max depth of dado in one pass -

[Philip Berman]

Hello -

I need to do a bunch of dadoes that require a blade height of 1 1/2", total dado to be 3 1/4?" wide (for an assembly table base). Using 3HP Delta cabinet saw, Ridge stacked dado set, can I go the full 1 1/2" deep X 3/4" in one pass, or am i asking for trouble? I need to keep the shoulders aligned properly and it seems that one pass at each shoulder line is easier to do (and keep a clean line) than taking multiple passes with the blade progressively higher. ?

thanks

Phil

[Carl Beckett]

I will let other experts weigh in on this, but I dont think I would be comfortable with this. Can you share more about how you will be feeding and securing the workpiece? (as important as the cutting forces is the manner in which you ensure the workpiece is fed squarely and without risk of binding due to something moving or residual wood stress)

The first pass in particular would scare me.

What are the workpiece dimensions and how would you feed this? (using a miter or crosscut sled or other?)

[Philip Berman]

Yeah, I'm obviously not comfortable either, so I probably just shouldn't do it. 4x4 doug fir, using a miter gauge. Pieces are only 24" long, so they're easily managed. I supposed I could incrementally raise the blade, leaving each shoulder for the end, at full height but only taking a bit off to clean it up. Seems dopey to stop and build a new sled with a dado slot just for these 4 legs, especially since I now have a 4'X6'X4" torsion box plopped in the middle of the shop awaiting said legs and am having trouble moving around the shop as it is. I guess it'll just be a lot of starting and stopping of the saw to get there. Unless someone else has a better idea. Maybe I should just make a couple of kerfs at the shoulders and chop out the middle with a chisel - sounds like that would be faster.

[Matt Roth]

I think you almost answered your own question; make a couple full depth passes with a regular blade to establish the shoulders, then use your dado in incremental passes to plow out the remainder.

[Larry Edgerton]

Establish your edge/edges with a single blade to depth in one pass. Then lower your blade aprox a quarter, make a few passes about a half apart with a single blade. Clean that out with a chisel, and then go back and make your final passes with the dado blade or a router. Most dado blades leave a deeper cut on the outside, so a router at this point would be my choice.

I make cuts like that with a dado, just a hare shy of full depth, but I have a 7.5hp saw, not sure what you have.

[Bill Huber]

I really don't see a problem here. the feed rate is going to be the key, a very slow feed rate and a 3 hp saw should have no problem.

I would clamp a board to the table saw as my start point and then clamp a stop on the fence for the end point. If my miter guide was a short one and didn't have a long face I would put some type of a long face on it and then go to cutting, very slow feed rate.

I just don't see the difference in cutting a 1 1/2" dado or a 3/4" dado if the feed rate is slow.

[Philip Berman]

thanks everyone - I just did them in a couple of passes, saving the last 1/16" for a full-depth cut at the shoulder-lines. Doug fir really does cut like butter, had a very firm grip on the work, but was still a bit nervous about the full-depth cut in one pass, so I guess better to err on the side of caution. Thanks again for the input.

Phil

[glenn bradley]

Quality of cutter, power of saw and feed depth/rate are some of your factors. I assume your 2-by material has been milled square. If I was in a hurry I would put a 3/4" stack on my saw and take 1/4" to 3/8" bites. I already have a sled for dados and so would use stops to control my left to right positioning so all legs would be identical.

I too am wary of that much dado stack height so I would be more inclined to do this sort of thing on the tablesaw/bandsaw. Two vertical cuts on the tablesaw to set the boundary and then clean out the spoil on the bandsaw.

Ooops, just realized I am too late ;-)

[Peter Quinn]

I guess its done, but for next time if you have a BS it makes easy work of removing the bulk of the waste, then you only have to make a few very light passes full depth. If its in the middle of a board you can come make two cuts just shallow of your layout, then swoop in on a curve from each side, if its from the end like a tenon its even easier, and it leaves you a lot less saw dust to deal with.