Dado blade on a Shopsmith

heathicus · Post by **heathicus** » Mon Jun 14, 2010 4:12 pm

My parents just gave me a Rockler gift card for my birthday so I'm looking at getting a stacked dado set finally (to upgrade form the wobble dado I have that cuts fine but is a real pain to adjust).

Is a 6" dado set adequate, or should I get an 8" set?

What would be the maximum depth of cut with a 6" and is it likely I'll ever need the extra depth that an 8" would give me?

JPG · Post by **JPG** » Mon Jun 14, 2010 4:30 pm

Personally, I went for an 8" one. In any event, it can cut one inch deeper!

Measure the distance from the center of an arbor(5/8" 'universal'/molder/shaper) to the top of the table with the table lowered fully(probably easier to do this with the insert out, and measure down to the arbor center.

Subtract this from 1/2 the blade diameter, and you get the max depth of cut.

I would measure it myself, but my work table has a headstock being assembled setting on it which I do not want to move.

With a 1 1/8 HP motor, the 8" should do fine. If 3/4HP motor, perhaps the 6" is more appropriate!

P.S. Happy Birthday!!!!!

billmeyer · Post by **billmeyer** » Mon Jun 14, 2010 4:49 pm

Most Dados are shallow cuts, so I went with a 6" and I don't regret it. I use it on my table saw, and have not had the need to try it on my SS.

Bill

mickyd · Post by **mickyd** » Mon Jun 14, 2010 5:48 pm

First, HAPPY BELATED BIRTHDAY!!

Second, do you have your blade style picked out yet? I've recent used mine for the first time and noticed that I don't get a dead flat bottom due to the tooth geometry. The teeth on the outer blades are beveled and a smidgen taller than the inside chippers. It leaves "bat ears" in the corners and when making several passes, noticeable grooves across the bottom. Don't know if this is due to the quality or type of blade I have but just wanted to throw it out there for consideration and comments.

Regarding the size to buy......????? I'll follow this thread to see what others recommend.

osx-addict · Post by **osx-addict** » Mon Jun 14, 2010 6:34 pm

I thought there was an issue with some SS models not being happy with an 8" blade -- perhaps on the 3/4 hp models? I might be mis-remembering though!

heathicus · Post by **heathicus** » Mon Jun 14, 2010 7:24 pm

I was looking at one of the Oshlun stack dado sets.

6" set for $69.99:
http://www.rockler.com/product.cfm?page=17313

8" set for $89.99:
http://www.rockler.com/product.cfm?page=17335

The gift card is for $50 and Rockler also has a 15% sale going on right now. So for cost reasons, I was thinking of getting the 6" set. The reviews on both sets are pretty good.

And thanks for the birthday wishes!

robinson46176 · Post by **robinson46176** » Mon Jun 14, 2010 7:41 pm

osx-addict wrote:I thought there was an issue with some SS models not being happy with an 8" blade -- perhaps on the 3/4 hp models? I might be mis-remembering though!

I believe that the only actual problem with an 8" on a Shopsmith is some guys inability to cut a 2" deep dado in oak at a feed rate approaching a fast run. It's the IG factor

Somewhere in my "stuff" I have a 4 inch stacked unit. I've never used it but I have yet to see why I would more depth capacity than it has but I suppose some might do work where deeper might be needed.

jonesuh · Post by **jonesuh** » Tue Jun 15, 2010 11:36 am

i bought the Amana 6" from SS very happy flat bottoms very easy to get the exact width needed

8iowa · Post by **8iowa** » Tue Jun 15, 2010 12:56 pm

It's all about the amount of cutting torque at the tip of the dado's teeth. The Shopsmith, along with all other saws in the "underpowered" classification (saws that are designed to operate on a standard 15 amp household circuit) will have more torque at 6" than at 8". If your dados are not more than around 1/2" deep there probably isn't much difference to be noticeable, and of course, on the Shopsmith we have the option to reduce blade speed and gain torque.

I have the Oshlun 6" dado set and it does a good job on everything except plywood, where there is a lot of tearout. Dado sets with negative hook angles have less tearout, although plywood would probably still be a problem. For plywood, you will have to score the cut first and/or use masking tape in order to get cleaner dados.

robinson46176 · Post by **robinson46176** » Tue Jun 15, 2010 10:57 pm

The 4" dado set I mentioned before has teeth much like the teeth on an old loggers crosscut saw. I have not tried it at all but I wonder if the cutting style with the edge scoring teeth might do well on plywood.
Here is a page with a good basic coverage of crosscut saw teeth.
http://www.fhwa.dot.gov/environment/fspubs/04232822/page04.htm
I could handle my end of a saw pretty well by the time I was 12. Before that my father used to yell at me... "I don't care if you pull on the saw or not just quit dragging your feet."