Zero clearance table saw inserts

MM, a lot of woodworkers DO use dado stacks. Just because you don't is no reason to claim a ZCI is not needed. I use them to help chipping, especially on melamine, but with plywoods as well.

Never suggest to not use your throat plate, that could get someone hurt. Can you imagine the damage if you accidently caught the blade and it pulled you down into the throat hole?
Most standard inserts are made for 90 degree cuts and angles, so use the standard one if nothing else.

My Ryobi BT3000 has a sheet metal insert. However, I have heard of one made from a piece of plexiglass of corresponding thickness. Run the blade to the bottom, install the plexiglass and sloooowly raise the blade. However, I would be concerned about generated heat that would melt the plexiglass.

mobley45 said:

LEXAN PLEXIGLASS IS ALWAYS MY CHOICE.

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Aint true without pictures (unless bought).

Pick up a 2x4' sheet of 1/4 inch pvc. and laminate to get your needed thickness if you end up a little proud, run through router for the lip height. you can also heat it and conform to any odd shapes. I haveca early 1970s 9" craftsman TS that won't die, nothing is easy with that saw, but has great power and will run 10" blades.

Horus said:

Pick up a 2x4' sheet of 1/4 inch pvc. and laminate to get your needed thickness if you end up a little proud, run through router for the lip height. you can also heat it and conform to any odd shapes. I haveca early 1970s 9" craftsman TS that won't die, nothing is easy with that saw, but has great power and will run 10" blades.

Click to expand...

Aint true without pictures.

I made some ZCI inserts for my saw. I got one of those plastic cutting boards (phenolic I think) and cut them to fit the saw throat. I put some leveling screws in it to level them out to the saw table. I machined them for some T slot wood inserts that lined up with the blade, so they can be replaced if the need arose. I made a couple of extras for the day replacement is required. I made one for the main blade and one for the dado head and I'm happy with the results.

hcbph_1 said:

I made some ZCI inserts for my saw. I got one of those plastic cutting boards (phenolic I think) and cut them to fit the saw throat. I put some leveling screws in it to level them out to the saw table. I machined them for some T slot wood inserts that lined up with the blade, so they can be replaced if the need arose. I made a couple of extras for the day replacement is required. I made one for the main blade and one for the dado head and I'm happy with the results.

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Aint true without pictures.

Jwhiteker said:

Thanks MadMark. Solid advice. I wasn't so much worried about close clearance on the dado insert. I was just not having much luck finding a stock metal insert for this saw, so I figured I'd buy/make a zci and just make it. But I prefer simple. Maybe I can find a dado insert that fits this TS. Thanks.

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i believe making inserts is your best bet. it wll give you some more skills and you can make more than one. some spares is never a bad thing. about 14 years ago i made 10 out of hard maple. one for each blade i use(3) and the rest are just in case, which ive had 2 just in case moments.

If your blade thickness and kerf are the same as your 10" blade you can. Also you can put spacers under it so that it just fits in the saw opening, clamp it in place and raise the blade.

Jwhiteker said:

My Grizzly trunion won't send the blade low enough to clear the new insert. Should I put on a circular saw blade in order to make a cut for this standard 10" blade zci?

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Common issue.
I use a 8" dado blade to cut a 3/8" wide relief slot in the underside, ~0.420 deep into a 0.500" thick insert on Unisaw inserts I make.
Then switch to the blade that will mate to the ZCI, and finish the cut.

TBH - Making ZCI with proper side to side and front to back adjusting screws, plus 4 leveling screws, and the relieved slot (like Leecraft sells); is a lot of work.
Usually make several (3-5 or more) at a time, to reduce the burden of all the setups required for: holes, router template profiling, rounded edges, and finally the slot.

YMMV

diy4mark said:

My question is how do you cut the slot for the riving knife? I managed to get it done; but, yuck, it was tricky.

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Do you have a hand saw? Works fine for me.

JohnDon said:

Do you have a hand saw? Works fine for me.

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Good idea, I’ll give that a try on the next insert.

diy4mark said:

I made mine from some oak I had spare and then slotted some HMW plastic in for the blade (though I do like that idea of using a cheap cutting board). Now I have several spare plastic inserts to use for other blades/angles.
My question is how do you cut the slot for the riving knife? I managed to get it done; but, yuck, it was tricky.
View attachment 3875077

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If you're referring to mine, that's actually a splitter that can raise or lower as needed. Now assuming a riving knife has a slot similar to splitter, here's what I did. First I had cut the blade slot by raising the running blade (with the fence being used as a hold-down) to cut the max blade slot. Now measure the distance between the blade slot and the opening for the splitter/riving knife, mark that on your zci. Put your oem blade insert into the saw, align the fence with the exact edge of your new zci. Raise the blade to max height and slowly cut the splitter slot in the zci up to the line you made.
Swap the inserts, lower the blade and try out your new zci.
Hope that helps.

your blade sits below the tabletop and current insert. double side tape your new insert onto the old one, then clamp or tape down. raise the blade.

mobley45 said:

LEXAN PLEXIGLASS IS ALWAYS MY CHOICE.

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I go an extra step by using 1/4 Lexan then drill/tap holes where it sits on the insert rest for 1/4" set screws so you can fine tuning it's height. I found out that the UHMW inserts can warp over time.

If double sided taping on top of original, ensure that the plates are perfectly aligned. Once the cut is made, the two separated and the new put in place, if not properly aligned the kerf will not line up... defeating the purpose of ZCI as the kerf will need to be recut.
Throat plates do not need to be made out of a big log. I use 6mm MDF and dress it down (to 5mm, sanding/planing... as chiselling is too hard😉😉) once seated, level with the tabletop. Most tablesaws, though I don't know your tolerances, should permit blade lowering just a tad below thinner plates... it's the big thick ones that cause grief. If properly "thinned", there should be no need for leveling (grub crews).

Alternatively, bite the bullet and get a smaller dia. blade... even a second hand will do... match kerfs (or a tad bigger)... just don't come through the last few mm... replace the sub-blade with your preferred and finish raising the blade.