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Zero Clearance Insert

3K views 14 replies 13 participants last post by  Varcuri 
#1 · (Edited by Moderator)
I purchased a pre-cut phenolic insert for my Craftsman table saw from Rockler. I need to raise the blade to make the initial cut-thru but the blade doesn't retract into the saw table enough to allow the insert to fully sit down yet.

I'm thinking about installing one blade from my Freud Super Dado set just to make the initial cut and then reinstalling my 10" blade for the remainder of the pass-thru. Do you see any problem with this approach?

I've read a few articles that talk about clamping a piece of wood to the table top, etc…but just using a smaller blade seems to be so much simplier. I believe they are all the same standard kerf (1/8") but I haven't measured them yet.

Am I missing something?
 
#2 ·
That's odd your blade won't retract all the way… I am not familiar with Craftsman saws, but could there possibly be something binding the retraction screw (sawdust), so it won't go all the way down? I had that problem with my Ridgid with the tilt screw. Had to get under the tabletop and clean off the threaded rod.

Just a thought since I had that problem.
 
#3 ·
the blade on my Craftsman contractors saw doesn't retract very far either…. The ZCI is a lot thicker than the metal insert, and I've heard other reports that they don't clear as well…

I think your plan to use the 8" blade from you dado stack is a good one.
 
#4 ·
As long as the dado blade has the same kerf as the blade you plan on using it should work. If the kerf is bigger you'll end up with some portion of the insert that is positive clearance rather than zero clearance, and if it is narrower you won't cut through enough to get your main blade in the opening.

I would still plan on clamping the insert down when you cut the kerf. If you just set it on the saw and raise the blade, there's a really good chance the insert will lift up and be thrown with significant force. Don't get hurt!
 
#5 ·
Measure how far below the table surface the 10" blade sits. I would then put in the dado blade and raise it to just above that spot. Then lower it all the way down counting the number of times I turned the crank. After clamping a board down to hold the insert, turn on the saw, raise the dado blade the same number of turns to cut the bottom of the insert to make room for the 10" blade. Install the 10" blade you will be using with the insert, reclamp the insert and cut through.
 
#6 ·
I would recommend using a 7 1/4 inch blade with the same kerf size. After the initial cut, replace with your blade and use a piece of scrap clamped to the front and back of the saw (runs over the insert) to hold down the insert while raising the blade.
 
#7 ·
One trick I used when I ran into the same situation (wanted a ZCI for a thin kerf blade) was to use double-sided tape to tape the new insert on top of the existing (tape ensures that when you have them aligned exactly it stays that way). Install the new double plate onto the saw. Now clamp a board across the entire mess and then slowly raise the blade through the entire contraption. Sounds kind of awkward but I got good results.
 
#9 ·
I never saw a saw that the blade didn't retract all the way below the table. This is my safety position when the shop is unattended. Then, even if some yay-hoo starts pressing buttons, noone gets hurt.

Perhaps the gears are packed with sawdust underneath there?
Some obstruction likely is keeping from retracting all the way.
 
#10 ·
Most 10" table saws, won't retract the blade far enough under the table. When I make my own inserts, I usually run a dado the length of the insert leaving just under 1/4" thickness. then it will sit flush without the blade touching so you can raise it through without any problems
 
#12 ·
The 113.zzzzzz series of Craftsman contractor saws retract the blade to a point even with the table top. Your idea to use a dado blade is a good way to go. It doesn't matter if the starter hole you make is a bit wider than the saw blade. The "non tear out" advantage of the ZCI takes place at the front of the blade, not the middle. I clamp a board front and back…can't be too careful.

My Grizzly 1023SL does not lower enough to start a cut in an insert and IIRC, Unisaws don't either.
 
#14 ·
+1 on DeltaRich's idea. Also, I thought most people just slid their fence over the edge of the insert while raising the blade. I've read that tip about a dozen times in magazines. Unless your blade is extremely dull, it doesn't take much to hold the insert down.
 
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