Can you specify an engraving depth?

I plan to make some things that are box like in nature. For some of these projects, I want to have hidden joints, rather than the common interlocking joints that are visible on the edges.

With a given material, can you specify an engrave depth? Or is it simply experimentation with different power settings to try to find what works?

For example, lets say I engrave holes around the perimeter of a box base into which the sides will be “plugged”… For the box sides, I would cut the walls out of a 3/8" thick piece of wood in the shape as shown in TOP View. I would then want to shave down 1/8" or so off each of the tabs, so they would appear as in FRONT and SIDE views below. The size and placement of each tab would align with the engraved holes in the base so no joints will be visible on any side of the box. Is this easily doable?

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You cannot specify depth. Yet. This might be something they can work out on really consistent materials and with the aid of the depth sensor, but it sounds like it’ll take a lot of trial and error and once it is working a lot of passes to get correct.

I think it’s doable but something like a CNC router is much more suited to a task like this.

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Definitely experimentation. But when you have the settings dialed in for a given material you should be able to repeat results. It might be easier to engrave a dado and then glue the joint.

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Thanks, @takitus and @markwarfel . That’s what I thought. Hopefully, there will be less trial and error needed on this in the future.

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Given the shape you are looking for, a plain old router (or even a table saw) plus the Glowforge would make quick work of that job. Just reduce the thickness of the entire edge in one pass, and then cut your tabs.

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If you dont have a table saw or router, you can cut the joint on the laser then use a very sharp chisel or a thin backsaw blade to reduce the thickness.

Cutting the receiving side is the tricky part though. I think you could easily mark the square hole locations with the laser but you’ll still need a chisel to make sharp corners.

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I missed the bit about the engraved holes to receive the tabs.
That is trickier, for sure. But… you only need the holes to be deep enough to clear the tabs but not so deep as to go all the way through. You can probably get away with multiple engrave passes even if the depth is not super accurate.

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@cynd11 had excellent results creating a jig and cutting mitered corners…that might be quicker than trying to do multiple engraves if the sides are small enough:

As an alternative, I’ve had good luck with creating an inner box that you glue an exterior facing to…it hides the box joint corners very nicely and gives a finished look.

Or if you use Walnut, the box joints actually look very nice.

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I have through testing been able to get very consistent results for going to a certain depth with Proofgrade. My stamp box has tabs that slide into each other. I go for 1/2 the depth of the material and they even up very well.

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You could cut two pieces, one with holes and one without, and then glue them together to get holes the depth of a piece of material.

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Have you looked at the votive project video? The cutting is through the base board but the tabs do not fit all the way through. maybe you can use something like that?

Care to share any of your settings for doing the 1/2 depth on proofgrade? That is exactly what I am looking to do on the thick maple plywood…

It’s kind of a balance with speed and power and number of passes because the char buildup can lead to non-desirable results. I think I do 700 speed and 60% power and three passes. Cherry, maple and walnut all behave slightly different so you need to test them. The best thing is to get a small test square and use that to see how it works. Start with two passes and see how that works.

I use this as a test file.
DepthTestSquares

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