DEEP dado - help?

[Bill Karow]

I've been asked to help out my neighbor with a small project, and I'm stumped as to how best to do one particular cut without ending up with chisel work.

He wants to be able to cut a dado into the END of a (short) cedar post 4x4 to be able to inset a 2x4 in it perpendicular to the post, so that there is a dado 1.5" wide and 3.5" deep in the end of the 4x4.

With the cabinet saw, I could use a tenoning jig and a dado blade to make a good bit of the cut, or a regular blade to make it a little deeper, but they won't get to 3.5" deep. I've got a good selection of routers, but none AFAIK would be suitable to go that deep unless I'm using a really long bit.

If anyone has suggestions to get this cut made safely, preferably without finishing it off with a lot of hand chiseling, please let me know! Otherwise, we may dado the sides of the 4x4 and cut the 2x4 to fit between them, but we'd like to avoid that if possible.

Thanks for any help the collective can provide...
Bill

[Michael Cody]

Unless you are doing dozens of them, why not a little chisel work. Just use a hand saw and cut two slots 3.5" deep & 1.4" wide, then chisel out waste and pare to fit. If you have dozens rig up a jig to cut the slots with a Circular saw and chisel from there. I don't how this is going to take more than 5 minutes per post. Lastly if you are putting this outside, then all the posts are going to spilt when the 2x4 swells unless you leave some slop in the split.

[David Wilson]

Bill
You can use the tennoning jig with a standard blade. Make 2 precise cuts to define the outsides of the cut and just nibble away the rest.

[Ken Fitzgerald]

Bill....I can come up with a couple of ways......

1. Draw the desire cut on the post. Use a hand saw to cut to the bottom of the desired cut on each side. Then use a coping saw to connect the two side cuts.

or

2. Use a router with a shop made jig or freehand if you're comfortable. Plough out the body of the tenon and a coping saw to square up the corners. A 4x4 is only 3 1/2" so you'd only have to cut 1 3/4" deep if you approach it from opposite sides of the post. Chisel if necessary but you'd only have to worry about the corners.

Good luck!

[Lee DeRaud]

You can use the tennoning jig with a standard blade. Make 2 precise cuts to define the outsides of the cut and just nibble away the rest.Even easier: same thing with a bandsaw. If you don't have one, this sounds like a good excuse to buy one.:D

[Jim Becker]

I also cut the sides of a bridle joint socket with the band saw...and then you can even remove the remainder by careful nibling after two curved cuts to remove most of the waste. It litererally takes a minute or two to do the complete job. Do the sockets first and then make the coresponding tenons on the mating piece(s) to fit.

[Ed Hardin]

Do not be intimidated by chisels. They are a great tool. Since I learned to sharpen the devils, my woodcraft Pfiel chisels are the second tool I grab for. Before Katrina my brother delivered a set of mismatched, don't know what, rusty, grinder sharpened (ha) chisels for me to clean up and sharpen. I sharpened and polished. Yesterday he called saying they are now the first tools he grabs doing repairs from Katrina.

[Chris Giles]

Bill

I would use an 3/4" drill bit and drill two holes clean thru the post right at the junction of the sides and bottom of the notch. Then use the bandsaw to cut the notch out. The drilled holes will make it easy to turn the blade 90* at the corner, then go back and square up the round corners, also with the bandsaw. No chisel, no hassle.

[Keith Christopher]

Or you could rip the 4x4 in half then, cut it like a halflap and glue it back up. BUT that is ALOT of unecessary work. I 3rd or 4th the bandsaw.

[Dave Falkenstein]

One more approach - use a hand saw or a band saw to cut the sides to the desired depth of 3-1/2 inches. Then use a 1-1/2 inch Forstner bit to cut out the waste to the bottom of the slot. Finally use a chisel, jig saw or coping saw to cut the radiuses left behind.

[Kelly C. Hanna]

I do this from time to time building Pergolas. Cut the two long 3 1/2" cuts (3 3/4" if the 2x4 is Cedar) with your circ saw first then finish up with a recip saw (Sawzall). Then you can get a long blade for your jigsaw and finish the cut...works like a charm and takes less than 5 minutes.

[Bill Karow]

Thanks to all who helped out. I knew I could count on you folks to give me a bunch of different approaches. Much appreciated!

[Donnie Raines]

I alos use the band saw to cut the "cheeks" and then use a dril press to bore out the bulk of the waste....a little work and it is clean.