Throat Plate Material

[Greg Peterson]

Been playing with making my own zero clearance throat plates for my Ridgid R4511. Oak is nice and stout but fluctuates a bit with the weather. Acrylic is stable but not quite rigid enough length wise. Both materials are 1/2" thick.

Any suggestions on what material that is very stiff yet stable?

[Tim Morton]

i use HDPE to make speaker baffles....easily machinable and VERY stiff. I have not tried if for ZCI, but its on my list.

[Bruce Volden]

Corian or other solid surface materials--they all come in at least 1/2" thicknesses. I have made several over the years and am still using them.

Bruce

[glenn bradley]

Been using 1/2" BB ply for years without issue. The ZCI's don't last years as the slot wears with the passing of sawdust and time. I make them by the batch and when I get down to a couple left, I make another batch.

[Bill Huber]

This gets ask every now and then, everyone uses what they find works best for them. I have never tried BB plywood or Corian. I use Phenolic and it works very well for me, it is not the cheapest but it last almost forever for me.

Here is a thread I put up over 2 years ago and it still stands for me.

http://www.sawmillcreek.org/showthread.php?101164-The-jury-is-in-on-ZCI-material&highlight=jury

[Cody Colston]

I use 1/2" Birch plywood with high-pressure laminate on both sides. It's the perfect thickness for my Griz 1023 without having to use leveling screws. A finish nail at the back keeps them securely in place.

Like Glenn, I make them in batches.

[Wayne Hendrix]

I also use Baltic Birch ply and make them in batches. I drill holes and add set screws to level them and instead of the nail at the back to keep it in place I drilled and tapped a hole for a second hold down screw diagonal to the first. Even with all the extra work it only takes me about an hour to make a batch. I made the last batch over a year ago and still have several un-used ones ready to go.

[Randy Dutkiewicz]

I guess I'm different in what I normally use compared to what most on here have stated (Baltic Birch), but all seem to be effective. I've always used MDF. I run the 3/4" in stock thru my thickness planer, then rout out the template to size and seal with poly. Never had any problems with using MDF, is stable (especially when sealed), and I can normally make a dozen which lasts me a long time and for whichever blade I'm using. Like the others, I put a small screw in the top of the throat plate to keep it from rising on me. Never had to use any leveling screws as I plane to the correct size:)

[Mark Godlesky]

Like Randy I use MDF but I use 1/2" and tap for set screws to level. Some I just wiped with BLO, others I spray painted to give me a lighter color. And like others have said make them in batches.

[Bruce Wrenn]

Like Randy I use MDF but I use 1/2" and tap for set screws to level. Some I just wiped with BLO, others I spray painted to give me a lighter color. And like others have said make them in batches.Plus 1. You can get about 84 from one 4 X 8 sheet. That's most likely a lifetime supply.

[Greg Peterson]

I like the phenolic suggestion. A consideration on this saw is the riving knife requires the blade opening to run from rear to front, leaving only a couple of inches or so to support one side of the plate. MDF would likely not hold up terribly well. Phenolic it is.

[Dave Cav]

I'm in the MDF camp, too, because that was what was handy last time I made a batch. I've used solid lumber, plywood, lumber core plywood; it all seems to work OK.

[Peter Quinn]

I'm using 1/2" MDF on a PM 66' but the throat opening is minimal, so its stiffness is no issue over that span. I've used QSWO, but stopped when it got stuck in the opening during a steamy week. Phenolic is event ess pleasant to work with than MDF, but it performs quite well for this sort of thing. I recall reading a description in an old WW text about " Packing the throat" on a large turn of the century TS. Basically when the blade slot got sloppy, you filled the hole with putty and raised the blade into it once hardened. If I were using phenolic I might consider periodically filling the blade slot with bondo or 5 minute epoxy to refresh that zci effect rather than remake given the expense and general nastiness of phenolic dust.

[Roger Eihausen]

I use this http://www.ptreeusa.com/uhmwproducts.htm on my R4512 saw.
The material can be made to size using woodworking tools. It is very slick and stable material.
Rog

[Jim Rimmer]

For those of you who use and/or recommend wood for the ZCI, what do you do about the anti-kickback pawls? Mine tend to dig into the wood when lowering the blade and then are wedged in and won't raise when the wood slides past the blade.

[Cary Falk]

I have hardwood plywood and these from rockler. With a 20% off coupon I see to get every week, they are reasonable.
http://www.rockler.com/product.cfm?page=17508&filter=zero%20clearance

[Trent Shirley]

Unfortunately those phenolic blanks are too small for his R4511. They need to be 14 11/16" long after being cut.
I have the same issue.
LeeCraft sells a throat plat for our saw which also matches the Steel City 35900. I plan to cut a section out of the blade area from one of these rabbiting both sides and then make some hardwood inserts with matching slots so they will slide into the throat plate. Then it is just a matter of making replacement inserts for the phenolic plate when needed. I could even make the inserts out of phenolic and being much smaller than a full throat plate can make a lot more of them with less material.
The slotted inserts will keep the whole throat plate solid and the inserts from coming out.



I have hardwood plywood and these from rockler. With a 20% off coupon I see to get every week, they are reasonable.
http://www.rockler.com/product.cfm?page=17508&filter=zero%20clearance

[Harvey Melvin Richards]

I used a piece of 1/2" aluminum, with a dovetail slot milled in it. The throat plates are replaceable hard wood inserts. I have at least a dozen plates for different blades and dado widths. I also have a dozen blanks waiting to be used. When an insert gets sloppy to a blade, it becomes a dado or angle insert.

http://i811.photobucket.com/albums/zz35/HarveyMelvinRichards/P4221461Large.jpg

[Bill Huber]

Unfortunately those phenolic blanks are too small for his R4511. They need to be 14 11/16" long after being cut.
I have the same issue.
LeeCraft sells a throat plat for our saw which also matches the Steel City 35900. I plan to cut a section out of the blade area from one of these rabbiting both sides and then make some hardwood inserts with matching slots so they will slide into the throat plate. Then it is just a matter of making replacement inserts for the phenolic plate when needed. I could even make the inserts out of phenolic and being much smaller than a full throat plate can make a lot more of them with less material.
The slotted inserts will keep the whole throat plate solid and the inserts from coming out.

You can get 11"x15"x1/2" phenolic sheets from Forrest Saw Blades Online for $26.

http://www.forrestsawbladesonline.com/category_72_LEECRAFT_Universal_Sheets.html

[Dave Cav]

TS. Basically when the blade slot got sloppy, you filled the hole with putty and raised the blade into it once hardened. If I were using phenolic I might consider periodically filling the blade slot with bondo or 5 minute epoxy to refresh that zci effect rather than remake given the expense and general nastiness of phenolic dust.

Cutting a strip of lath and gluing it in the ZCI kerf with epoxy works pretty well, too.

[Tom Blank]

Saw a comment from a fellow on another board that when an insert got too worn to work well, he filled the slot with Bondo, let it cure, and recut it. I suppose he was not referring to a MDF or ply insert.

[Greg Peterson]

The R4511 has an extra long throat.

Found a 1/2" x 12" x 24" sheet of phenolic at Amazon for $36, free shipping. That will make three inserts!

[Terry Beadle]

If you can find some, osage orange is very good for ZCI's.

I've been using a cherry one and it's worked well so far ( 4 yrs ).

[Randy Dutkiewicz]

The R4511 has an extra long throat.

Found a 1/2" x 12" x 24" sheet of phenolic at Amazon for $36, free shipping. That will make three inserts!

...or go with the MDF and get about 80 of 'em out of a 4 x 8 sheet for about 20 bucks like Bruce said...:)

[Trent Shirley]

I got impatient and gave in and bought the throat plate at WoodCraft for $29. I do not get the extra to play with but it is pre-cut for my purposes including the riving knife slot.
My intention is to cut a slot out of the front after I do some measurements to determine the placement and size based on 0 to 45 degree tilt. Then I will machine a rabbit on both sides, top and bottom. I will make replaceable inserts by cutting to correct width and routing a groove to match the throat plate to keep it firmly in place.

Others have used dovetails but I would imagine it would be a lot more difficult to cut initially and to line up correctly when making new blank inserts. I do not think I will have an issue with the throat plate spreading apart in the hole so the slots should be perfectly acceptible and easy to machine.

The only issue I may have is the riving knife I use will not fit through the slot for the splitter unless I cut the rest of the way through from the back which would weaken the throat plate or cut the rest of the way through to the saw blade slot which would do the same to a slightly lesser extent.
My thought is to attach a cable to the riving knife release and make a push button on the cabinet to allow me to insert or release the riving knife without removing the throat plate.

Anyone do something similar?


The R4511 has an extra long throat.

Found a 1/2" x 12" x 24" sheet of phenolic at Amazon for $36, free shipping. That will make three inserts!

[amiel gernentz]

get a plastic cutting board at dollar store or wallyworld cut to fit the opening and drill and install your leveling screws, run screws in til just peeking thru then put a rare earth magnet on each screw and install and tweek leveling screws, magnets stay in place when removing insert to change blades etc. magnets keep insert from tipping when ripping narrow boards, very little cost been using my first one for 2 years now and works like a charm

[Karl Card]

Id say I learnt alot of this thread. I just bought a Delta 34-350 ts and it came with a STEEL insert plate... that scared the crap out of me.... I am getting a 7.5 hp motor for this thing and while waiting to get my motor I have been trying to think what I am going to use for an insert plate... Well I just happened to have quite a bit of corian hanging around and I think I will try it. My next choice would be phenolic.

Good post

[Dave Cav]

Id say I learnt alot of this thread. I just bought a Delta 34-350 ts and it came with a STEEL insert plate... that scared the crap out of me.... I am getting a 7.5 hp motor for this thing and while waiting to get my motor I have been trying to think what I am going to use for an insert plate... Well I just happened to have quite a bit of corian hanging around and I think I will try it. My next choice would be phenolic.

Good post

The 12/14 table saw comes with a steel insert because it's an industrial saw and the blade runs very close to the right hand side of the blade opening. When you make throat plate for this particular saw, the part of the insert to the right of the blade will be very thin and fragile, so Delta decided to go for durability over precision. I made a ZCI for mine out of a scrap piece of lumber core teak plywood, and it's worked OK so far, but I do all my really precise work on the Powermatic. I would be leary of making a ZCI for this particular saw out of any composite material like Corian, MDF or particle board, as you will probably break the right side section and then the gap will be worse than where you were before. I'd suggest a hardwood plywood, something like Appleply, lumber core plywood or solid wood. The phenolic should probably work, too.

[phil harold]

I got three out of a plastic cutting board that cost 7 bucks added a couple set screws for perfect adjustment

I made these 15 years ago and have not needed to use the third one, yet...

206042

[Dave Cav]

The 12/14 table saw comes with a steel insert because it's an industrial saw and the blade runs very close to the right hand side of the blade opening. When you make throat plate for this particular saw, the part of the insert to the right of the blade will be very thin and fragile, so Delta decided to go for durability over precision. I made a ZCI for mine out of a scrap piece of lumber core teak plywood, and it's worked OK so far, but I do all my really precise work on the Powermatic. I would be leary of making a ZCI for this particular saw out of any composite material like Corian, MDF or particle board, as you will probably break the right side section and then the gap will be worse than where you were before. I'd suggest a hardwood plywood, something like Appleply, lumber core plywood or solid wood. The phenolic should probably work, too.

And I just remembered another challenge with making a ZCI for the 12/14" Delta table saw. The 12" blade does not retract far enough down to be able to drop the uncut insert in and then raise the blade through it; the blade will hit the insert before it fully seats. You could make the initial cut using a 10" blade IF you have a 10" blade with a 1" hole in it, or if you have the auxiliary 5/8" arbor stub. Or you can carefully drop the uncut ZCI down onto the spinning blade. I've done that a few times but it's not a real relaxing job. You could probably also use a slotting bit in a router table to make a starter slot, but getting it located correctly would be fussy.

[Greg Peterson]

I got three out of a plastic cutting board that cost 7 bucks added a couple set screws for perfect adjustment

I made these 15 years ago and have not needed to use the third one, yet...



Those look nice. Unfortunately on the R4511 there are two matters that prevent me from using the material that has served you well. First, the length of the throat is almost 15 inches. Second, the slot for the blade has to continue all the way to the rear of the plate. The riving knife on the R4511 has to be installed prior to setting the throat plate in place.

I'll be reporting on the functionality of the phenolic once I get it.

[phil harold]

. The riving knife on the R4511 has to be installed prior to setting the throat plate in place.


whats a riving knife?

lol
or blade guard?

[Karl Card]

Oh me, that does make sense. I will have to get out my kryptonite and make one...lol



The 12/14 table saw comes with a steel insert because it's an industrial saw and the blade runs very close to the right hand side of the blade opening. When you make throat plate for this particular saw, the part of the insert to the right of the blade will be very thin and fragile, so Delta decided to go for durability over precision. I made a ZCI for mine out of a scrap piece of lumber core teak plywood, and it's worked OK so far, but I do all my really precise work on the Powermatic. I would be leary of making a ZCI for this particular saw out of any composite material like Corian, MDF or particle board, as you will probably break the right side section and then the gap will be worse than where you were before. I'd suggest a hardwood plywood, something like Appleply, lumber core plywood or solid wood. The phenolic should probably work, too.

[George Gyulatyan]

Or you can carefully drop the uncut ZCI down onto the spinning blade. I've done that a few times but it's not a real relaxing job.

That sounds dangerous. This is how I cut the slot on my Jet ProShop which has the same issue with it's 10" saw as yours with the 12":

Put the original factory throat plate in the opening.
Backed out the set screws to get the plate lower than the table top.
Put my blank on top of the factor throat plate, and since it was recessed, the opening naturally centered it where it was supposed to be.
Used a hardwood caul to clamp the blank down.
Turned on the saw and slowly raised the blade enough to peek through the blank.
Turned off the saw, took the factory plate out, put my now slotted blank in, clamped it back down with the caul and raised the blade all the way through.
To cut the opening for the splitter, I again put the factory plate in, put the ZCI on top with the blade raised so I could reference the exact spot where the ZCI would be, adjusted the fence so it touched the ZCI, then took the ZCI off the blade, turned on the saw, and cut the splitter slot in the back, which is now exactly inline with the blade slot.

I am currently using UHMW, but have bought a couple of phenolic blanks from Rockler, with an eye out to making something similar to what Harvey has done with aluminum. I've decided to go with phenolic, becuase quite frankly cutting aluminum scares the bejeezus out of me, plus the ProShop requires some cutouts in the bottom of the plate, and this would be a PITA with aluminum, even if I wasn't scared of it :eek:

Overall I like UHMW, it's slick and stable, but it's definitely not as stiff as phenolic.

[Harvey Melvin Richards]

When I start a cut in my throat plates, if the blade won't go low enough, I use a smaller blade, like one side of my dado. I also put the fence over the plate, but out of the way of the blade. I don't want anything flying at my head.