Best way to stopped dadoes in narrow pieces?

[jking]

I am planning to build a wall mounted display cabinet for my son's collection of mini football helmets. The total depth will only be about 2 1/2". The shelves will be dadoed into the vertical parts of the cabinet. There will be four shelves about 3" apart (vertical spacing). I don't want the dadoes to be visible on the front.

My plan was to rip a 1/4" strip off the front of the vertical pieces, cut through dadoes, and then glue the strip back on the front. It seems like a lot of work, but, I can't think of a better way. I thought about using a router, but, I have doubts about being able to do a stopped dado in a narrow workpiece. Does anyone have a better idea?

[atgcpaul]

I don't think ripping, dadoing, then gluing sounds like too much work. You only have to glue on two edges and ensure they don't slide around.

Were you going to do the dadoes on a router table or freehand with a guide? If you have a way to guide the shelf through the bit (I think this is the bigger challenge), just setup a stop block so you don't blow through the front.

[Carpenter96]

I think your solution would work quite well and is the simplest. A router table with stop block and crosscut sled would also work. Regards Bob

[cabinetman]

If you do a "stopped dado", you'll need to chisel out the corners.

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[jking]

I don't think ripping, dadoing, then gluing sounds like too much work. You only have to glue on two edges and ensure they don't slide around.

Were you going to do the dadoes on a router table or freehand with a guide? If you have a way to guide the shelf through the bit (I think this is the bigger challenge), just setup a stop block so you don't blow through the front.

I was concerned about keeping the edges from sliding around while gluing back on. I'm planning to use a dado set and table saw to cut the dadoes. I don't have a router table, or, I'd consider using that. Thanks.

[JR]

I was concerned about keeping the edges from sliding around while gluing back on.

Here's how to make sure you keep the pieces aligned during glue-up: use a couple/few veneer clamps.

Mine are made from 2by stock. The faces are chamfered ever so slightly, assuring tension all across the material. Packing tape on the faces keeps the glue from messing everything up. 5/16" bolts driven through holes in the cauls, with hex nuts or wing nuts, provide the clamping force.

Slip the two pieces you're mating together between the cauls, clamp them together using f-clamps or, ideally, bar clamps, then tighten down the bolts on the veneer clamps (maybe sneak up on the bar-clamp/veneer clamp sequence a bit, like you're torqueing down the head on an engine block). Voila.

I have maybe a dozen of these in my shop. They're useful for the application your proposing, which I have done several times, as well as gluing up panels or applying veneer. Once the squeezeout is removed, you should expect to use nothing more than a cabinet scraper to finish the work.

HTH,

[atgcpaul]

If you do a "stooped dado", you'll need to chisel out the corners.

.

I don't agree. The shelf will essentially be a haunched tenon and would completely cover any rounded corners created by the router bit. I suppose a flat spot could help with registration during glue-up, but it's not necessary and would also require exact handwork with the chisel. User error could actually widen the dado and create a gap.

[cabinetman]

I don't agree. The shelf will essentially be a haunched tenon and would completely cover any rounded corners created by the router bit. I suppose a flat spot could help with registration during glue-up, but it's not necessary and would also require exact handwork with the chisel. User error could actually widen the dado and create a gap.

Chiseling the round out would allow more of the "tongue" part of the shelf to seat. With a short dado to begin with, having more of a step to cover the gap might shorten the "tongue/tenon". It's not really a "haunched" tenon, but rather a notch on the shelf, and a dado that doesn't run through.

.

[Brian G]

I'm assuming 1/2" stock for this project, but my approach is the same if it's 3/4" stock. I'm also assuming that the mini helmets are so light that deflection isn't going to be a problem.

If the total depth of the sides is about 2-1/2", I would opt to start with a 5-1/2" or wider board from which you will mill the two sides, crosscut to final length. Using a square, mark out where you want your shelves to be on the 5-1/2" wide board.

I would use a plunge router fitted with a 1/4" straight bit and 1/2" o.d. guide bushing to make "double stopped dados" in the 5-1/2" board by:

1. On each edge of the 5-1/2" board put a mark where you want the front of the shelf to stop, and then another mark 1/8" (or slightly more) where the dado will "stop". The 1/8" equals the offset (1/2" o.d./2 - 1/4" bit diameter/2) of the bit and guide bushing. This establishes the stop.

2. Clamp a straight edge (e.g., a piece of mdf, ply, jointed board) along the line you marked for the first shelf.

3. Butt the thickness of the shelf against the straight edge, and then butt another straight edge snugly against the shelf and clamp the second straight edge. Pull out the shelf. This gives you a "channel" for the 1/2" bushing guide to run through.

4. Set the plunge depth to to however deep you want the dado to be. With the router UNPLUGGED(!) plunge the bit so it kisses the stock. Align the cutting edge with the mark you made that establishes the dado stop. You can then screw a stop block across the two straight edges (use two screws per straight edge) butting against the router base, and do this for both edges. Now you have one-time jig to guide you for the rest of the dados.

5. Route the stopped dado, then unclamp the jig you made, line it up with the next stopped dado, and so on down the line until you are done.

6. Rip the 5-1/2" board (stopped dado edges next to the rip fence) into the width you need for the sides.

7. Cut the shelves to your planned length (remember to account for the depth of the dados!).

8. The dado will be (in this case) 1/4", so you will need to use your dado blade to cut shoulders in the ends of the shelf boards to fit the dado.

9. You can, as cabinetman noted, chisel the stopped dados square, or as also suggested you can notch the end so that the "tenon" fits the stopped dado. Either would work, but I think a notch is quicker because you already have the dado blade mounted in the tablesaw.

There are other ways just as good or better.