Replies

1. 
   Steinmetz | Jun 15, 2003 04:55am | #1

   Bingo! Doc, make the insert blanks from 3/4" oak.

   Rabbet the perimeter so that it fits snug and level (Hand held router or router table.)

   Place a sacrifical board on top and using two cross cleats ,clamp it down for safety's sake.

    Turn on the TS, and raise the cutter up through the insert and a bit more than required for the dado.

    I made several like that,(Blank) and I mill them as I need them.( Especially good when ripping slender width stuff!)

   
   

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   Edited 6/14/2003 9:56:45 PM ET by steinmetz

2. 
   BG | Jun 15, 2003 04:55am | #2

   Dr. U,

   I swap out the insert when I put on the dado blades.  I have three inserts: zero, about 3/8", about 3/4".  Usually the 3/4" gets chosen with the dado blades 

3. 
   forestgirl | Jun 15, 2003 08:19am | #3

   My first z-c insert was made from plywood.  It'll work fine if you don't have any other stock.  Some people think oak doesn't hold up over the long haul, but I wouldn't have any problem with it.  You can also use MDF.  I have a couple made out of maple. 

   If you have a router and a flush-cut bit you can get a nicely-fitting insert by using that to do your final run around the edges of the insert.  The work put into making the insert is returned many times over by much cleaner dado cuts on your saw.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

4. 
   JeffKurtz | Jun 15, 2003 04:27pm | #4

   Most manufacturers have dado inserts available for their saws.  And yes, you can make one from a zero-clearance insert as well.

   Jeff

5. 
   WorkshopJon | Jun 15, 2003 05:54pm | #5

   Dr,

   Obviously we all here at the forum don't know how many you will need (they are sacrificial). But the easiest way is to simply buy a sheet of 7/16' baltic birch plywood, and rip it down to the appropriate width. Then on your bandsaw (you do have one right?) either one at a time (or stacked and spot glued, my preferred method) cut them all out using the one that came with you saw as a template. Should yield about 70. Should take about 15 minutes and cost ~$20.

   Jon

6. 
   vacabby | Jun 16, 2003 03:38am | #6

   We have many zero clearance plates in the shop for nearly every angle and width possible.    We make up new ones by laminated 1/4" temp. hardboard to the desired thickness, drilling holes for leveling screws and inserting a nail into the back edge to hole the rear of the plate in place.     These are very cheap to make and quick.   We zip them out with a template and a pattern bit in a router.    Just another idea.

   jb

1. 
   KevinLBS | Jun 17, 2003 07:34pm | #7

   Hey JB-

   You mentioned the nail in the back of the insert. Can you (or anyone else) tell me if that nail at the back of the insert goes below the tabletop to hold the insert in place, or is it just a pressure fit to the edge of the top?

   I keep imagining making a zero clearance insert, and then a small splinter falls in between the blade and insert, and the insert comes flying out and nails me in the face...

1. 
   vacabby | Jun 18, 2003 01:13am | #10

   We insert the nail so it will be below the level of the table.   To fit under the cast top.    Once you lower the blade, clamp it in place, and make your initial cut there is really no stress on the insert.   The blade has removed everything that could cause it to flip out of place.   The nail is insurance.   If you change blades, even single blades, the kirf may be different so you may need a new insert.    If you angle the blade, different insert.   Most importantly, don't stand directly in front of that blade, ever.   No matter what the insert.    Any kickback or anything else thrown by the blade will be in the direct line of rotation.    That's not just because they tell you not to stand there.    I've stood there and watched others stand there many times.   As long as the insert is a good fit (no slop) and you raise the blade through it (while clamping it down in place)   you have nothing else for the blade to catch on and anthing that falls between the insert and the blade will be so small that it will have no affect on the stability of that insert.    Hope this helps.

   jb

7. 
   mike4244 | Jun 18, 2003 12:00am | #8

   Make a new insert. All of the previous posts were very informative, I would like to add one suggestion. Make the insert out of solid wood, species makes no difference. Make the insert so it is 1/8" crown in the middle. The insert should have a gradual crown from one end to another. The reason for this is you will get a consistent depth of dado all the way. Without the highspot many times the depth varies because the material is not dead flat as it passes thru the dado head. The high spot makes up for this. The material rides the crown over the dado. Dado's in long boards especially can use this type of insert. I lay the insert on a board and trace it. Then bandsaw the outline. I bandsaw the crown, then plane or sand to final dimension. If the board is thicker than the original insert , rabbet a ledge on perimeter.

   I should have explained at the beginning of the post, the crown is in the long dimension.If your insert is 12" long, the high point is at mid point (6" from one end).

   Mike

1. 
   jimmyk | Jun 18, 2003 01:11am | #9

   Heh?

   Making it a little more complex then necessary don't you think?

1. 
   mike4244 | Jun 18, 2003 04:38pm | #11

   Not at all, have you ever dadoed or rabbeted material then went to glue up and found the pieces don't mate? If there is a small discrepancy in the depth of the dado you will have problems. The insert I described takes me about 10 minutes to make.

   You can get away with a flat insert if the material is flat and short. Most sheet goods are not flat, long boards are rarely flat along the entire length.

   Mike