Zero clearence insert question

[Greg McCallister]

Ok,
This might be a silly question but I noticed that most if not all zero-clearence table saw blade inserts do not seem to have any screw or clip that holds it in the slot. Are they actually fastened somehow?
If not has anyone had one pop up?
If using a splitter does that not also cause it to pop-up or am I totally wrong on this?

[Joe Chritz]

Mine isn't and it has never popped up at all. You need to be careful making the original kerf but after that it is all good to go.

There is a tab in the back but it doesn't actually hook on anything although it might keep it in if it snagged somehow.

Joe

[Rod Sheridan]

Hi Greg, I simply duplicated the throat plate that came with my saw (General 650) out of HDPE.

The original throat plate has a tab that fits under the table at the trailing end, and four set screws that level the plate in the table top.

That's what I did when I made zero clearance inserts with the exception of using a 3mm roll pin instead of a tab.

I make a few at a time by roughing them out on the bandsaw, and then trimming them with a cutter in the shaper, using the original throat plate as the template.

Regards, Rod.

[Mark Engel]

The purchased zci that I have used for years on my Griz has a roll pin in the trailng edge to keep the back from popping up. Other than that, it is just a friction fit, with four raised areas around the outside edge to snug it up.

I used that zci as a template to make several more out of plywood. I also inserted a finish nail in the trailing edge like the original had. I have never had a 'pop out' problem with the purchased zci or with any of the ones I made myself.

[Eric Haycraft]

Mine came with a roll pin also. It is a really good idea to have that pin in there so if you get one that doesn't include the pin, install one. You could probably get by with a small screw instead of the pin, but it really needs to be present. The pin needs to be at the rear of the plate (where the blade is spinning up and could cause it to raise). Nothing needs to be on the front since that is a downward motion of the blade.

[Chris Padilla]

You can put a smaller washer instead of a roll pin or screw, too.

[D.McDonnel "Mac"]

I have made several "zci" and, like Ron, made mine with the four leveling screws (allen head set screws). The trailing edge got a washer screwed to it to give it a "no lift" feature. However I also added two set screws into one side of the zci to adjust for a snug fit. Just seemed like the right thing to do to keep the insert motionless.

Mac

[Lee Schierer]

On my saw, a Craftsman 10", the OEM throat plates have a spring clip to hold down the back. When I made ZCI inserts I found that they really didn't need the clip in the back. The screw in the front holds them down just fine except for the initial cut up through the insert.

[Greg McCallister]

Thanks everyone for the replies.
I have not made one yet but plan to this weekend.
I have an older Craftsmans saw and with kickback and all the thought of a piece of wood being surrounded by a spinning blade without something holding it down just seemed dangerous.
The pin makes complete sense with the forward motion of the blade.
Do any of you drill a hole for a finger insert for quick removal of the insert for blade changing?

[Mark Engel]

I did not drill a finger hole in any of the inserts I made. Just push down on the back end and the front end pops up enough to get a finger hold.

[Eric Haycraft]

I am a hole driller

[glenn bradley]

My original had a pin to keep the rear down and screwed down in front. My ZCI's have this as well. I use a cutoff 8 penny nail for the pin and the screw is just counter-bored like the original (you can see this on the front left area of the ZCI in the pic).

Trusting gravity . . . well, some folks don't use their bit guards on their router tables either; till something happens. My philosophy is that if I am doing something inherently unsafe and nothing has gone wrong yet, I'm just that much closer to it being my turn and I'd better fix it.

P.s. I also duplicate the finger hole of the original.

http://www.sawmillcreek.org/attachment.php?attachmentid=69206&d=1186000086

If you're making one, make a half a dozen. Mine are specific per blade; I didn't want a sorta-zero clearance insert, I wanted a zero-zero clearance insert. I groove the bottom to allow the plate to be in place while the blade is raised as opposed to clamping it on top of the original and getting sorta close.

82338

Even if it is just pretty close you will still get the safety benefit of stopping little pieces from dropping into the throat or thin pieces from doing the same. Your tearout reduction won't be as good but you could make some specific for that and one or two for just general use.

[Paul Girouard]

No hole , I do insert a small finish nail the little 606N Blum screws are levelers.

Any added hole will reduce dust pick up and allow dust to come out of the whole if no dust collection system is used.

http://i21.photobucket.com/albums/b299/PEG688/tablesawinserts.jpg

The one thats wasted out on the underside , far R.hand one was done a specific reason which I don't remember at this time something with a dado head I think. But my point is , most do not have that wasted out area , just the saw blade kerf.

[Cliff Rohrabacher]

It is the force. You must focus and use the force.
Then gravity seems to do the rest. I never had my old wood inserts pop.

[Brian Penning]

On this subject have any SawStop owners made their own insert?

[Eric Haycraft]

I am curious too. I have an XACTA Deluxe on the way and wonder how one would make a ZCI work with a riving knife.