Do most / all of you make your own? I ordered two in MDF, wanting to put my time into other stuff. The first one cracked; you can see what the blade did to this pair of sub-1/8" heartpine slats. The crack on the outside flexed the insert, pinched the inside board. All is good, no danger, just a moment of confusion.

 

• Are flexing inserts a problem or do they usually not flex?

 

• Can you over-stress an insert?

 

• Are most inserts made of solid wood? My two are MDF, the seller CNCs hundreds per week, thinks it was the insert.

 

• Can a sliver of wood caught between the blade and the slot cause the failure I experienced?  Can I glue 1/4" hardwood beneath the insert to beef it up?

 

• Does in insert made from a single piece of wood ever blow apart?

 

Time to man-up and make my own out of hardwood from scratch?  (Rhetorical) There is a way to laminate hardwood two directions - straight + diagonal - and cut the rabbeted edge on a table saw. Guess I could do it.

 

On a good note, I got EIGHT slats from an interesting 9/4 x 9 x 24 scrap, plenty for my headboard now! Wait until you see the figuring. AND got the ebony-violin-fingerboard-turned-lid rabbeted. Cut a good three hours, blew out the dust, cleaned up, and everyone is happy.

 

 

 

 

 

 

 

 

 

I make my own, usually from oak for no particular reason other than I have lots of scraps. Add set screws for leveling. Usually cut a bunch of blanks all at once. Have them made for the most often used angles, for me. 0°, 45°, 22.5° and 7°. Never had one break, yet.

I made one out of UHMW plastic.  Been a few years and no signs of needing to replace it.  Works well.

I'm a big fan of them. In the past I've made them out of a hardwood (species unknown), and used them for quite a while before I sold that saw. Never had one blow apart, and I'm not sure about the over stressing part. I suspect that most folks now use MDF to make theirs, a lot of inserts are 1/2" thick and MDF is prety good for being that thickness....plywood not so much. What will happen to them over time is the opeing will enlarge every so slightly, and you can get the thinner sliver caught between the insert and the blade. Also the damage I see near the end of the opening (in your pic) is fairly common. I think the swarf circulating with the blade is a little bit  abrasive...just a guess. What I would suggest is to make a hardwood one and try it out, it will be more durable than MDF.

5 minutes ago, Fred W. Hargis Jr said:

the swarf circulating with the blade

Time to hit the auto parts store.  ∆ C.I. deck begging for wax, mitre track & gauge especially. 

 

• Do you also wax the sides of your blade?

 

Attached: A picture of Mason Sailor's black walnut zero clearance insert for inspiration. 

 

On a good note, the preliminary layout of a decorative heart pine wall-mount headboard is coming together.

 

black walnut zero clearance insert credit masonsailor 1364 × 628 pixels

Some of your old growth pine would make a good ZCI. I'm sure that stuff is pretty stable.

11 hours ago, lew said:

I make my own, usually from oak for no particular reason other than I have lots of scraps. Add set screws for leveling. Usually cut a bunch of blanks all at once. Have them made for the most often used angles, for me. 0°, 45°, 22.5° and 7°. Never had one break, yet.

 

Lew, how do you do a zero clearance for a specific angle?

1 hour ago, Woodman said:

 

• Do you also wax the sides of your blade?

 

 

 

 I don't, just a word of caution....do not use car wax on your cast iron. Car waxes generally have a silicon component, and it can rub off on your wood. Once it does finishes won't stick. Use a paste floor wax, like Johnson's wax, Triwax, ort one of the other dozen or so brands. They are usually found with the floor cleaning products at the box stores, discount stores, etc.

30 minutes ago, Fred W. Hargis Jr said:

 I don't, just a word of caution....do not use car wax on your cast iron. Car waxes generally have a silicon component, and it can rub off on your wood. Once it does finishes won't stick. 

Doggonnit! I didn't think of that. Already used car wax on saw and planer tables. Guess I'll have to give my boards an acetone bath before the finish. But, nothings been sanded yet. Do you think sanding will mitigate the effects? 

I do have a new can of JPW. Time to re wax.

2 hours ago, Woodman said:

Time to hit the auto parts store.  ∆ C.I. deck begging for wax, mitre track & gauge especially. 

 

• Do you also wax the sides of your blade?

 

42 minutes ago, Fred W. Hargis Jr said:

 I don't, just a word of caution....do not use car wax on your cast iron. Car waxes generally have a silicon component, and it can rub off on your wood. Once it does finishes won't stick. Use a paste floor wax, like Johnson's wax, Triwax, ort one of the other dozen or so brands. They are usually found with the floor cleaning products at the box stores, discount stores, etc.

 

3 minutes ago, Gene Howe said:

Doggonnit! I didn't think of that. Already used car wax on saw and planer tables. Guess I'll have to give my boards an acetone bath before the finish. But, nothings been sanded yet. Do you think sanding will mitigate the effects? 

I do have a new can of JPW. Time to re wax.

Many of the newer automotive waxes no longer have silicone substances; can damage clear coat finishes. Most of the good, higher end all contain carnauba which should be OK. That said, I generally always use Johnson Paste wax.

 

Interesting side note, I've been buying Johnsons for years at our local Home Depot. Apparently HD no longer carries it in their product offerings. Fortunately, our local ACE Hardware stocks it. A little more expensive than HD, but that could just be the whole supply chain, transportation cost issue.

10 hours ago, HandyDan said:

I made one out of UHMW plastic.  Been a few years and no signs of needing to replace it.  Works well.

Same here but I purchased pre-made several years ago at one of the Woodworking Shows. Looks like they've gone up in price a little.

Zero Clearance Inserts

Edited May 11, 20224 yr by Grandpadave52

6 minutes ago, Grandpadave52 said:

Looks like they gone up in price a little.

 

Still not a bad price.  I got the materials for mine free but considering the cost of materials and the time involved, buying one looks like a bargain.

Like others I make my own. Not had any issues and I do have set screws made into bottom.  Used a piece of solid wood flooring I got out of tear down of older home.

2 minutes ago, HandyDan said:

 

Still not a bad price.  I got the materials for mine free but considering the cost of materials and the time involved, buying one looks like a bargain.

No not really...shipping drives it up though, although PT offers free shipping from time-to-time. Mine were a perfect fit for the old Craftsman. Still working perfectly.

I’ve always made my own out of whatever is around. Like Gunny I don’t use set screws. As far as ones for different angles, when I meed one it’s usually time for a new one anyway. Keep in mind by turning them around you get two cuts in each one. 
Paul

2 hours ago, Gene Howe said:

Doggonnit! I didn't think of that. Already used car wax on saw and planer tables. Guess I'll have to give my boards an acetone bath before the finish. But, nothings been sanded yet. Do you think sanding will mitigate the effects? 

I do have a new can of JPW. Time to re wax.

Might be a question for Keith, I've never tried since I've never used car wax. I have had silicone contamination on other stuff, and it's a bee-yitch to remove,But check your wax, maybe it doesn't have silicon like Dave said.

4 hours ago, Cal said:

 

Lew, how do you do a zero clearance for a specific angle?

I use a wixey angle cube and set the blade angle. Lower the blade as far as it will go. Set in the uncut insert. Slowly raise the blade. I have some lead weights I set on the insert while raising the blade to keep it in place.

Set the second insert. ZERO sanding. One hole DEAD ON, the other .5mm south. A little counterbore to the north hole, and little drill bit to the other, and perfect fit. Three projects plus assorted 'laundry' tomorrow.

 

It is different with each saw. My Grizzley has small stubs that the insert sits on. If your edge only allows less than 1/8 you can reinforce the rest of the insert. With Griz the blade does not drop down far enough to use 3/4 unless you first relieve the underside with router or carve. I then put insert in place with 2x clamped on top and raise the blade. By the way Don't think MDF is appropriate in this use.

4 hours ago, Gerald said:

Don't think MDF is appropriate in this use.

Thank you, Gerald. I’m thinking the same thing. The insert might want to be of the same strength as what is being run through the saw. 
 

MDF works for many people, but there’s a percentage pushing their saw a little harder. 
 

I’m studying the spare and will likely glue a few strips of harder woods together, like Paul’s black walnut. Use the table saw to put a rabbet around its edge.