# Inverted Thickness - Don't Waste the Waste Board

Note: “Don’t waste” means to not use more than needed or to excess. It does not mean “leave untouched”. Refer to a dictionary on the word “waste”.

I’ve found that I can get much more consistent and less damaging cuts by setting the waste board as zero and then cutting down to it from the height of the piece in the machine. In this case the worst thing that can happen is I get a few air cuts in the beginning. For the alternative, setting the workpiece surface as zero, I can end up cutting up my waste board faster than I’d like or not cutting all the way through the piece.

This essentially moves any errors in my height measurement to be absorbed by either the safe move height buffer (and the first cut) or the air above my workpiece. I prefer this to errors showing up on my waste board or in a piece not being cut all the way through. Additionally, with the waste board zero method, any height errors show up during the very first cut. For the workpiece zero, any height errors show up on the last cuts.

For example, let’s say I have a piece that I think is 15 mm thick, so I enter that for my Z dimension in Easel. I might be wrong either way though, so let’s examine what happens if the material is actually 16 mm or 14 mm for the workpiece zero case and the waste board zero case. Note that in either case the machine can get to zero without error.

A - Workpiece surface is zero, workpiece thickness is actually -1 mm.
B - Workpiece surface is zero, workpiece thickness is actually +1 mm.
C - Waste board surface is zero, workpiece thickness is actually -1 mm.
D - Waste board surface is zero, workpiece thickness is actually +1 mm.

A - The workpiece is thinner than I thought, I cut through it by one mm, damaging my waste board.
B - The workpiece is thicker than I thought, the machine doesn’t cut all the way through the piece.
C - The workpiece is thinner than I thought, I cut one mm shallower than planned.
D - The workpiece is thicker than I thought, my safe move distance is one mm closer and my first cut is one mm deeper.

Note that the second method has the additional benefit of always cutting exactly through the piece.

All this would require is adding the material thickness to all the Z values traditionally calculated. Everything else works the same.

Perhaps a check box in the advanced options could perform this simple operation on all the Z values. I imagine this would be especially desirable for people who paid for the fancy Inventables waste board and don’t want to destroy it rapidly. Wrong place for this, apparently.

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I’m with @PhilJohnson I’ll use the waste board as a waste board

I’m making signs and do-dads not machine parts.

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It’s a bit more complex I think. Because you can not place your bit in the corner and at the waist board at the same time. But I am definantly in Bills camp. My F360 tool paths are set up with the origin at the waist board and getting depths correct is easer and more consistent for me. Especially tabs. It would be a great advanced option for easel.

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yup a waste board is there to waste
everything else is just overcomplicating things.

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How would you zero it like that? I understand putting the z to the wasteboard but then you wanna get the x and y on top of the material being cut.

I haven’t done much programming recently but even if it wasn’t added in Easel i think you could export the gcode, run it through a program that adds XX value to all the z movements and then send that new gcode. Not quite as easy as clicking a box but it’s one way to do it.

You wouldn’t be able to zero the X and Y axis at the same time as the Z. Along with adding the check box, the confirm zero sequence would have to be different… ie: zero bit into wasteboard, confirm Z zero, jog bit to XY zero on top of material, confirm XY zero. Right or am I missing something?

It wouldn’t be a bad feature to have. Maybe in advance setting where it wasn’t easy for someone just learning trying to figure out if they’re supposed to select the conventional zeroing or this method. I would probably try it but don’t know if I would use it all the time.

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1. as mentioned before, a cut is much cleaner when overcut as opposed to just going the exact Z-depth. Adding stock underneath renders your whole point moot. This is important for plywood and ‘fibery’ woods to counter tearout.
2. These machines are not super rigid, especially on larger travel. Therefor, I have found through experience that a cut will not always keep perfect Z-depth, depending on maybe a harder piece of wood it has to dig through. Even with perfectly trimmed wasteboard. So cutting deeper is a must.
3. set zero to top of stockbox is just easier to understand for newcomers to the hobby.
4. Even if & when supported by easel, not all other software supports it. So you’d need to change workflow depending on the software you use. And yes I use different software for different types of work.
5. having gcode with both types of Z alignment is just asking for making mistakes and burying your tool into the wasteboard.

Look it is not the worst idea in the world, but nor is it the best. you are not the first to come up with it, so there’s no need to get cocky about it. It sounds good in theory, but there’s a reason it is not the industry standard.

Do I see a use for the feature? Yes, as a matter of fact I am currently using this method for something I am working on right now, albeit for totally different reasons than the ones you describe. Note that it is a 3D cut, so wouldn’t be possible in easel anyway. So yeah having the choice couldn’t hurt,but there’s no need to push your opinion onto others.

I suggest you try out some CAM package that supports it and test it out for yourself. You’ll soon notice it’s not the holy grail you now so vigurously defend it to be.

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I use the ‘set zero to the surface of the waste board’ method with CamBam and it works well. The first pass can end up being a bit deeper than planned if your material measurement is off. Setting it up this way in CamBam is easy, no extra work required, so I use it.

I plan on trying out F-Engrave which I’ll set up in he ‘traditional’ way if only because that’s how the tutorials do it.

I spent a lot of time setting up a sacrificial spoilboard so I certainly don’t have any issues with cutting into when required.

Whatever method works for you and is easiest to set up.

It’s seems Angus always needs to comment on something.
Or complain about how difficult shipping and receiving packages is due to his location.

Normally I don’t comment on threads that get silly like this one…but here goes.

There are benefits to zero off of the wasteboard in certain situations.

The one that pops to mind, which I have done, is when I am doing a 3D carving and I am milling the entire surface off of the material and when I change bits I no longer have the original surface of the workpiece to reference.

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This is a totally valid request. I know I would like to see it as an option, just because it doesn’t fit someone elses work flow, doesn’t mean its not useful. @ErikJenkins brings up a good point, and off the top of my head it would be usefully for drag knife operations.

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that is exactly the process I was referring to. But even then it didn’t hold up, I use a 8mm ballnose so i set my zero to -4. If that makes sense…
anyway it did what it was supposed to after that.

It was never supposed to be a competition to win or lose. I was attempting to contribute an idea to the community, not argue about out of context aspects of my post with trolls. I’ve deleted this because I am no longer interested in contributing anything to this community. If that’s a ‘win’ for you, then enjoy whatever pleasure that brings you.

If you read any of my posts you would know that what I was claiming was significantly reducing damage to the waste board. Similar to what you yourself were saying in this post.

The replies to my posts were the only ones adding phrases like a “‘Don’t Damage Spoilboard’ check-button”, that this method is a “holy grail” or a “magical zeroing technique”, or only needed because I “can’t be bothered to measure [my] workpiece properly”.

You post right before this is the only time you mention that you took the title as some kind of promise to not put a single mark on your waste board. That’s so clearly not possible, as you say a perfect world scenario, that I can’t imagine I would have even needed to say so. “Don’t waste” does not mean “Don’t touch” it means “don’t make waste of”, “to use sparingly”, or “to preserve as much as possible”. If I said “don’t waste electricity” would you think I meant don’t use any at all? Now replace electricity with “waste board” and suddenly the word waste means “leave pristine”? How does that make any sense? Is that misunderstanding seriously your entire hangup?

I’m obviously not talking about the method, I’m taking about the effect. Is that the only portion of my post you have something to respond with?