Deep dado

[Dave Cottrell]

What is the best way to clean the bottom of a 3/4" deep dado? I am using 2x4's to build a workbench and do not have a router plane.

[mike holden]

A swan-neck chisel comes to mind, but it would be as expensive as a good used router plane.
Could buy a large allen wrench and sharpen that as a tool. Or if you have a torch, bend a file and sharpen the tip.
But really, why are you concerned? Is it going to show? Otherwise just clean out enough with a straight chisel to give clearance for what ever is going to go into the dado.
Mike

[John Thompson]

If the dado is through.. I do it with two very light passes with a LV medium shoulder plane which is a few .000 shy of 3/4". One pass one direction.. another the opposite to catch the other sides corner. Done!

Sarge..

[Jim Becker]

Like John, my first recommendation would be a small/medium shoulder plane if available; otherwise, some form (or several) chisels come to mind. You could also fashion a small sanding block that could run through the slot.

[Steve Hamlin]

Block with a through mortice, chisel held in position with a wedge. Vertical mortice = scraper; angled mortice = OWT.
Since it's a deep dado and just levelling up the floor, shouldn't have to bother with chip clearance either way.

[Doug Shepard]

Forstner bit.

[Jeff Myer]

I just had to do this exact operation over the weekend working on my sawing bench. In my case, I was creating dados for the 2x4 stretchers to join the 2x4 legs. Each dado was 3/4 deep by 3-1/2 wide

I cut the sides with a hand saw and started hacking away with a 1" bench chisel. By my 4th dado, the bottom started to look decent but nothing show worthy.

The good news is that the mating 2x4 fits perfect and nobody but me will know how ugly the bottom of the dado is. I had a thought of running the Record 778 that I bought at a yard sale this weekend through without its fence on but the blade was chipped so I decided to let it go as the joint fit fine.

Hope this helps.

[John Thompson]

If I ddn't have a medium shoulder plane and when doing non throughs.. Steve's method using a chisel as a scraper is my method with an exception. I use my marking knife or an Exacto knife with the outer wall as reference and make a paring slice at 90* degrees down where bottom meets side.

Then I go after it with a vertical chisel hold using it as a scraper pulling toward me.. no block, just one hand down on the bevel and one to the end of the handle. A block would be best till you get the feel as a jig for sharpening is good until you get the feel.

Sarge..

[Dave Cottrell]

Thanks for all the responses. I just got power back on after losing it this morning due to a storm. Needless to say, I was still working on my bench sawing lap joints!

The dados I am working on are for supports for a bench top that go between the side aprons. I guess my main point was even though this is an invisible joint, I assume any glue will work better between two flat surfaces. The joint looks OK from the outside and the pieces fit, but I know the bottom of the dado is all torn up and uneven. Without any of the tools you guys mentioned on hand in order to make a clean mating surface (and hence a good glue joint) I am considering installing dowels across the grain in the top support, and using screws long enough to go through the apron into the end grain of the support and through the dowel's long grain. Or is this overkill?

I have been looking for an excuse to get some sort of shoulder plane. This may be one of those slope moments.

[Robert Rozaieski]

Think about what you are asking the joint to do before you make any cuts (unless you already have). A dado is not a strong joint. The glue bond is an end grain bond. There is no long grain to long grain contact so under any kind of load/stress, the joint will fail. If you want to connect the two side aprons with a piece down the middle, I'd suggest a different joint, like a mortise and tenon. I wouldn't use a dado for any part of a workbench. There are just too many directional forces to be supported and such a weak joint is not designed to support them.

[Danny Thompson]

Experts, if the goal is simply to "clean up" a ragged dado floor, rather than to enforce a certain depth, wouldn't a chisel with the bevel down flat against the floor work?

[Jason Roehl]

Experts, if the goal is simply to "clean up" a ragged dado floor, rather than to enforce a certain depth, wouldn't a chisel with the bevel down flat against the floor work?

I see Roy Underhill do it all the time.