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gorillapaws's avatar

Woodworkers: What tool is the most appropriate and affordable for making many large dado cuts?

Asked by gorillapaws (30444points) April 1st, 2013

I’m planning on making a fence from many panels of lattice made up of pressure treated 2×2’s. In order to make the 2×2 lattice, I will need to make many cross-cut dados so the 2×2’s will lock together like Lincoln logs. I found a clip of Bob Villa doing something very similar to what I have in mind. He’s using a pretty fancy radial arm saw with a dado blade.

I don’t have the budget (or room in my house) for large specialty tools like that one, so I’m looking for a more practical alternative. I looked into a table saw (a table saw would be a handy thing to have), but most of the entry-level ones don’t have enough amps to safely power a dado stack and as a result have short arbors that make it impossible to fit. The other option I can think of is getting a router, but it’s going to be tricky to build a jig that can make multiple passes for the same dado.

Any ideas and suggestions for what is the best way (affordably, safely etc) to achieve cross cutting hundreds of 11/16” deep dados, 1 3/8” wide into pressure treated 2×2’s? I would really appreciate any advice you could share. Thanks!

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17 Answers

Judi's avatar

I can’t think of any other tool but a router to do something similar.
You might want to check I just bought my husband this awesome 3¼ HP router that was not much more money but way better than any of the routers we found at Lowes or Home Depot. (It was only $299 last week.)

thorninmud's avatar

I’d do it with a table saw and a conventional blade. In fact, I just did.

Set the blade height for the depth of your cut. Mark the outer edges of the dado on your workpiece.

You’ll need to use your miter guide to guide the workpiece through the cut. Cut the two outer sides, then make two or three additional cuts between the sides like this.

Use a sharp 1” chisel to clean out the waste between the extremes. This is very easy.

The bottom of the dado won’t come out quite as clean as if you had used a dado blade or router, but the bottoms will be completely hidden in your project.

gorillapaws's avatar

Thanks for the great answers. The biggest concern with the chiseling method is the number of cuts I’m going to have to make, there is going to 16 dados per panel, and around a dozen panels, so that’s going to make hand chiseling a very tedious process. I wonder if there are affordable and relatively compact (collapsable) table saws that can accommodate a cross cut sled and a dado blade or stack because I think that might be ideal.

The next best option is probably a router. Thanks for the link @Judi. How does he like it so far? does he have any suggestions perhaps?

thorninmud's avatar

If you go with the router, you’ll might want to go all the way and get a router table. This will have slot for your miter guide too. Eliminates the whole jigging problem.

I have a hard time imaging using a hand-held router to do cross-cuts on a 2 X 2. Unstable as hell.

rebbel's avatar

I think I would go with one of these guys.
(Could be that I am repeating what someone above has said, but I am not familiar with Englisg names for power tools, so in case that that is the case, sorry).
You could put all your laths together in a row (held together with a clamp) and use the thing (from the photos), together with a guide rail, to make your dado cuts.
I would use the saw table method myself: first I’d saw the left cut, then the right, and then all the ones that are left between the two.
(Use a rail guide, and adjust the depth beforehand).
And last but not least, careful with your hands.

thorninmud's avatar

I really like @rebbel ‘s idea (that tool is what we call a “router”, @rebbel). That would work if you could get 2 X 2’s that will all lie in the same plane, otherwise your depth of cut will be all over the map. I don’t know if I’ve ever actually seen a straight pressure treated 2 X 2.

rebbel's avatar

@thorninmud Thank you for your router!

rooeytoo's avatar

I go along with a router. Although I rarely use a dado join, I am more of a dowel person. I think it is just as strong and for me, much easier. I have a cheapie router, it is a beast, weighs a ton and is hard to manoeuvre. With a better quality router I am sure it would be easier. I just finished a rudimentary computer desk to fit into a strange size area and I did it all with dowels and a couple of nails here and there.

rooeytoo's avatar

I just watched the vid, wow, isn’t life easy with the best tools!! It would take me 2 years to do that. The dowel method would work but it would not be as flat because horizontal would fit on top of the vertical instead of into it. I would have to try a small piece to see if it looked okay. With vines growing on it, I think it would be fine.

woodcutter's avatar

2×2’s are really 1½” x 1½”. In my experience that material is starting out weak and will be made yet weaker when material is cut out of it. I fear it won’t hold up very long exposed to the weather. No matter how tight and perfect all the joints start out they will open up slightly each one, each direction. The fact they may be pressure treated isn’t going to stop that. It does stop insect infestation though. Hope I’m not being a buzz kill. Things that are going to be outside need to be robust. That job seems like a lot of action to see it lose its structure to natural causes. Ever see a wooden picnic table made of 2×6’s after its been outside a couple years? Check out Harbor Freight Tools to see if they have the tools you need to do this work. That way you won’t be dropping a lot of coin for this project on tools. Cheap table saw, cheap dado blade, etc. Or at least get the blade and borrow a saw.

gorillapaws's avatar

Thanks so much for all of your helpful advice and GAs! At the very least, I can rule out that I’m overlooking a simple and cheap option that I might have been unaware of.

@woodcutter the 2×2’s I found near me weren’t even 1½” x 1½”, they’re measuring 1 3/8” x 1 3/8” (I’ve had to re-do all of my 1½” x 1½” drawings to account for this). Do you think I will have problems with the joints separating even with marine epoxy resin in the joints? What if I added a couple 18ga brads at each criss-cross lap joint, or a short decking screw? I’m not concerned with the fence being flawless in 5 years, especially because I’m planning on growing plants up the front, but I would be upset if it literally fell apart in a few years. I appreciate the reality check. In the video they were using even smaller stock 1” x 1”, is it ok because it’s a quality hardwood like cedar that they can get away with it? or will the trellis in the video likely have the same problems?

After hearing the different options, I think getting a good table-saw might make the most sense for me. By the time I buy a quality router and a router table, I’m not that far away from a good table saw anyways. Ultimately a table saw is something I’m going to want to have, whereas a quality router and router table probably won’t get very much use from me after this project—at least in the foreseeable future.

After scouring the web last night and reading a lot of reviews, I think the Bosch 4100–09 is looking like it might be the best option since it will fold out of the way when not in use and can accommodate a ¾” wide 8” dado stack, and seems to be well-loved by nearly all who review it. It’s more than I was hoping to spend (isn’t everything), but in the end I’ll have a quality tool that should last a long time and be useful for many future projects.

Judi's avatar

@gorillapaws, as my daddy used to say, “all it takes is the proper tool.
Unfortunately he never had the proper tool. My husband has, (in the words of the great Tim Allen) “Tools to fix tools.”

woodcutter's avatar

A good table saw will have lots of uses down the road. I have a router too but hardly ever use it. The thing with gluing wood that will be outside is, through expansion and contraction the glue will eventually lose hold so all that will be holding will be the fasteners. And even then, for the same reasons, they won’t hold nearly as well as they were right after assembly. A short deck screw there will keep most of its bite in spite of the wood doing its thing. To help them do this, pre drill and don’t over tighten them so the wood splits. If the wood splits, the joint is toast.

Here’s what I would do. Make the outside border out of wood and fill in the field with the plastic (many,many colors) lattice instead of the wood . The plastic panel substitution will last years and it’s pre made so you won’t have all that time invested stressing over those hand made notches. Last time I checked those lattices were maybe 12 bucks for a 4’x8’ piece and they saw and drill similar to wood. I still would pre- drill them to be safe.

gorillapaws's avatar

Here’s the first trellis section. I still haven’t screwed it and applied the marine epoxy to it yet, but it gives you a good idea of what it’s going to look like.

rooeytoo's avatar

Looks great. What tools did you decide to purchase and use?

gorillapaws's avatar

@rooeytoo Thanks! I went with the table saw I linked above. I built a cross-cut sled and some jigs to crank out the dado cuts one board after the other assembly-line-style. I have a lot more to do, but I think it’s going to work out. I really appreciate all of the above advice. I’ll be sure to post pics when I get the fence in the ground.

rooeytoo's avatar

You are going good! Look firward to seeing more pics!

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