# Maximum material thickness math doesn't line up. How do I target 2" thick?

I’ve recently started looking into making various jigs to use instead of the crumb tray, but am running into one very big (pun intended) scenario where the math just doesn’t line up.

The glowforge FAQ clearly states “there’s a tray for materials that are up to 0.5” thick, or the tray can be removed to accommodate materials up to 2” thick” (described as 50mm on another set of official specs). My crumb tray is 1.36" thick (give or take .04" depending on which corner you measure it), and that seems to be roughly in line with that of other people. As we all should know by now, GFUI limits us to 0.5" material height and focus distance. This gives a total thickness noticeably less than the promised 2"/50mm.

Given that the official specs say that I can work with materials up to 2" thick if I remove the crumb tray, how exactly do I do that?

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Removal of the tray will allow upto just shy of 2(ish) inches. I engrave all my cutting boards which are usually around 1.25-1.5" thick. Whatever the thickness is, I’ll subtract that from the 1.36 (tray thickness) and enter that number in the software as my thickness. This way, the forge is looking at the distance from the top of the tray (that was taken out) to the surface of the item being engraved.

Many times, I’ll engrave something thicker then 1/2" but thinner then 1.36". In this case, I have several 1/8 in and 1/4" circles left over from a project that I use to lift things off the bottom surface until they are combined to a thickness of more then 1.36. Then take the difference and use that number for the thickness.

I hope all this makes sense. I do tend to ramble, and I hope I was clear in my explanation.

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Yes, take out the crumb tray. You can space up whatever you are cutting with shims to get the target cut to be in that 0-1/2" sweet spot. Some people have made custom spacers for this. Search for a post on this subject. There’s a simple math formula that was developed to get the proper focus height settings.

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Understand your question. I measure my tray in the 1.4" range. +0.5" is 1.9". You can’t really get something at 2" and be perfectly in focus. You can get material 2" thick under the head and air assist fan, and give it a slightly incorrect focus for engraving. Engraving off focus is not anywhere near as critical as cutting where the focus needs to be more precise.

But you already understand the math and so no, a full 2" doesn’t work.

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It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email support@glowforge.com.