Zero Clearance Inserts

[Don Abele]

Have finalized my purchase of a new Jet tablesaw and had a question concerning zero clearance inserts.

In the past I made my own out of 3/8" plexi (that was for my old craftsman table-top). I see that they are available in some sort of resin material but also note that most people make theirs.

So what's your opinion - purchase (and from who) or make? And if it's make, then please tell me how you do it (no reason for me to reinvent the wheel). Especially interested in material, a holding pin in the rear?, and level screws.

Thanks in advance for your advice and experience.

Be well,

Doc

[David LaRue]

I have made my own out of variety of materials but all out of wood.

As far as purchase goes I highly recommend the Lee-Craft inserts. They are made out a phenolic material, are real flat. In addition they have relief cutouts on the bottom for the blade, have a roll pin in the front to keep the insert from coming back at you, adjustment screws on the side and for level with the table.

The ones I didn't like were the inserts that were like foam board. They are not very strong, and the hole enlarges very easily on them.

Dave

[Dave Sweeney]

I make my own out of scrap wood. Pretty simple really, I trace the design on the scrap using the insert that came with my saw as a pattern. Cut it out using a band saw and then finish sand with my drill press mounted sander drum. I use mirror clips to hold down the rear of the insert, they work great.

[Jim Becker]

Don, I make mine out of 1/2" MDF...and in batches. I use the original as a pattern, rough them out on the bandsaw and then pattern route them to the exact profile at the router table with a bearing-guided bit. (The OEM insert was used as the original pattern and I now have a "master pattern" sans the slot in the rear in MDF. Once I make these blanks, I chuck a core-box bit in the router table and make a relief cut on the back side in-line with the blade to allow it to slip into the saw with the blade lowered all the way down prior to cutting the kerf. Finally, I line up my TS fence with the insert already in the machine and carefully stop-cut the slot for my splitter in the rear of the insert. I finish with a few coats of wax and install a shortened finish nail in the rear to prevent the insert from climbing up the blade.

The first cut up through the insert to make the kerf should be done with the fence partially covering the insert to insure it doesn't go flying across the room.

[Bruce Page]

Doc, I know this isn’t what you had in mind but I made my plate with replaceable oak inserts based on the one you can find in the catalogs for ~ $100. I really like the design and if I didn’t have some machine shop equipment, I would’ve paid the $100 bucks. It is very easy to slip in a new insert, raise the blade and go!

Just a thought.

[Jim Becker]

Doc, I know this isn’t what you had in mind but I made my plate with replaceable oak inserts based on the one you can find in the catalogs for ~ $100. I really like the design and if I didn’t have some machine shop equipment, I would’ve paid the $100 bucks. It is very easy to slip in a new insert, raise the blade and go!

Just a thought.

I've been thinking about this system for some time now...I really like the concept. Do you think that it could be fashioned from all wood, or do you think that the aluminum is really necessary?

[Don Abele]

Bruce, that looks like a great idea and I'm sure I can get a friend to machine me the aluminum insert. How are the oak pieces held in though? Is this the same type of set-up that I've seen on Norm's TS? Also, you mention finding this commericially in catalogs - who makes it?

Jim, the process you describe is pretty much what I had thought would be the "right" answer. With 1/2" MDF do you ever have any problems with flatness? I'm in Virginia now and the humidity is really bad. My dehumidifier in the shop seems to run continuously. I'd be concerned with the moisture swelling the MDF - maybe use hard wood or every ply?

Thanks for your experience.

Be well,

Doc

[Bruce Page]

I've been thinking about this system for some time now...I really like the concept. Do you think that it could be fashioned from all wood, or do you think that the aluminum is really necessary?

Jim, I’m sure that you could, particularly if you made the plate out of hard maple or some other dense wood that would not expand or contract too much. If you look closely at my second pic you’ll see three small holes, they are 4-40 tapped holes with setscrews to lock the insert in. I added them after I discovered that the inserts that I made in the summer and fit like a glove were too loose in the wintertime. :rolleyes:

I have an autocad drawing of it if you’re interested.

[Bruce Page]

Bruce, that looks like a great idea and I'm sure I can get a friend to machine me the aluminum insert. How are the oak pieces held in though? Is this the same type of set-up that I've seen on Norm's TS? Also, you mention finding this commericially in catalogs - who makes it?


Doc, I think Woodcraft sells them and yes, it’s the same setup that Mr. Norm uses. The inserts are held in place with matching dovetails.

[Jim Becker]

Jim, I’m sure that you could, particularly if you made the plate out of hard maple or some other dense wood that would not expand or contract too much. If you look closely at my second pic you’ll see three small holes, they are 4-40 tapped holes with setscrews to lock the insert in. I added them after I discovered that the inserts that I made in the summer and fit like a glove were too loose in the wintertime.

I have an autocad drawing of it if you’re interested.

I would be interested in playing with the drawings...DXF format would be good as I use DesignCAD. Thanks in advance!

[Jim Becker]

With 1/2" MDF do you ever have any problems with flatness? I'm in Virginia now and the humidity is really bad. My dehumidifier in the shop seems to run continuously. I'd be concerned with the moisture swelling the MDF - maybe use hard wood or every ply?


I've had no problems with the MDF relative to humidity...and that's something we "do" have around here! :D MDF will swell from direct contact with water, but it's pretty stable stuff otherwise. The hardwood willl move more, IMHO.

But there is no reason you can't use another material available to you. Plywood, solid wood...some folks buy inexpensive plastic/HPDE cutting boards and adapt them to the purpose.

[Dick Holt]

A past issue of Woodsmith shows how to make a really neat zero clearance insert. It is similar in principle to the one Bruce made. The insert body is made from UHMW plastic with a slot cut in it with a dovetail bit. Then replacable insert strips are cut from hardboard and slide into the slot. You can cut an insert strip for different sized dados, saw blades, etc., all using the same body. If anyone is interested I will see if I can find the issue number. Next time I need zero clearance inserts, this is what I will make.
Dick

[Bruce Page]

I would be interested in playing with the drawings...DXF format would be good as I use DesignCAD. Thanks in advance!

Jim, I'll send you a DXF tonight / tomorrow. (I might have to work late tonight.) :mad:

[Jim Becker]

Jim, I'll send you a DXF tonight / tomorrow. (I might have to work late tonight.)

No hurry...it's not like I'm in need of something to do!! :D