I'd like input on a zero clearance insert

solid surface coutertop material (ie: corian)works well. Easy on cutting tools and stays constant.

I make them out of plastic cutting boards (polyethylene or HDPE) found at wallyworld or the dollar store for way cheap, particularly if you find them on sale.. you can usually find them just the right thickness and one board will make several inserts.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

I use 1/2” MDF. I fasten mine down. Don’t know if it’s necessary.. I usually make 10 or so at a time while I have everything out. Stash them in the cabinet.

-- "Actions speak louder than words but not nearly as often." - Mark Twain

Most inserts have some sort of tab or pin on the edge furthest from the front which keeps it from lifting and becoming airborne if the back edge of the blade catches it. I think this is an important safety feature that I incorporated in all of my ZCIs.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

I use scraps of 1/2”, prefinished, baltic birch. I cut them to shape and do a bit of sanding to get a good fit (not too tight and not too loose). I don’t bother with leveling screws – if one is a little “off” some sanding or a bit of duct tape brings it to where it needs to be.

After I make the first cut (raising the blade), I bore a largish hole at the back of the kerf. This seems to help get more DC airflow at the rising blade gullets. Not perfect, but it seems to keep some sawdust off of the table.

-- Adversity doesn't build character...................it reveals it.

So, it seems like most any man made material would work well for a zci.

I seems to me that the magnets would hold the zci down, unless you were intentionally trying to dislodge it.

I saw on stumpys website he has holes alongside the blade. I thought of putting a baffel to divert the incoming air (suction from the dust collector) through the gullets between the teeth to help keep the sawdust from blowing back in your face. Maybe in addition to Sawkerfs idea of a hole in the back of the slot?

Thank you all for your ideas.

Don’t use plexiglass. It gets brittle when thin and chips if you drop it. Looks cool when it’s new, but gets scratched up fast. My next batches will be MDF with laminate countertop material. I like the thought of magnets, but mine is thin and uses screws. Post them when youre done. I’d like to see how they turn out.

-- Matt CueBall Rosendaul. I don't think I've ever had a cup of coffee that didn't have cat hair or sawdust in it.

I went to Woodcraft yesterday to get magnets. I arbitrarily decided that 3/8ths would be about right. Of course they were out. So i bought 1/4 and 1/2 inch, 3/8 was a guess anyhow. I won’t get any shop time ‘till wednesday or thursday, so I’ll let you know then how it turns out.

Do your inserts warp with laminate on just one side? Or dosen’t MDF expand that much with humidity?

I’m hoping to find a plastic that power sands well. So I can run it through the drum sander to flush it with the table.

My table saw has the magnets mounted in the recess for the ZCI. So my inserts are held in with magnets. I put t-nuts into the bottom of my ZCI and use little allen set screws to adjust height. The t-nuts are centered on the magnets and even if I raise the ZCI off the magnet a little using one of the leveling screws, it has never moved.

Despite cleaning out the recess whenever I remove a ZCI, every once in a while I need to tweak a leveling screw.

My local woodcraft started carrying phenolic coated plywood. I picked up a half sheet of 1/4” that I am going to use to make a lot of ZCI’s. The first batch will be for different dado sizes. The next set will be for different blades. I will need to cut for the riving knife, which will be tricky.

Can you use a ZCI for angled cuts? I use my standard Insert but get more tear out that I would like on miters

-- http://www.etsy.com/shop/KandJWoodCrafts

Lumberjoe,
I assume you mean by angeled cuts that the sawblade is tilted. You can use a ZCI in this application but you need to cut the slot at the angle of bevel that you want. That is part of the reason that I want magnets to hold the ZCI in place. To make it easy to change. The insert that came with my saw fits so tight you need to get under it an tap it up and out with a hammer.

I like the idea of the phenolic ply except I plan to sand to table height after mounting the magnets. I wonder if I could find emery paper that would fit on my thickness sander to sand the magnets instead of the top surface. I don’t much like the idea of magnetic dust in the sander though.

Did they have the phenolic ply in 1/2” then I could glue the magnets 1/32nd proud to be flat with the table.

I’ve got some scrap 1/2” Glass Epoxy Laminate “G10” sitting in my office at work that I’m gonna WJ cut into ZCI’s.

-- Ryan, FRMR HMM165 - HMX1 01-10

Use a screw at one end and dial in a nice friction fit. Forget the magnets.

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UHMW is too prone to warping and it flexes, making it a poor choice for something as large as a TS insert. Phenolic and birch ply are both better materials IMHO.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

Tenfingers58, That is what I meant. The phenolic plywood is really nice. You can get it in any nominal plywood thickness. My saw actually has leveling screws that I can adjust. I need to figure out a way to put a tab on the back as gfadvm suggests.

My saw also has a magnet in the front already, so I am just going to inset and epoxy a washer in the bottom to make contact with the magnet.

-- http://www.etsy.com/shop/KandJWoodCrafts