As I delve into a deeper level of training, can someone tell me the laser beam tolerance of the Glowforge?
You mean tolerance in what way? Are you asking the thickness of the beam? Power output? X/Y positioning?
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Going to guess you mean the width of the cut (kerf). It will vary wildly with the material, power and speed. Only experience will give you the answer or someone who has already experimented with exactly your material and intended purpose.
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Yes, thickness of the beam.
Hmmm…I did not realize that the width varied. Guess as a saw-blade-kinda woodworker, the kerf is always the saw (well, excusing an unbalanced blade).
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same
The beam converges to create a spot, which will be the smallest point. The spot is about .008”. Above and below that focal point, the beam will spread.
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The spot has a Gaussian power distribution, so it is hard to say what the diameter is. There are lots of definitions and a common one is the diameter where it drops to half power. So if that definitions gives 0.008" there is still some power outside of that. That is partly why you get a kerf that depends on how fast you move. At high speed the outer parts of the beam don’t deliver enough energy to ablate material but at a lower speed they might do.
So the sort answer is the kerf depends on the material, the power and the speed.
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If it is super critical I will cut a 1" x 1" square using the material and speeds I will be using for the project. Then measure that square, subtract that number from 1, this gives you the total cut width, divide by 2 to get your offset. if its not that critical I will offset my cut by .006" and thats pretty close.
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I’ve always assumed the thermal properties of the material also come into play, yeah?
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Yes the conductivity, specific heat capacity and the temperature threshold at which the material ablates all have an effect.
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That all jives with what I’ve observed. the material that I seem to get the smallest kerfs is cardboard, it’s razor thin.
The worst are the really difficult to cut tropicals, rosewood, 1/4" thick sapele, Ipe. You just gotta beat on them so hard that the kerf gets huge. The Ipe is close to half inch, took 9 pro full power passes at about 200 speed to get through it. Tough stuff, and a very sloped cut profile as a result.
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Thanks all. Since critically is NOT an issue, .006-.008 is sufficient knowledge.
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Not that we didn’t want to give a number range, but there are mathmaticians here. Approximation is not always understood. 
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As a physical scientist working in nuclear technology, oh how I appreciated the technical discourse. I was a little rushed so excuse me if I appeared brief.
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Thanks for letting us know you got the help you needed, @rmelvin06 . Thank you all for the discussion and help!