Dado blade on a SCMS?

[Wade Samuelson]

Hi again,

I am going to be putting together a little stand-alone shelf unit for my wife (25" tall, with 2 shelves and a top). I plan to use a dado blade on the side pieces and then put the shelves in the grooves. However, the bottom shelf will be about an inch off the ground which means I have to cut the groove in the side piece accordingly. I don't have a crosscut sled for my little contractor table saw, and I don't know how I would slide the two foot side piece along uniformly and a cut my groove an inch from one end.

Can I put my dado blade on my SCMS? It will cut the 12" side piece. Or is there a way to make it work on my TS?

Sorry if I didn't explain that too well, but I would appreciate any help you have. Thanks!

[Hoa Dinh]

I don't know about a dado blade in a SCMS. I don't have one. I wouldn't put a dado blade in my CMS.

I'm unclear as why you can't use the TS to cut the dado.

Assuming you are using sheetgoods for the sides, I would prepare a piece 25" long and a bit wider than 24", cut the dados, then rip the sheetgoods piece to get 2 25"X12" sides of the shelf unit. I'd use the TS to cut the dados, with the rip fence guiding the cuts.

Or you can use a router with an undersized straight bit (e.g. 1/2" dia. straight bit for 3/4" plywood shelves) and a simple two-fence dado cutting jig.

If you have access to a biscuit joiner, use it instead of cutting dados. I think that's the fastest way.

[Tom Hintz]

SCMS are onot designed for dado blades. Most of them do not have room in the upper blade guard for it anyway but if you could get it in, it would be very hard to control which means it is very dangerous.
If you can't make the cut on the table saw, use a router with a clamped-on fence to guide it. Make a couple passes if you do not have the right size bit.
I have a jig I use for such things at the link below that might give you another idea.

http://www.newwoodworker.com/autodadojigpln.html

[Charlie Plesums]

I rarely use my dado blade - I find the router follows the variations in the plywood better, giving a constant depth dado. Any warp in the plywood sides can be taken out when they are glued to the shelves...if you have a consistent depth of that dado.

[Jim Becker]

No dado on an SCMS (there was one I think that "could" take one) but no-way would I want all that metal spinning on that kind of tool. A router and guide is probably the easiest, safest and most efficient way to do your dados for this project. IMHO, of course...and you know how much that cost you... ;)