Why does everybody use the left lower corner as reference? And not the right side?
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I suspect it’s more history than anything.
The axis coordinates are positive moving to the right and forward (away from you in Y), so the bulk of the program coordinates would be positive with the zero in the lower left. But, there’s not much hand written G-code anymore, so this is less relevant today.
It’s perfectly valid to put a zero in the bottom right if you have a need.
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Likely because that is the way the BitZero is setup for. I use center about 95% of the time so I dont use the corners hardly at all.
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Yeah, we’re used to positive X and Y heading right and up.
What is weird is that the machine’s homing “zero” is at the upper right (and up), so Machine Position is always with negative numbers on all three.
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I’ve been curious about that… why center? I’ve not come across a situation where that even makes sense with any of my projects. With my stuff the need is to make sure I have a square corner as I have most often precut the exact size of what I’m carving, so center would be harder to figure out.
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Center is handy when you don’t have a lower left corner, or your stock size is variable.
I have a bunch of cookies, cross sections of a stump/trunk, no flat edges, and not exactly round. It’s easier to mark center than an imaginary lower left corner, and I don’t have to reprogram when the stock size changes.
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My understanding is the reason for the history was right-handed users standing slightly to the left of industrial machines — using lower-left meant that all positive moves were away from the user (to the right, towards the back, up), so that the user in theory only needed to worry about negative moves (left, forward, down) being toward the user and possibly resulting in injury (so long as the user never reached to the right of/behind, or below the tool head).
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See @Tod1d below. As with many things it has become a habit. As said below if things are not in a square/rectangular shape it is handy to use center.
I put a piece of blue tape and mark where I want the center. Usually my material is rectangular so a ruler from corner to corner finds center. Plus I am a turner and use center to help in rounding on the lathe. I use a vee bit to find center or where ever I marked as center and jog down almost touching the surface and then set X and Y. I almost always use bottom of material and then just use rapid positions to get off the project and use the BitZero to set Z zero on the spoilboard.
Engraving on round objects is best in the center because there is no lower right edge.
Here is a bench back that only the end edges were straight with natural slab edges so I figured where I wanted the carving centered and set that as my center. In CC I drew it as a rectangle just big enough for the 6.5" high text and used center.
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Mostly because there is no option to use the right side in Carbide Create. 
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Excellently proven point! As the 80’s commercials used to say, “The more you know”
I am now smarter than I was yesterday 
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I prefer not to customize the look of my bitsetter! 
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Back in the day I typically set zero at the upper left just due to the fact most of the time we using a vice as the fixture of choice. Zero was set against the immovable jaw. All the programs where hand wrote X+ Y-. However, I believe Rob is correct, it was easier to write programs in the positive directions. The software today is fantastic in comparison to what was available in the 80’s. Anyone ever had to type handwritten programs into a teletype to generate punched tape?
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my computer is on the right side. lol thanks for the insight
glad someone else’s brain works some what like mine.
are you a retired fireman? that’s a great answer and something I would of said if the roles where reversed. lol
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you win the internet today with that answer, because I could see myself customizing my bit setter…
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thanks to all for the insight and history lessons.
Re punched tape - sorta the mirror image - in the early 80s I wrote video game clones at Taito NZ to run on Galaxian boards for Taito Brazil.
No internet, so the hex code for patches was output to a tape punch, then the tape sneaker-netted to a telex machine, to cross the Pacific as baudot code.
At the far end some lucky soul got to retype the printout into their eprom burning system.
Re front-left. As school math involved in graphing etc has XY axes with left/low 0s, I would guess that would be the intuitive base for most folk…
Fortunately not a lot of polar-coordinates required…
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This reminds me of the following story that I have heard over the years in various versions:
The Story of the Pot Roast
A young woman was hosting a dinner party for her friends and served a delicious pot roast. One of her friends enjoyed it so much that she asked for the recipe, and the young woman wrote it down for her.
Upon looking over the recipe, her friend inquired, “Why do you cut both ends off the roast before it is prepared and put in the pan?” The young woman replied, “I don’t know. I cut the ends off because I learned this recipe from my mom and that was the way she had always done it.”
Her friend’s question got the young woman thinking and so the next day she called her mom to ask her: “Mom, when we make the pot roast, why do we cut off and discard the ends before we set it in the pan and season it?” Her mom quickly replied, “That is how your grandma always did it and I learned the recipe from her.”
Now the young woman was really curious, so she called her elderly grandma and asked her the same question: “Grandma, I often make the pot roast recipe that I learned from mom and she learned from you. Why do you cut the ends off the roast before you prepare it?”
The grandmother thought for a while, since it had been years since she made the roast herself, and then replied, “I cut them off because the roast was always bigger than the pan I had back then. I had to cut the ends off to make it fit.”
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I learned BASIC in my senor year of high school in 1974 using a teletype terminal, with punched tape for storage. The previous semester I learned FORTRAN, using IBM punched cards for storage (draw that vee on the card stack edge for WHEN you drop it…)
The first GCODE I wrote in about 1989 was 4-axis wire EDM for cutting a mold. A spiral wall with vertical ribs of different sizes, all with draft angles (all mathematically programmed in Visual Basic on a Mac+). I took a floppy disk to the moldmaker, who transferred to punched tape for the EDM machine.
Fun times.
I still have a photocopy of the BASIC printout of the EDM gcode and some day (yeah) would like to render it in some viewable form…
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