Hi everyone,
What is the quickest, safest way to make a very large dado.
It needs to be 1 inch deep, 1 1/2 inch wide. Cross grain on the larger face of a 2×4. It needs to be easily repeatable as I will be making thousands of these.
Is this possible in one pass on any machine?
Thank you very much for any help you can lend me, I am stumped on this one.
Edgar
Replies
That's a big dado. The only thing that could cut a 1-1/2 inch wide dado in one pass is a router bit -- but certainly not a full 1 inch deep.
A dado set on a table saw can usually go to 13/16ths wide, so you could do each dado in 2 passes.
Cutting thousands of something is repetitive and boring, and also exactly the type of operation that can lead to injuries.
Yep, dado stack and two passes unless you have a machine that will spin a cutter that big and have the cutter. If you are truly looking at thousands I would look into tooling to handle that job.
P.s. that doesn't leave much of your 2x4 for any kind of strength. Is 3/8" or so enough?
Sounds like it might be a job for a radial arm saw. You could gang a bunch together, with a spacer to get your 1 1/2” width, minimizing the material handling.
Are you making thousands of these at once, or simply expect to do thousands eventually over tone? If all at once, I would strongly recommend contracting your local millwork or lumberyard and asking them to do this for you. When you take into account your time, safety, clean-up and wear on your equipment, I think you’ll be better off buying the 2x4s pre-cut.
If you’re doing batches over time, I agree that two passes with a dado is the way to go (unless you own an industrial-grade shaper). However, rather than cutting the left side of the dado in the first pass and the right side in the second, I’d suggest the following: make a 3/4” plywood spacer and set up the dado stack with the spacer in the middle and 3/8” cutters on either side. That way, your first cut will give you the exact width of the full dado. For the second cut, you can then simply hog out the middle with the full dado stack. I think this approach would be much less finicky and error-prone, since you only need to dial in your setup for the first cut and can do the second cut by eye.
This is what CNC machines are for.
A big CNC would do this job easily and is the safest option. You could cut up to 10 pieces at a time that way.
The value proposition will depend on the number of cuts per piece and the degree of precision required. More cuts, smaller pieces and higher precision favour the CNC option. Single cuts or one cut at each end of the piece favour using two passes with a dado stack.
I have a triple wing 1-1/2" router bit I use to cut bridle mortises in 4x4s for bench legs. Only advice I can offer if you do this is be patient. It takes more than 1 pass. Be sure your workpiece is very, very secure also.
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