Help with Zero Clearance Insert

[Jason Hanko]

I’d really like to make a zero clearance insert for my cheapo Jet contractor table saw, but because of the design of the mounting setup I don’t know if its going to be doable….
As you can see from the pictures, the “mounting tab” that secures the insert comes within ~1/16’’ from the surface of the table. I could easily rout out the bottom of any homemade insert to fit over the area, but Im thinking that would leave the material very thin there…
Almost certainly too thin to make an insert out of wood, but how about phenolic?
As far as Ive been able to tell in my searches there are no aftermarket inserts available for my saw (don't have the model# on hand, can post it later if anyone thinks it would help)
Any ideas?

[Chris Padilla]

It appears to me with some trial and error that you could use the current red metal cover to secure a ZCI. It *might* require grinding or removing some material from the current squarish threaded section of the throat.

I can't tell for sure from the pictures but is there a lip on the left side of the throat? If so, this idea might work.

[glenn bradley]

Boy, that does present a challenge. An alternative would be to lay a piece of thin material over the throat for those ZCI cuts. I use an insert for all cuts but with what looks like a 3/32" plate restriction over the mounting holes, you may want to consider a lay-over (http://www.woodworkingtips.com/etips/etip020419sn.html).

[Doug Shepard]

It doesn't look like the ledge around the opening is any deeper than those tab pieces either. What about using the metal insert to attach a wood one on the open side, maybe 1/2" BB ply routed out on the top RH side to go underneath the metal insert? And the ply bottom routed on the LH side to sit on the ledge? Then a few more holes drilled and countersunk through the metal one to attach the ply?

[Norman Pyles]

It doesn't look like the ledge around the opening is any deeper than those tab pieces either. What about using the metal insert to attach a wood one on the open side, maybe 1/2" BB ply routed out on the top RH side to go underneath the metal insert? And the ply bottom routed on the LH side to sit on the ledge? Then a few more holes drilled and countersunk through the metal one to attach the ply?
Was gonna post the same answer, but Doug beat me to it. :)

[Ray Schafer]

This doesn't solve your problem, but could help in the short term.

You can use some thin masonite to cover your table and use that for your zero clearance. This won't work in cases where you need to use the miter gauge, but it helps in many cases.

[Walt Caza]

Hi Jason,
Yep, your situation looks a little tricky.
The accomplished jig-meister Glenn B. has already suggested a ZC overlay.
They are useful in many situations, and quick when they can be used.

Here is a link to one I used recently - with pics (link):
http://www.sawmillcreek.org/showthread.php?t=89329

Quick and dirty, but effective...
good luck with it,
Walt

[Jason Hanko]

Thanks for the input guys! This is why I love this forum.

Glen/Walt: This was actually my original line of thinking - altho I was thinking of taking it a step farther and creating a whole new table surface by laying a piece of 3/4 ply over the top of the existing table. The existing table isnt exactly flat anyways (cheap saw) and I could easily rout new miter slots with a 3/8 straight and my T-slot bit.

Chris/Doug: I like this idea best of all, but it also seems like it will be the hardest to pull off. There is a small (emphasis on the small) ledge on the left side of the throat. Has the same issue though in that the ledge is only 3/32 from the top of the table and Im worried that that a routed ledge on the new insert that thin would simply snap off.
Ive thought about grinding it down, but I dont really have the tools to do so, and dont trust in my ability to do so well enough to end up with a flat, level surface afterwards.
How would you recommend countersinking into the existing metal insert? Id have to punch the metal down somehow to make a divit for the screwhead...

[Brian Tax]

I don't have any info on the topic, but I love your signature, I am dealing with someone at work right now that it is perfect for.

[Bill White]

your definition of incompetence is PRICELESS.
Bill

[Chris Padilla]

Chris/Doug: I like this idea best of all, but it also seems like it will be the hardest to pull off. There is a small (emphasis on the small) ledge on the left side of the throat. Has the same issue though in that the ledge is only 3/32 from the top of the table and Im worried that that a routed ledge on the new insert that thin would simply snap off.
Ive thought about grinding it down, but I dont really have the tools to do so, and dont trust in my ability to do so well enough to end up with a flat, level surface afterwards.
How would you recommend countersinking into the existing metal insert? Id have to punch the metal down somehow to make a divit for the screwhead...

Just because the ZCI will be thin here doesn't mean it can't be strong. I would suggest first mocking up something with cheap plywood or MDF and then consider moving to hardwood for the final ZCI once you have the design nailed down.

A Dremel or Rotozip isn't too much money and very handy for a lot of things so consider picking one up.

How thin is the red metal piece?

[Doug Shepard]

...There is a small (emphasis on the small) ledge on the left side of the throat. Has the same issue though in that the ledge is only 3/32 from the top of the table and Im worried that that a routed ledge on the new insert that thin would simply snap off.
Like Chris, I dont think this is all that big a deal. The support would be on the RH side screwed to the metal insert more than really relying on a thin wood tongue.

How would you recommend countersinking into the existing metal insert? Id have to punch the metal down somehow to make a divit for the screwhead...
Real metal workers here are sure to flame me, but I've used regular countersink bits for wood for the occasional holes in metal. You could probably get something cheap at Harbor Freight that would work well enough for the 3-4 holes you'd need.



Another thought is to get another metal insert and cut it, or some metal of the same thickness and make a piece to sit on the LH side with a central wood portion between them and screwed to both metal pieces. You'd only have to deal with mortising out the same depth setting on the top face rather than also for the bottom rabbet as well. Chris' hardwood suggestion has another plus. You could cut the top mortise to leave the face 1-2 thou proud of the table top and use a block plane to level it dead flat with the top. Just go slow from both sides and be careful to stop before you hit metal.

[Jason Hanko]

How thin is the red metal piece? Without measuring Id say about 3/32... pretty thin - it bends easily in the middle while bolted to the table.

your definition of incompetence is PRICELESS.
Bill Thanks, but I can't take credit: http://despair.com/viewall.html (http://despair.com/viewall.html)

[Matthias Imhof]

I actually spend last weekend to build an insert for this very same saw. The approach I took was to build a MDF gasket with an outside size of 11x3 and screwed it beneath the metal brackets. Doing this, I have now a ledge 1/2" beneath the table surface onto which I lay the insert.

The insert itself is 10 1/2 by 2 1/2, made of 1/2" MDF with a slight bevel on the left side. In the middle of the right side, I routed a narrow rabbit leaving 1/8" MDF left for the little metal brackets. Top right and bottom right, I routed away a square inch leaving 1/8" MDF for the metal brackets. Two screws attach the insert firmly to the gasket.

Matthias

[Jason Hanko]

I actually spend last weekend to build an insert for this very same saw. The approach I took was to build a MDF gasket with an outside size of 11x3 and screwed it beneath the metal brackets. Doing this, I have now a ledge 1/2" beneath the table surface onto which I lay the insert.

The insert itself is 10 1/2 by 2 1/2, made of 1/2" MDF with a slight bevel on the left side. In the middle of the right side, I routed a narrow rabbit leaving 1/8" MDF left for the little metal brackets. Top right and bottom right, I routed away a square inch leaving 1/8" MDF for the metal brackets. Two screws attach the insert firmly to the gasket.

Matthias
Pictures?? :D:D:D

[Johnny Kleso]

I have a HF Contractor saw and made several inserts already..

I have used 1/8" hardboard and 1/8" plastic both flex in the center and is a pain it small parts..

What I did was glue a second sheet to the bottom with it roughed out to clear the lip..

You could also glue of screw some stiffening ribs which would make it plenty stiff

PS:
both of these material are .100 thick not 1/8" (.125) and closer to 3/32 (.093) than 1/8"

[Charles Seehuetter Panama City]

I may be way off base here as I haven't actually tried this but how about taking your insert to a sheet metal shop and have them cut one out of aluminum the same thickness are yours and wide enough to cover the opening in the saw. Counter sink the holes where the screws attach it. Throw an old carbide blade on the saw backwards. (Clean all the sawdust out) Screw on the new insert and slowly raise the blade through the aluminum. It'll make a lot of noise but should cut through it. I've used backwards blades on circular saws many times to cut aluminum and steel roofing and it works like a charm.

Chuck

[Lee Schierer]

I don't think any one has mentioned this idea yet. Get a similar thickness piece of sheet metal to your existing insert or another insert. Trim it back so there is a wider opening for the area where the saw blade will come up through. Cut some wood to fit under the metal insert and rabbet it so that the top is flush to the top of the metal insert. This wood should totally fill the open area over the blade. Attach this wood to the under side of the trimmed down metal insert with screws. The piece of hardwood can be 1/2" or thicker and basically hang down under the metal insert. It will also act to stiffen the metal insert.

Depending upon how far below the table surface you blade will lower, you may need to make a wood adapter that would be above the table surface and hold the wood part of your ZCI to make the "cut through" for the ZCI.