So I'm still in the "mostly fiddling around" stage with my ShopSmith. But I'm wanting to tackle a real project...a cart for the various ShopSmith "Special Purpose Tools".

 

The plans call for a "blind dado" to hold the top and bottom of the cabinet back. I tried routing on the ShopSmith for the first time last night...nothing critical, just making a hardboard panel to cover the rusted-out top panel of a chest deep freezer until I can afford to buy another one and had to rout out a few square inches for the nameplate and handle. Had a little difficulty stopping exactly where I wanted; final result is a little ratty. Not a problem on a rusty old deep freeze, but I want to do better on my first real piece of furniture.

 

The panels where the blind dado will be are much larger than the small table of the ShopSmith. Ideally, I'd like to be able to slide the workpiece back and forth over the dado blade to cut about a 3/16" slot to start the blind dado and then turn it over, set up for routing, and use a 1/4" router bit to finish the slot precisely. But since I don't trust my ability to freehand it, I'd like to have something I can use as a guide and set a positive stop on each end of the workpiece travel. Possibly something which I could clamp or hot glue under the workpiece which would ride in the table's miter slot. Any suggestions?

dado blade on the table saw?  lower blade, move work to start position, raise blade, move work, stop moving at end position, lower blade.  clean up with chisel as needed?

Is there a reason you don't to cut the dado completely with the router? I've never tried to cut a blind dado on a table saw.

Again, I'm new to this and I found that it wasn't quite so easy to keep the workpiece under control with the router. I've just been looking at one of the aluminum miter bars which Rockler sells, though. I'm thinking now that if I hot-glue that to the opposite side of my workpiece and screw a stop block into it at just the right point, I can slide it back and forth under the router bit and then remove it with a heat gun after my blind dado is completed. (Might want to practice on a scrap piece first!)

I use one similar to this-

https://www.woodcraft.com/products/woodriver-50-clamp-guide?gclid=Cj0KCQjw78yFBhCZARIsAOxgSx26waHNp0FhFQXcuPpOKySNchvhq7eQA_ngRXoDd39uenCBa4Qpi7oaAp8FEALw_wcB

 

But you can make one from a straight piece of wood and a couple of C-clamps.

 

 

I've always used a straight edge of any type with my router, then stopped at my mark. As long as you are going in the right direction of travel, the router will stay snugged up against your straight edge.

59 minutes ago, John Morris said:

I've always used a straight edge of any type with my router, then stopped at my mark. As long as you are going in the right direction of travel, the router will stay snugged up against your straight edge.

Thanks. I'm not so much worried about staying on the straight line (I can use the fence for that) as I am overshooting the end marks and turning my "blind" dado into something the world can see....

clamp on a stop block at the end.

 

better to spend 30 minutes thinking it thru and getting it set up.  the cut will only take about 20 seconds.  do it right, do it once.

23 minutes ago, ehbowen said:

turning my "blind" dado into something the world can see....

It does happen @ehbowen, it does happen!

4 hours ago, DAB said:

better to spend 30 minutes thinking it thru and getting it set up.  the cut will only take about 20 seconds.  do it right, do it once.

Especially with the current price of 3/4" furniture grade hardwood plywood!

A trick that can be done on any table saw is to take the boards you plan to blind dado, set the board on the table, use a Sharpie to mark you start position.  Move the board to where you want the blind dado to end.  Again mark with the Sharpie on the table where you want the end of the board to be.  Set your blade depth, drop your board at the start mark, push it until you reach the ending mark.  After all the cutting is finished, you can wipe your table clean of the marks by using rubbing alcohol or mineral spirits.  I think Nick Engler did this on one of the Shopsmith videos.  I will take a look.  

 

 

I didn't find it, but here is a great link for a lot of information and you can see it done.  He is not a good spokesman, but he knows his stuff.

 

http://www.shopsmithacademy.com/Sawdust_Sessions.htm

 

 

 

Edited May 31, 20215 yr by FlGatorwood

Doing a blind dado on the table saw will be a problem. At the point you stop the workpiece the dado blade will leave a curved and tapered slot at the end which will be difficult to clean up with a chisel. It would be better to use a hand router with a collet using a straight edge and a stop block. The straight edge and stop block can be made from scrap plywood. It will look like a reverse L. The straight edge made of plywood needs to be 6-8” wide to allow you to clamp it to the workpiece and have room to run the router past the clamps. A plunge router will make this job easier but it can be done with a standard router. Hope this helps. If you need to see a picture of the jig and the router setup let me know and I will post one. 
Paul

Here's one approach:

 

1. Use a plunge router with a straight bit and bushing or top piloted bearing.  The bit can be slightly less than the width of he desired dado.

 

2. Determine the width of a guide track jig.  For the first option it will be the final desired width + the difference between the bit and the bushing diameter.  For the second option, it's just the desired width.

 

3. Take a piece of scrap plywood and rip it in two.  On one of the pieces, rip off another strip the size in step 2.

 

4. Cut that strip in half.

 

5. Glue the pieces back together, leaving an opening in the strip to yield the desired length of the dado (use math in step 2).

 

6. When glue is dry, clamp the jig onto your board and route out the dado/groove.   Square up the ends with a chisel.

 

I've used this technique many times to excavate out hand-holds in panels.

 

 

Edited June 2, 20215 yr by kmealy

Here's photo of one of my jigs

Another approach that showed up today https://www.finewoodworking.com/2020/10/01/how-to-cut-stopped-dadoes-on-the-tablesaw