# Table saw inserts



## qulevrius (Mar 18, 2019)

After 2 months of dedicated searching, I was lucky to find a barely used Delta 6000-series portable table saw, for a bargain of a price. The guy I bought it from, didn’t even adjust the throat plate; it was mounted to the table with the adjustment screws. Anyway, 1st order of business was to replace the original plate with ZC inserts. I decided to be fancy and make them out of a Lexan sheet. Unfortunately, the Lexan proved to be too thin at 0.093” and I couldn’t counterbore the holes for the screws. Decided to try the plate without retainers anyway. Stood clear to the side, started the saw. As expected, the blade immediately kicked the plate off.

My question is, did anyone try to make Lexan inserts for Delta saws and if so, how did you secure it ?


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## kp91 (Sep 10, 2004)

I'm cheap, I use MDF or Ply. did you put the pin in the end of the piece to keep the back end from lifting up? If your piece is real thin, you may have to had a 'hook' on the bottom side on the back end to keep it from lifting up.

I have seen youtube videos where folks have made them from PVC pipe, HDPE cutting boards, aluminum, and even cast them in resin.

If I was going fancy I would use aluminum, but maybe a bamboo cutting board as well!


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## qulevrius (Mar 18, 2019)

Yep, I’ve seen all those videos. And no, I haven’t put a back piece in the insert because it’s too thin. I plan on getting a cheap cutting board from Walmart and making the inserts from it. Will post updates.


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## kp91 (Sep 10, 2004)

You really need something on the back. If you epoxy a tab on the underside it might work. My big concern is an insert that thin might flex a little bit in use.

If you look at the pictures of my dado set insert, that one little bit of a nail on the back end does 99% of the holding of the insert in position, counteracting the blade wanting to lift it up out of the table. I also use small nylon set screws as leveling feet and on the sides to keep the insert snug and centered in the table. They are cheap and effective.

https://www.amazon.com/uxcell-M5x10...on+set+screw&qid=1557007552&s=gateway&sr=8-16


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## Herb Stoops (Aug 28, 2012)

Keep it simple, use the one that came with it go Fast Cap special,works great.

https://www.fastcap.com/product/zero-clearance-tape

Herb


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## JOAT (Apr 9, 2010)

qulevrius said:


> My question is, did anyone try to make Lexan inserts for Delta saws and if so, how did you secure it ?


Nope. Did make several from 1/4" plywood. Apparently I made them wrong, according to the videos, and all. Made them before I even knew there were instructions on making them. I cut out the pieces to fit the saw, thinned them to be level with the top of the saw. Set one in place, held down with a piece of wood, turned on the saw, raised the blade, and cut a zero clearance insert; repeat untill all are done. When I change out, put a new one in place, raise the saw until both ends are barely clear, turn on the saw, cut wood. Held in place by their weight. Never had any issues with any of them.


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## CharleyL (Feb 28, 2009)

Since my Unisaw doesn't drop a 10" blade completely below the bottom of a new ZCI, I usually begin the cut by putting a 7 1/2" blade on the saw. Then I clamp a scrap of 2 by lumber to the fence and position this scrap wood next to the blade location and very close to where the blade will come up through the ZCI to hold the ZCI down while I raise the blade up through the ZCI. Then I start the saw and slowly raise the blade. Once up up through the ZCI. The blade is then lowered and the saw turned off. I then replace the 7 1/2" blade with the desired 10" blade, and repeat the process of turning the saw on and slowly raising the blade, but this time raising it to as high as I think I will ever use it. Then I again lower the blade and turn the saw off. I then get the correct Allen Wrench and level the ZCI with the 4 set screws that I have previously installed in the ZCI. I then remove the ZCI and write on the bottom of it which blade I have made it for. 

I always use the same blade with it's mating ZCI, so as not to have the slot any wider than that particular blade. This is why I have about a dozen in the drawer next to the saw at any given time. I also keep several blank ZCI's that I've previously made in the drawer, so I always have a new one ready in case I buy a new blade or decide that one of the blades has damaged it's mating ZCI, so I can replace it quickly. Whenever I find that I only have a couple of blanks left, I make time soon after to find some suitable scrap and make about 6 new ones to put in the drawer. I never want to be completely out of ready-to-use blank ZCIs. Most of my shop made ZCIs have been made from Corian counter top sink hole scrap or 12 mm Baltic Birch. 

I don't think I've ever made any from Lexan, but it should work fine. Just use the fence, a clamp, and a scrap of 2 by wood to hold the ZCI down while you cut the blade slot in it. Use a smaller diameter blade to start the slot if the lowest position of your blade still touches the bottom of the blank ZCI.

I just came into a deal to buy some phenolic blank ZCIs for my Unisaw and bought 8 of them for $5 each, So I doubt that I'll be making any myself for a while They even came with the height adjusting set screws.

Charley


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## JFPNCM (Dec 13, 2009)

If all else fails, check out Lee Valley. Spendy but they fit.


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## DaninVan (Jan 1, 2012)

It's just an insert. make lots and make 'em cheap. 
Like Doug, i just use a finish nail at the rear and nip it to a short stub.


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## woodknots (Mar 7, 2012)

I've made mine from 1/4" mdf - same process as Charley - use a 7 1/4" blade to start then switch to a 10" blade. A small brad nail in the end to keep it from flying up. For leveling, I use small 3/8" screws and adjust to fit.


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## ger21 (Feb 10, 2019)

I make mine on my CNC, and route a blade clearance pocket on the back, so I can safely turn on the saw with a 10" blade. I do rest the fence over it when raising the blade. 

I would never use a plastic like Lexan or Acrylic.


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## thomas1389 (Jan 4, 2012)

Mine are plywood. Never a problem. A brad in the end to hold it down and adabba hot melt glue in each corner to level it. Just a question: can you get thicker lexan?


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## DesertRatTom (Jul 3, 2012)

The plastic cutting boards work well, but I prefer 12mm BB ply--don't like the plastic sticking to my blades.. I generally cut to width on the table saw, then round it with the band saw, also use the BS to cut the slot for the riving knife. Could use the router with a trim bit using the original insert as a template, but I'm happy with the band saw results for now.

For dado stacks used for rabbets, I just stack the blades and cutters without shims, so it's always the same size. For rabbets, you are burying the blade in a temporary fence anyhow, You expose only the amount needed to cut the rabbet. So for that purpose I can use the same insert for a long time. 

Never thought to put a finish nail in as a hold down. Thanks for that, although my inserts never lift out. I could just glue on a small tab to do the same thing, since the opening for the riving knife cuts all the way to the rear edge of the insert. Two tabs would keep one from flexing lower than the other. 

I usually use a 2x over the blank insert to really hold it down. I often just use a little tape to level because the depth of the insert opening is very close to the 12 mm thickness of BB.


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## qulevrius (Mar 18, 2019)

thomas1389 said:


> Mine are plywood. Never a problem. A brad in the end to hold it down and adabba hot melt glue in each corner to level it. Just a question: can you get thicker lexan?




I can, but it’s not gonna be cost effective. An 8x12x0.093 Lexan is ~$9, but they don’t sell 0.12” or thicker Lexan in small strips. I’ll end up paying upwards of $80 something for a 12x24 sheet. It’ll be cheaper just to buy phenolic inserts from Peachtree or Leecraft.


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## bfblack (May 2, 2012)

Here is a photo of the under side of the throat plate I made from 12 mm (1/2") Baltic Birch plywood. The throat plate blanks were ripped to the desired width and a pattern bit was used to make the rounded ends. There are five levelers made from 1/4"-20 x 1/2" long set screws. Drill a through hole so that the set screws can be adjusted from above. I don't remember the hole diameter appropriate for the set screw creating it own female threads; experiment a little bit. The safety tab for keeping the saw blade from throwing the throat plate in your face was made from a 1"x1" L bracket from Ace Hardware; one end was shortened. My design was inspired from the attached article in Fine Woodworking. Much to my surprise, the FW article did not discuss the safety tab. Unless you have a CNC (which I do not), cutting the so called zero clearance slot will likely involve starting with an 8" blade followed by a 10" blade. This may compromise the quality of the blade kerf slot.


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## qulevrius (Mar 18, 2019)

bfblack said:


> Here is a photo of the under side of the throat plate I made from 12 mm (1/2") Baltic Birch plywood. The throat plate blanks were ripped to the desired width and a pattern bit was used to make the rounded ends. There are five levelers made from 1/4"-20 x 1/2" long set screws. Drill a through hole so that the set screws can be adjusted from above. I don't remember the hole diameter appropriate for the set screw creating it own female threads; experiment a little bit. The safety tab for keeping the saw blade from throwing the throat plate in your face was made from a 1"x1" L bracket from Ace Hardware; one end was shortened. My design was inspired from the attached article in Fine Woodworking. Much to my surprise, the FW article did not discuss the safety tab. Unless you have a CNC (which I do not), cutting the so called zero clearance slot will likely involve starting with an 8" blade followed by a 10" blade. This may compromise the quality of the blade kerf slot.



I made a blank insert out of a 1/2” today. Used the original plate as a template, cut it with a top bearing straight bit. Haven’t gotten any further thus far, because the spade bits I have are too dull for ply & are burning the wood instead of cutting it, and the forstner bits haven’t arrived yet. The blade on my saw retracts out all the way, but I’ll need to make a clearance for the arbor housing. Will update as soon as it’s done.




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## CharleyL (Feb 28, 2009)

I never said what I use as the hold down for my inserts. Since I do quite a bit of metal working as well as woodworking, I've been using small diameter roll pins instead of finishing nails, I guess because I have a good assortment of them. Either will work the same. It doesn't take much to hold the inserts in place, but things can get real exciting if there isn't something included in the design for this.

Charley


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## qulevrius (Mar 18, 2019)

Still waiting on the forstner bits.


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## coxhaus (Jul 18, 2011)

I used a 7 1/2 inch blade on my new unisaw table saw insert. I then tried to switch to a 10 inch blade but the 10 inch blade was a lot thicker so using the small blade did not really help. How are you guys handling that? I can manually cut it but is there a better way?


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## qulevrius (Mar 18, 2019)

coxhaus said:


> I used a 7 1/2 inch blade on my new unisaw table saw insert. I then tried to switch to a 10 inch blade but the 10 inch blade was a lot thicker so using the small blade did not really help. How are you guys handling that? I can manually cut it but is there a better way?




Drill a start and end point & make a mortise with a band saw ? Or just a dado with the smallest router bit you have.


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## bfblack (May 2, 2012)

Following the suggestion in the Fine Woodworking article attachment from my earlier post, consider using double sided tape to attach your new insert blank to the original insert that came with the saw. This should allow you to use a 10" blade to cut the kerf slot. I have not tried this myself.

Another suggestion is to bevel the edges of the kerf slot on the underneath side. If you look carefully at the photo of my earlier post, you can see the beveled edge. Otherwise, there is a tendency for the new insert to be lifted up as you raise the saw blade.


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## qulevrius (Mar 18, 2019)

So, these are my final thoughts on making the inserts with minimal investment:

1) The only 3 tools needed are a table/miter saw, a router (preferably mounted) and a drill. For the router, the required bits are a flush trim, a guided rabbet & a straight (anywhere from 1/4” to 5/8”, bigger bit just needs to be more careful with).

2) Avoid cheap Chinese plywood.

How did I make it:

Cut the stock, mounted the original plate on one, trimmed it with a flush trim until identical - that’s the template. Used the newly made template to cut a bunch of blank inserts out of a 1/2” ply.

Tried to drill out the mounting legs clearance with a forstner bit, but quickly realized what a pain in the ass it is. Took it to the router table instead & used a 1/2” straight bit to clear out the bottom contours. Then switched to a guided rabbet & cleared the edge for the arbor housing. Finally, drove a finishing nail in the back to make a latch.

After that it was as easy as swap the 10” for a 8” dado, clamp the fence over the new plate & make an initial cut. Unfortunately, at this point the crappy Chinese ply chipped at the edge of the plate. 

But all in all, now that I have the template & figured out the workflow, I’ll make a trip to Walmart for a cheap polycarb cutting board & put it to good use. Will post pictures with final results.


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## qulevrius (Mar 18, 2019)

Update: the plastic insert isn’t done yet, but in the meantime I took DaninVan’s advice and made the essential inserts out of a 1/2” MDF. Will most likely do the polycarb one over the weekend.










The ZC doesn’t really need a safety pin, the riving knife won’t let it fly off. Put finishing nails in the dado inserts, just in case.


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## qulevrius (Mar 18, 2019)

The experiment is over. 

It’s fair to say that it wasn’t a complete failure, but at the same time I wouldn’t call it a success. The fatal issue with plastic inserts is that regardless of the material’s thickness, once the kerf & riving knife slots are cut, the tail end will inevitably sag. The only solution to it is to use something incredibly durable, like a military grade polycarbonate, but then the sheer cost of it makes commercial inserts look like freebies. 

Otherwise, MDF is the best bang for the buck. For $9 a sheet of 2’x4’x1/2”, one can stock up on inserts for years. But, I’m sure you all already knew that.

Regardless, I’m glad I had the opportunity to finalize the concept & am sure that someone down the road will find this information useful.


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## tomp913 (Mar 7, 2014)

coxhaus said:


> I used a 7 1/2 inch blade on my new unisaw table saw insert. I then tried to switch to a 10 inch blade but the 10 inch blade was a lot thicker so using the small blade did not really help. How are you guys handling that? I can manually cut it but is there a better way?


I found the same problem when making a ZCI for a full thickness blade - the solution was to use the outer blade from my dado set, works perfectly so I use it for all blades now. The secret is to only raise the dado blade until it just starts to break through the upper surface - this will give enough clearance on my Unisaw to allow cutting the final slot with the 10" blade being used.

Another trick that I read somewhere (but didn't make a copy of the article, just have remembered it over the years) is for adding the end slot for the splitter/riving knife. With another insert in the saw and the blade raised, rotate the new ZCI end for end so that it's in the correct position and drop it over the blade. Move the fence so that it's tight against the edge of the ZCi and lock the fence in place. Take the ZCI off the blade, flip it back over so that it's "upright", turn on the saw and cut the slot for the splitter - it will be exactly in line with the saw blade. A little easier than cutting it on the router table.


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## tomp913 (Mar 7, 2014)

tomp913 said:


> I found the same problem when making a ZCI for a full thickness blade - the solution was to use the outer blade from my dado set, works perfectly so I use it for all blades now. The secret is to only raise the dado blade until it just starts to break through the upper surface - this will give enough clearance on my Unisaw to allow cutting the final slot with the 10" blade being used.
> 
> Another trick that I read somewhere (but didn't make a copy of the article, just have remembered it over the years) is for adding the end slot for the splitter/riving knife. With another insert in the saw and the blade raised, rotate the new ZCI end for end so that it's in the correct position and drop it over the blade. Move the fence so that it's tight against the edge of the ZCi and lock the fence in place. Take the ZCI off the blade, flip it back over so that it's "upright", turn on the saw and cut the slot for the splitter - it will be exactly in line with the saw blade. A little easier than cutting it on the router table.


And it goes without saying that the saw should be OFF while you're setting the fence. Kinda obvious, but it doesn't hurt to point it out.


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## Stick486 (Jan 4, 2013)

qulevrius said:


> Update: the plastic insert isn’t done yet, but in the meantime
> 
> 1... I took DaninVan’s advice and made the essential inserts out of a 1/2” MDF.
> 
> ...


1... W/ the rabbet you cut in that MDF you compromised it's strength..
instead of a rabbet bore tab pockets w/ a fostner bit..

2... skip the polycarbonate.. it's nick insensitive and the edges need additional tooling and sealing..
also when it dries out it becomes brittle..
spawling can be an issue..
go to a dollar store and buy a UHMW cutting board for a dollar and use that..
it'll be about as bullet proof as you can get..
*TIP:*
use negative rake tooling on the UHMW

3... play it smart and use a roll pin...


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## qulevrius (Mar 18, 2019)

Yet another idea on how to make the inserts:







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