# Zero Clearance inserts



## gpeck (Nov 24, 2010)

I see mention of zero clearance inserts for table saws. I believe that defines minimum clearance on each side of the saw blade verses a gap that the factory insert has. I would guess that the blade would have to be set at 90 degrees to the table for this to work. What is the advantage to this? Is it somehow safer?
Thanks


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## woodnthings (Jan 24, 2009)

*2 reasons*

It makes a cleaner cut with less tear out AND it prevents thin slivers of ripped material from getting jammed between the blade and the insert. There is a natural human tendency to pull them out before the blade fully stops, usually resulting in a kickback or worse yet, injury. :thumbdown:

Ninety degrees is the only way for vertical cuts, but others have tilted the blade for specific angles as well. Raising the blade into the work slowly and having the insert held down firmly by clamps or the fence are requirements. Depending on the insert thickness, a 10" blade may still be too large and you may have to use a 7 1/4" blade from a circular saw to start the kerf.


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## gpeck (Nov 24, 2010)

I made a zero clearance insert for my saw. It came out real nice. I have not yet cut the blade slot. What is the best way to do that and how wide should the slot be? I was going to block the insert in with a couple heavy magnets and raise the running saw blade into the insert. 
Thanks


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## cabinetman (Jul 5, 2007)

gpeck said:


> I made a zero clearance insert for my saw. It came out real nice. I have not yet cut the blade slot. What is the best way to do that and how wide should the slot be? I was going to block the insert in with a couple heavy magnets and raise the running saw blade into the insert.
> Thanks


A zero clearance insert (sometimes referred to as a ZCI) offers minimal clearance around the blade while cutting and provides support for the piece being cut. It provides for a safer operation and a cleaner cut. It does help prevent debris from being jammed between the blade and the insert. Only an absolute fool will stick his fingers there to clear it out while the blade is running. Not a common "accident", thank goodness.

While you have the one you made (call it a template, or sample), make a few. Cut your stock close to the line, and use either a band saw, scroll saw, or a jig saw, and cut close to the line. Then, double side tape it or hot glue it to your template, and rout the new one with a flush trim bit with a bearing. 

Place the template in the opening, and if it needs leveling, you could insert small screws in the bottom side to raise and lower it. With many saws, ½" material, like plywood works very well. Your particular saw may require a thinner, or thicker piece.

Crank the blade all the way down and place the template in the opening. Your blade may not retract enough to clear the bottom surface. If that's the case use a blade from a hand held circular saw (7¼") to start the kerf. If you are using primarily 10" blades with an eight inch kerf, find a circular saw blade with the same kerf. 

You can move the fence over the top of the template (but make sure the blade won't hit it when raised). Or, you can clamp a board or plywood to the table to hold down the template. Turn on the saw, and slowly raise the blade through the template, and raise it all the way up. You're done.


















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## woodnthings (Jan 24, 2009)

*how to make you own*


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## gpeck (Nov 24, 2010)

Very neat. The fence will work great for holding the insert.
thanks


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## Oakwerks (Mar 24, 2013)

A zero clearance insert also keeps large shavings from dropping thru the slot and getting into the dust collector Impeller, if you're using one....


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## gpeck (Nov 24, 2010)

That is a huge problem for me, small slivers cause big problems.


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## bladeburner (Jun 8, 2013)

I'm with Cabinetman. My shop environment is not the same as Mr. Wandel's, so my one attempt at a piston fit insert failed when it swelled into a hump and I had to chisel it out. Now I make 3-4 at a time using an original copy double taped to 1/2" MDF. MDF holds setscrews well without tapping threads and I paint them all RED, all over. For the initial cut, I use an outside blade from a dado set. And since I'm getting forgetful, I make notes to myself like this...


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## ryan50hrl (Jun 30, 2012)

gpeck said:


> That is a huge problem for me, small slivers cause big problems.


So...can you explain this? Should I be more careful about what gets into my dc?


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## Dave Paine (May 30, 2012)

ryan50hrl said:


> So...can you explain this? Should I be more careful about what gets into my dc?


I am not sure why slivers are a problem for gpeck in the dust collector. Not a problem in mine.

There was a thread a few weeks ago about a dust collector inlet getting blocked up. The inlet had a metal cross brace, likely to prevent fingers getting into the unit, but the metal was easily catching shavings. The poster was asking if it was a problem to cut out the bracing.

I have a Thien baffle inside the dust collector. I rarely have big pieces of wood going to the dust collector. The blower design has at least 1in space between the housing and the tip of the blower fins. I think the intent is for the space to carry the air and debris without touching the fins.

I rarely hear anything hit the fins. They are beefy and designed to withstand impact.

So far I have not needed to be concerned at the particles picked up by the dust collector. These days the larger particles are from my lathe than the table saw.

I do use a zero clearance insert, except when I use the dado blade, or need to tilt the blade to make a bevel cut.


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## ryan50hrl (Jun 30, 2012)

That was my assumption as well....every now and then ill hear a ping as something hits the fan, but it's never been a problem that I was aware of.


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## gpeck (Nov 24, 2010)

I rip a lot of White cedar. I am left with 1/16 inch thick strips that sneak past the saw blade and eventually plug the suction port. 
The zero clearance insert should help a lot.


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## woodnthings (Jan 24, 2009)

*the ping is....*



ryan50hrl said:


> That was my assumption as well....every now and then ill hear* a ping as something hits the fan*, but it's never been a problem that I was aware of.



That's the sh*t hitting the fan. Don't worry it happens all the time in my shop. There will probably be a nationwide occurance soon.... :blink:


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## cabinetman (Jul 5, 2007)

woodnthings said:


> That's the sh*t hitting the fan. Don't worry it happens all the time in my shop. There will probably be a nationwide occurance soon.... :blink:


It happens on forums all the time.:laughing:


















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## Mark G (Dec 26, 2011)

I've needed a zero clearance insert for my Craftsman Model 137.218300 since, well, day 1. I just didn't know it until I joined this board. But then I could not find or easily make a template because there are so many challenges. The insert can only be 3/16th inch thick. I can't simply route a border rabbet to allow thicker material because there is a support bar in the way, too, that runs the entire length of the plate opening. Template makers don't make one for this model.

But yesterday I got a GRR Ripper, and to make good use of its ability to cut narrow rips I have to get off the stick so to speak and fashion a ZCI.

Well, lookie what I found. 

http://www.instructables.com/id/Easy-zero-clearance-throatplate-for-any-table-saw/#step1

It looks like a clever solution. What kind of wood do y'all think I should use for the filler strip in step 2? This strip will be sanded down to be flush with the insert surface.


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## Brian T. (Dec 19, 2012)

What have you got for woods? I'd use birch because I have lots of it. I can't imagine that there's going to be a whole lot of down force on it. Oak, walnut, beech, maple, even aspen or basswood.


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## woodnthings (Jan 24, 2009)

*I posted this in 2009*

http://www.woodworkingtalk.com/f27/make-zero-clearance-throat-plate-insert-10147/

another version for the thicker plates:
http://www.woodworkingtalk.com/f27/zero-clearance-insert-40486/


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## Mark G (Dec 26, 2011)

woodnthings said:


> http://www.woodworkingtalk.com/f27/make-zero-clearance-throat-plate-insert-10147/
> 
> another version for the thicker plates:
> http://www.woodworkingtalk.com/f27/zero-clearance-insert-40486/


Nice. In the immortal words of Jed Clampett, "Wheeee doggie!" I guess there is nothing really new under the sun.

The original insert has a particularly weak feature on this saw model. On the back end, the waste side and main side of the metal insert do not rejoin. The opening runs clear through, making the overall insert more like a metal fork than a rectangle. I am very happy to be bridging that gap on the underside.

And I'm using some scrap cherry for the topside insert.

The 10" saw blade will not detract far enough to allow the uncut ZCI template to rest flat. I'm nervous about attempting to plunge it, so I will use the 7 1/4" blade from my circular saw to get started.


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## Mark G (Dec 26, 2011)

Well, this has been a real PITA. I've tried a few things that haven't worked out. The problem is that on my particular jobsite table saw there is a support bar running the full depth of the table, parallel to the saw blade and, it is right underneath the edge of the orginal insert opening. And it is also very close to the plate's bottom. This makes it darn near impossible to glue something underneath because there is too little surface area for it to attach on the bar-side of the insert opening. 

See the last picture in this thread: http://lumberjocks.com/projects/12778 

That's the kind of saw I have. You can see the support bar in the last picture.

So yesterday I bought some 1/2" MDF, cut it to size, rounded the three corners (one corner is square for some reason), and routed a cove channel that perfectly accomdates the top of the bar.

Now I need to route 4 recessed areas on the underside to accomodate the 4 adjustment screws and their platform thingies. You can barely see two of the platform thingies in the last picture - one in the near left of the table opening and one in the far right part of the opening.

Don't you think this is a great excuse for buying a small one-hand router to compliment my larger Porter Cable router? Don't you think my wife would agree?

I misread the thread and went out and bought 1/2" MDF instead of 1/4". But I like the 1/2" for its strength. I also don't like that the guy in the lumberjocks thread used cardboard instead of the adjustment screws.


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