Cutting stopped dados

[Jon Snider]

What is the safest way to cut stopped dados or rabbets! These will be approx 1/2” wide cuts in 2 - 2 1/2” wide fairly soft wood (Port Orford Cedar). They are used as part of a water drainage system for deck of boat.

For example, there may be a cross frame piece which is say 42” in length running across the beam of the dory deck. The only area which might need the dado or rabbet might be a 30” section in the middle into which the hatch lid fits. There are numerous variable for each bulkhead so need to individually cut rather than gang cut.

I’ve seen it done on a table saw twice, by an excellent craftsman. I have no interest in repeating that.

Ideas include a router table although not sure how to start the cut. I could use a plunge hand held router but the pieces are pretty narrow (could use a wider board and then rip to width later).

Another thought is to dado the entire length, and the cut a strip to epoxy back in the areas that need no dado.

Any other ideas? Thx much.

jon

[glenn bradley]

Drop cut / stop cut on the router table. A stop block determines your starting point. You plunge the cut either by lowering onto the spinning bit or pivoting into a slot cutter as shown here.

pic-box-stopped slot- (1).jpg . pic-box-stopped slot- (2).jpg

pic-box-stopped slot- (3).jpg

You move the material to the second stop block that determines the length of the cut and pivot or lift off of the bit.

pic-box-stopped slot- (4).jpg . pic-box-stopped slot- (5).jpg . pic-box-stopped slot- (6).jpg

You can adjust the depth and repeat the operation for deeper or wider cuts.

I swear I have pictures of a stopped dado around here somewhere but, quickly came up with another example of a stopped cut using a side cutter as opposed to a straight cutter like for a dado. I think you get the idea of the stops and fence though.

CB with Inlay (12).jpg . CB with Inlay (13).jpg

[Jon Snider]

Thanks Glenn! Also found this. https://www.youtube.com/watch?v=muIpGZrwIRs.

[Lee Schierer]

You can cut the dados safely on a table saw.

First you set the width and depth of cut with your dado blade.

Once you are satisfied lower the blade using the raise lower handle noting the angle of the handle and how many turns it takes to lower the blade completely below the table top.

Then you set your fence to the proper distance.

You set stop blocks behind the piece where you want the cut to start. You also clamp a stop block in front of the piece where you want to stop.

With the blade lowered and off, place the work piece in place against the fence and back stop. Hold it in place, turn the saw on. Slowly raise the blade the same number of turns it was lowered. Push the piece through the cut to the other stop block and lower the blade the same number of turns. Turn the saw off and remove the work piece.

Repeat as needed.

[Jon Snider]

Thanks Lee. I’m might try that. Only issue is depth of dado and number of turns of handle.

On the wider pieces, the dado is 1” wide and 1/2” deep. Seems a bit much for a single router table pass, even in soft wood like POC? But I’m thinking it might be hard to make multiple passes and keep things aligned.

[Lee Schierer]

It works pretty well for depth. Try it on some scrap first.

[David Buchhauser]

Another thought is to dado the entire length, and the cut a strip to epoxy back in the areas that need no dado.

Jon,
From a practicality standpoint, I like your idea of dadoing the entire length, then plugging the ends. If money were no object, then a large cnc router table might possibly be the absolute safest way for the blind dados.
David

[Thomas McCurnin]

I find that dropping a piece of wood onto a spinning router bit gives me inconsistent results, so I have to make up several extra pieces for practice, set up, and mistakes.

If this was only a few dados, I might consider using hand tools, e.g., knife wall, chisel work, and finish with a router plane. That could be spot on deadly accurate.

[Rod Sheridan]

It's easy to do a stopped groove like that on a shaper, it's called insertion molding.

As others have said, it can also be done on a table saw, use stop blocks and raise the blade for each groove, shutting off the saw before placing or removing the piece on the saw..........Regards, Rod.

[Derek Cohen]

One could always just use a simple guide with a stop for a router ...





Otherwise, use a saw ...



.. and chisel ...



And a different kind of router (plane)



Regards from Perth

Derek

[Andrew Seemann]

If dadoing the whole way and epoxying in a piece is acceptable (and it sounds like it is), it is hard to find another way that is faster, safer, and more accurate. I wouldn't hesitate to use that method.