (wood, phenolic, etc.) you can renew and return it to zero clearance quickly and easily. True up (and widen) the slot on your router table, then just glue in a strip of similar material closing the slot completely. Install the insert. Turn on the saw, and raise the blade to recut a new zero clearance slot. This can be done many times.

[Jim O'Dell]

I had been thinking about using corian myself but when I got a scrap piece it seems incredibly hard. Is it safe to machine in a planer to get the right thickness?

I have yet to find a source for scrap parts to make my inserts with. Just found the one small piece someone had laying around.

Trent, no need to plane it down. Just route a rabbit on the underside edge to the proper thickness. This will actually leave a little more meat to the ZCI to help keep it from breaking.
I used Corian to make a ZCI for my Ridgid contractor saw that has the replaceable inserts. It was a lot of trial and error getting it close to right. It works, but it's not perfect. And it is brittle. I've broken out the outfeed screw part of the Corian because it was too close to the outside edge. 161036 161037 Still works though.
I tried the dovetail inserts like the the original unit used, but never could get the tolerance right. When I saw the Tru Cut unit (also sold at Infinity Tools, and we get a 10% discount there!!) I changed the design to match.
Of course now I have the new TS, and need to do something for it. Nothing available for it commercially (except for the Grizzly blanks at 30 bucks each!!:eek:) so I will need to make one for it. And I'm out of Corian!!!:( Jim.

[Alan Schaffter]

When I saw the Tru Cut unit (also sold at Infinity Tools, and we get a 10% discount there!!) I changed the design to match.
Of course now I have the new TS, and need to do something for it. Nothing available for it commercially (except for the Grizzly blanks at 30 bucks each!!:eek:) so I will need to make one for it. And I'm out of Corian!!!:( Jim.

Jim,

Something to try:

With a pin or lip on the outfeed end to prevent it from lifting, couldn't you use rare earth magnets rather than screws to secure replaceable inserts like used by Tru Cut? That would make it incredibly easy and lightning fast to change inserts- just pop it out and pop a new one in!! (Boy, sometimes my brain is firing on 10 out of 8 cylinders! :D )

You would only need a simple template to crank out additional inserts. If the main insert was ferrous, you could drill and glue or use cup mounts to attach the magnets in the replaceable insert. If you still use Corian for the main insert you could mount the magnets and flathead screws for the other half the pair in either part of the assembly. It may have been a cost issue, but I'm surprised Tru-Cut didn't do something like that.

[Jim O'Dell]

Jim,

Something to try:

With a pin or lip on the outfeed end to prevent it from lifting, couldn't you use rare earth magnets rather than screws to secure replaceable inserts like used by Tru Cut? That would make it incredibly easy and lightning fast to change inserts- just pop it out and pop a new one in!! (Boy, sometimes my brain is firing on 10 out of 8 cylinders! :D )

You would only need a simple template to crank out additional inserts. If the main insert was ferrous, you could drill and glue or use cup mounts to attach the magnets in the replaceable insert. If you still use Corian for the main insert you could mount the magnets and flathead screws for the other half the pair in either part of the assembly. It may have been a cost issue, but I'm surprised Tru-Cut didn't do something like that.

Good ideas Alan. On the Ridgid, the factory outfeed tie down is a piece of spring steel that just slips under the lip at the back. Easy to make at the factory, harder to reproduce by an amateur. So I drilled a hole in the saw's back ledge and tapped it for a screw. The Grizz saw will be easier to do.
The only problem I have with the ZCI I built is that the inserts aren't a perfect fit. Good enough to work, but not the same quality fit as you would expect in a store bought unit. A CNC router system would make it more professional looking. Easy to reproduce extra inserts with a template bit on the router table. I ended up using 1/4" MDF with laminate glued to it. Came up to the perfect height I routed my recess at. :rolleyes: And slicker that the MDF would have been alone. It would be nice to have a screw holding the insert down at the side, but just not enough meat left in the Corian at that side to do it. I made mine where the inserts will do both regular blades and dados, thus the weird shape. Jim.

[Alan Schaffter]

A CNC router system would make it more professional looking. Jim.

I sent a query to my brother to ask him about making a Tru-Cut like throat plate from steel to hold rectangular inserts I will make (from plastic, Corian, phenolic, etc.) that are held in place with rare earth magnets.

He just got done refurbishing and converting a huge old Bridgeport mill to full CNC. While he mostly does aluminum, I think he can do steel, though it will be much slower. The experiment is worth his, er my time. :)

[Jim O'Dell]

Heck, I'd go ahead and use the aluminum! Jim.

[Alan Schaffter]

Heck, I'd go ahead and use the aluminum! Jim.

I really dislike woodworking stuff made from aluminum- it just doesn't hold up. I have scratches on my Unifence fence and rail. I have scratches and dings in the aluminum anodizing on my Woodpeckers router plate from the steel insert ring wrench hitting it. They wouldn't be there in steel. Wood doesn't slide on aluminum nearly as nicely as it does on steel.

[Glen Butler]

I am going to resurrect this old thread to say that you can tap MDF. What you need to do just before and after tapping is wick thin CA into the hole. Tap again. I usually wick CA twice and tap twice to get a good clean thread. I however do not like MDF for ZCI's; it's just too flimsy.