Best Dado Set Question

dusty · Post by **dusty** » Sat Mar 26, 2011 11:13 am

I understand that a flat bottom is desired if the end of the dado can be seen and if appearance is important.

But other than aesthetics, are there any reasons why the bottom needs to be flat?

I have the Shopsmith adjustable 6" dado blade and a Freud 6" Stacked Dado Set. I normally reach for the adjustable dado when I need a dado.

JPG and I may not have the same adjustable dado. The one I have is very easy to adjust and it need not be removed from the arbor (though the arbor nut must be loosened to adjust). No, I do not get a flat bottom in the dado but then I am not sure that matters for the work I do. Aesthetics is seldom an important factor. I don't do fine furniture.

Aah, none of this matters! I see that Leland has purchased a Dadonator of which I know nothing.

algale · Post by **algale** » Sat Mar 26, 2011 11:25 am

dusty wrote:I understand that a flat bottom is desired if the end of the dado can be seen and if appearance is important.

But other than aesthetics, are there any reasons why the bottom needs to be flat?

I have the Shopsmith adjustable 6" dado blade and a Freud 6" Stacked Dado Set. I normally reach for the adjustable dado when I need a dado.

JPG and I may not have the same adjustable dado. The one I have is very easy to adjust and it need not be removed from the arbor (though the arbor nut must be loosened to adjust). No, I do not get a flat bottom in the dado but then I am not sure that matters for the work I do. Aesthetics is seldom an important factor. I don't do fine furniture.

Aah, none of this matters! I see that Leland has purchased a Dadonator of which I know nothing.

Have the Dadonator and can vouch that it is great (although I use it on a Craftsman contractor saw). As far as Dusty's question goes, I think there could be more than aesthetics at issue. A round bottom dado won't have quite as much surface contact with whatever is being inserted into the dado (assuming that the piece going into the dado is flat on its edge and not cut on a radius to match the bottom of the dado. Other things being equal, I would expect the flat bottom dado to make a tighter joint.

dusty · Post by **dusty** » Sat Mar 26, 2011 12:04 pm

algale wrote:Have the Dadonator and can vouch that it is great (although I use it on a Craftsman contractor saw). As far as Dusty's question goes, I think there could be more than aesthetics at issue. A round bottom dado won't have quite as much surface contact with whatever is being inserted into the dado (assuming that the piece going into the dado is flat on its edge and not cut on a radius to match the bottom of the dado. Other things being equal, I would expect the flat bottom dado to make a tighter joint.

I understand your logic but the bottom is almost flat. Guess I better go cut a dado and really look at it for this purpose. I've never done that.

Yes, glue bond would be somewhat better if the bottom surface nearly matched what is being inserted Strictly speaking, the strength of the joint is improved if the dado is not cupped.

garys · Post by **garys** » Sat Mar 26, 2011 1:51 pm

I used a wobble dado for about 20 years. It was adequate for anything where the curved bottom of the groove wasn't important. I always wanted a different one I could shim up and have it cut flat bottom dadoes.

Recently, I purchased a low priced 8" dado made by Mibro. I'm pleasantly surprised. You can buy it for under $50, and it performs as well as I could want a dado to perform.
It is made in China like most products today, but the quality of the carbide blades seems very good.

keakap · Post by **keakap** » Sat Jun 11, 2011 5:39 pm

ddvann79 wrote:...adjustable Dado head. Nice shape. These are far superior to the stacking Dado cutters. First, the bottom of the cut is flat and smooth, ...

That ad copy was obviously written by somebody in the Obama administration.
What a load!

I've got both the SS (VA) wobbler (first) and the SS Amana 6"er (finally).
The wobbler will cut a flat bottom at ONE width (think about it) while scaring the beegeesus outta ya (admittedly irrationally).
The Amana has been excellent, 100%.

paulmcohen · Post by **paulmcohen** » Sun Jun 12, 2011 6:04 pm

Now that you can get a 6" Dadonator (I have the 8" and paid close to $200) on sale for a great price that would be my choice today with a Mark 5.

With my new PowerPro I love that fact that I got the 8", on the 510 it took a while to get up to speed when doing a 3/4" dado because of the mass of the blade.