Systimatic Dado concerns...

[Chad Stansbury]

Hello all -

I've recently purchased my first set of dado blades from Woodcraft, and deciding that at ~ $180 I couldn't go wrong with the Systimatic set (believing that they've got to be great to cost so much). At any rate, I used them on my latest project by cutting dados in some oak-veneered 3/4" plywood... and was very dissappointed with the amount of tearout I got. Caveat: I'm using the vanilla Jet dado throat insert, and therefore the wood had very little support... However the same can be said of the throat insert for my Forrest WWII blade, which had significantly less tearout.

Question is, did I possibly get a bad set, or would buying a zero-clearance insert help matters greatly?

Thanks in advance,

Chad

[Morgans]

zero-clearance

Make your own. Get a piece of hardwood, plane it down, use the current insert as a pattern to trace, and cut it out. I sometime take the time to put adjusting screws in it, by countersinking for cabinet hinge screws, then use the grinder to take off the excess height. Works well. Make a bunch of them while you are at it. I have around 8 or 10 sitting on the shelf. Make blanks, then plunge up through them, by putting the rip fence over the top a little bit, and a push stick on the other side to keep it from coming up.

[Lawrence A. Ramsey]

[Dave Mundt]

Well, first off, a zero clearance insert - which as other posters have mentioned should be MADE by you - will help a lot. I make mine with a bandsaw and router. I use the original insert to mark an insert on a plywood blank, then, rough cut it (to within

1/8") with the bandsaw. I then fasten the blank to the original insert (which is, by the by, made of 1/2" thick plywood) with double-sided foam tape, and use straight pattern bit in the router to clean up the outline. I cut the slot in the insert by putting the blank in the saw, with the blade cranked all the way down, and, after clamping the fence over it (to hold it down) in an area clear of where the blade will come through, I turn the saw on, and crank the blade up through the wood. Works like a charm. However, veneered plywood is still a royal pain in the butt to cut without splintering. I think that PART of the problem is that the surface veneers are so thin these days that they have, essentially, NO structural strength, and, so a stringy sort of wood like Oak is going to want to make long splinters that tear off easily. Another thing that helps a GREAT deal is to use a straight edge and utility knife to "prescore" the edges of the cut. A single, firm slice down the layout line on each side of the cut will go a LONG way towards keeping tearout to a minimum - even if you don't have a zero-clearance insert. Regards Dave Mundt

[Lawrence A. Ramsey]

[Brian]

I use a laser machine to cut mine out...Ican cut a years supply of them in an hour or so during lunch......Brian