Replies

1. 
   philip_r | Feb 20, 2009 01:43am | #1

   Dado set in a tablesaw or a router/router bit combo are the two ways I'd go.  I never feel safe with a circular saw.

   If neither are available:

   1. Count to 10 (use your fingers)
   2. Cut with a circular saw
   3. Count to 10 (checking your fingers)
2. 
   WillGeorge | Feb 20, 2009 02:39am | #2

   OK, a safety violation some will say.. I sort of agree.

   I did that building a very large outdoor deck.  Three 'contractors blades' stacked together as I recall. Worked great. I did check often to see if anything something loosened up. Nothing ever moved.

   I would suggest that you DO NOT use carbide tipped blades. Carbide shatters and you may loose a eye or two.

   Just me, but I do weird stuff all the time, and have lived a long life...

3. 
   roc | Feb 20, 2009 02:56am | #3

   You could put a spacer between the circular saw and your straight edge. Hold one of those paint barriers with the handle on it and slide the two , saw and barrier, together down the length of the cut.

   http://www.amazon.com/HYDE-45005-PAINT-SHEILD-SIZE/dp/B001NOGI94/ref=sr_1_1?ie=UTF8&s=hiqid=1235087453&sr=1-1

   I haven't tried this. You may need to smooth the metal edges with emery paper.

   I suppose if you did this groove a lot you could get a saw dude to custom grind a wider blade to your spec. Really all it would take is a few teeth bent further out on a noncarbide saw blade.

   No experience here just day dreaming.

   roc

   Give me six hours to chop down a tree and I will spend the first four sharpening the axe. Abraham Lincoln ( 54° shaves )

4. 
   heartwould | Feb 20, 2009 03:02am | #4

   Go with a router if at all possible.  Much easier to control. 

1. 
   hammer1 | Feb 20, 2009 06:53am | #5

   Absolutely!Beat it to fit / Paint it to match

5. 
   forestgirl | Feb 20, 2009 07:09am | #6

   I wonder if a metric router bit would work.  1/8" = 3.18 mm;   1/4" = 6.35 mm

   That gives you 4mm, 5mm and 6mm inbetween the two.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 
   
6. 
   ring | Feb 20, 2009 07:55am | #7

   Yes, I've done it that way on one occasion. I found that the only problematic factor is that the gullets in the blades, being somewhat filled with the teeth of the neighboring blade, don't clear chips nearly as well as you want. The result is that you very easily get burning, and you need to stop often to clean out the blades.

   David Ring

   http://www.touchwood.co.il/?lang=e&id=1

7. 
   philip | Feb 20, 2009 08:23am | #8

   Ed,
   Shallow grooves like that are absolutely very doable and no safety concerns whatsoever- a doddle as they say.I have done it happily on my table saw but prefer the alternative of stacking two or more blades on my shaper.
   What you intend to do in off setting them so that the teeth of one are accommodated in the gullets of the other is correct because then the plates will be in contact before you tighten the arbor nut-i.e no distortion will take place.
   If you needed a wider kerf you have some leeway to exploit due to the width of the carbide teeth compared to the plate so you could use paper spacers.
   What table insert have you got? If you have a sacrificial type and can lower those blades below it then you can raise the blades into it .
   You will need to go carefully at first until you gauge what feed rate to apply.

   Philip Marcou
8. 
   MikeHennessy | Feb 20, 2009 03:21pm | #9

   I'm firmly in the "no problem" camp. I'd do it in a heartbeat. Pretty much a self-made dado stack. Especially since the groove is so shallow -- that should eliminate any problem with ejecting waste from the gullets.

   That said, if you're nervous about it, just use a straightedge guide with a single blade in the saw, run one kerf, add a spacer between the saw and the guide to make up the added width you need, and run it a second time to complete the kerf.

   Mike Hennessy
   Pittsburgh, PA

   Edit: Maybe I'm weird . . . well OK, I AM weird . . . but for me, a CS is far easier to control for a straight cut than a router. The mechanics of the CS blade make it wanna go straight(ish). A router wants to wander, since there are diametrically opposed forces working on either side of the cut. Just try to make a straight cut (sans fence) with a router with a 1/4" bit vs. a CS. For me, anyway, no comparison.

   
   

   ---

   Edited 2/20/2009 7:27 am ET by MikeHennessy

1. 
   EdHarrow | Feb 20, 2009 08:17pm | #10

   Thanks all. 

   I kind of think like Mike - a circ saw wants to go straightish, a router anyway it can think of going.

   If the pieces weren't so big (~3x4) I'd use a tablesaw, but that size is beyond my comfort level. 

   Oh, and don't expect results soon, LOL.

9. 
   mike4244 | Feb 21, 2009 05:56am | #11

   Certainly, I cut grooves for cabinet backs with two 24 tooth blades and shim stock spacer for years. Another way for wood only ( not plywood or mdf) is to increase the set of a single blade.We used to do this on a skill saw 7 1/4" blade for certain operations where a table saw was not an option. Routers will do the job with either slot cutters or a straight bit, We used a saw because it was much faster and easier for production work.

   mike

1. 
   EdHarrow | Feb 25, 2009 09:55pm | #12

   Proto cut is perfect! 

   Now I have to make the jig to ensure the cuts (I hate to call them dados) are on the correct center.  As before, don't expect results soon.  ;-)

1. 
   EdHarrow | Mar 03, 2009 11:49pm | #13

   Looks 'great' (well looks like it should look anyway, a bunch of equally spaced grooves cut in a 3x4 piece of plywood).