Replies

1. 
   Frozen | Jun 25, 2004 03:53pm | #1

   I'm just going with intuition here, but that sounds scary to me. I'm pretty sure that the instructions coming with the dado set would explicitly tell you not to do this.

   I think the main problem would be that the chippers aren't designed to be strong enough to work on the side cuts of the the dado. In normal use, they only need to shear wood that's been cut off on both sides.  I'm not sure what would happen as they failed.

   If you need to make a cut slightly wider than a single blade, just move the fence and take a second pass.

1. 
   BG | Jun 25, 2004 05:01pm | #3

   Frozen, jackplane,

   Instructions ?  ....and I should have read those ????  lol

   I suspect your intuition is correct...Frozen..

   Do you think that uneven force would cause the blade to be askew...jack

   I cut these with the Incra miter...I can shim that the 1/16 or so I need for a second pass...

   Thanks, guys

   Edited 6/25/2004 10:07 am ET by BG

1. 
   jackplane | Jun 25, 2004 07:39pm | #5

   The uneven force does not cause the blade to be askew. If the blade is askew it WILL cause uneven force. You want the blades, the inside one and the outside one, on the arbor at their proper place. If the kerf is too big, use John W s suggestion; I've done it, it works fine.

       But to cut a dado with only one blade and one chipper will result in poor quality (tearout) cuts on the chipper side. The chippers need only have two teeth because their job is to clean out the cut rather than to cut a clean kerf, as the blade does.

1. 
   BG | Jun 25, 2004 09:03pm | #7

   Jackplane,

   I will try John's suggestion in the future.  Read my note to John...I was getting a bit of tearout as I exited...but not on the chipper side....hmm. 

2. 
   jackplane | Jun 25, 2004 04:18pm | #2

   ditto what frozen said. Plus, it's important in dado setup to balance the weight and position of blades and chippers becauseotherwise uneven forces are transfered to the stock and the user.

3. 
   JohnWW | Jun 25, 2004 06:31pm | #4

   BG,

   I can't say quite why, but it doesn't sound like a good idea to me either, especially since you are having trouble with the cut.  The first risk I can see is that the thin unsupported chipper could get bent and ruined and quite possibly grab the stock in the process.

   A safer alternative would be to use a couple of identical thin kerf blades sandwiched together.  This is a "poor man's dado set" that I've used more than once, sometimes with several blades in the stack, when a real dado set wasn't available or affordable.

   You could use a pair of inexpensive 7 1/4 or 8 inch carbide tipped blades meant primarily for Skilsaws, probably something with around 16 teeth per blade.  The only thing to check is that the teeth of one blade will fit between the teeth of the second blade without interference.  If the resulting kerf is too narrow, you could shim between the blades to get a wider cut.  If you have them, sandwiching the stacked blades between stabilizer discs would probably create a cleaner cut.

   In my experience this set up works as well, and as safely, as a regular dado set, but when using an unproven or unfamiliar technique, please be especially careful.

   Hope this helps, John W.

1. 
   BG | Jun 25, 2004 09:01pm | #6

   JohnW,

   It didn't appear to be a good idea to me either...no submission to FWW for the free set of chisels...lol.  However, I'm cutting spanish cedar and I kinda figured its so soft... 

   What was curious is I was getting a double cut(not sure of proper terminology), that is, an initial cut as I went into the wood and cutting a second time as the wood exited the blade...the second cut gave me a ragged edge.  In te setup I put the large dado blade on the arbor first and the chipper second...the second cut was comming from the large dado blade.....my blades have always been parrallel with the miter before...oh well, not gonna do it again anyway... 

1. 
   JohnWW | Jun 25, 2004 09:48pm | #8

   BG,

   It only takes a very slight misalignment for the trailing edge of the blade to brush the side of the cut and cause tearout.  You could try to realign the blade to the slot, it should be checked once in awhile anyway, but the easier thing to do is back up the cut with a second sacrifice piece that will prevent the tearout in the cedar. 

   Cedar is a brittle wood, and prone to tearing out, so the fault may not be due to the saw blade or the tune of the saw.

   John W.

1. 
   BG | Jun 26, 2004 12:34am | #9

   JohnW,

   As I was reading your comments it occured to me what the problem probably is...the throat plate is not flat....I had a bit of an issue last time I cut box joints with this plate...I will double check everything however.

4. 
   Dave45 | Jun 26, 2004 04:20pm | #10

   My dado set explicitly says NOT to use the set without BOTH outside (full) blades.  If you need a dado that narrow, try making multiple passes over a regular blade with the height set to the depth of your dado.

1. 
   BG | Jun 26, 2004 05:18pm | #11

   Dave,

   That is good to know...thanks

2. 
   duster1 | Jun 27, 2004 08:38am | #12

   All,

   Dado sets produce their milling of the wood by two characteristics, mass and rigidity.  recall how the dado set hums, comes to speed and also comes to a rest a lot slower than a single blade.    Placing two thin kerf blades with shims may work, but the lesser rigidity may still cause you edge problems.   If you have a contractor saw, then get the link belt/pulley upgrade.  The vibration that's eliminated is tremendous.

   duster1