Hey all,
All my parts are printed, electronics and flat parts delivered from Ryan and I just picked up my stainless 1”x0.065 tube. The question is, how straight do I need these tubes to be? There’s a definite bow when placed against a straight edge with the 60” segments. The12” segments lay flat against my surface plate
Put the bow up, and hope gravity helps you out!
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Isn’t it going to affect z-axis accuracy? How much of a bow is it? I’d think if you only use the lowrider to do full depth cuts, it wouldn’t be a huge problem. But if you try to do carvings across with full width of the board, I think you’ll find the center to not cut as deep as the sides.
But also, there are tolerances on every machine. The gantry definitely sinks down on every low rider in the middle, the question is how much. Wood is a natural material and there are limits to the accuracy achievable.
My vote is to either measure it now, or install it and find a way to measure it once the machine is all assembled.
I guess you can use gcode sender that can autolevel the gcode to overcome some of the issues if you do have problems.
Any bend is typically extremely minimal over 4.5’, if gravity does not take care of it I would just lean on it real hard and bend it more straight. Or face them in opposite directions parallel to the table to counter act each other. No need to use software. If it is that bad you should get new rails.
Happy New Years! I Pulled out the thickness gauge, I can slide a 0.8mm shim under the bow in the middle at its worst. The tubes look pretty straight by eye but when put up against a straight edge the issue is more pronounced. I may try to run it like it is maybe when I button everything up it will be fine! Currently assembling the kit fingers crossed.
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My plan is to build this cnc router large enough to handle full sheet goods.
That is what I figured, that is bad but manageable I assume. I know we are making “precision” machines but in reality they can be quite a bit of slop and still wind up with a crazy accurate build. Square is far more important than perfect rails…also why I did not make a full Y axis railed machine, much easier to flatten a table than a rail.
To be honest, I wouldn’t think 0.8mm to be really that bad for anything 5 feet long. That’s ~1/32 inch…
So far so good, center carriage travels freely. I’ll find out if my worrying about the bowed tube was warranted when i try my crown test. First I need to do electronics and build a table for it.
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There was a little bend in my tubes as well, I trued them up by hand as good as I could. Then I ran a leveling program to cut the table “flat” to the machine.
You can also try to “counter act” the bow by putting the bows of the rails in opposition, or like Ryan suggested put the bow up to compensate for any weighted sag.
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My wife would never, ever allow that in our living room.
I’m sure I’ll have to take the machine apart and rework it/tighten fasteners but I think I’ll try it with the bows facing away from each other and oriented horizontally that should hopefully give me the flattest travel.
My wife made the comment today that she doesn’t know who makes a bigger mess me or our 2year old. It’s a pretty even match haha.
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I’d do that, then put a big ass scratch on the table.
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disclaimer: I’ve not finished my build… I think putting the bows opposing in the horizontal might cause binding. @vicious1 recommended putting the bow upwards… they weight of the sled when it reaches the center might bend the pipes downward a little and flatten everything out. Heck, maybe it turns out that 0.8mm bow is desirable. But even if it doesn’t flatten out, I’d rather have less accuracy in the zaxis than in x or y or have binding when the sled moves along the gantry.
I have 4 days off this coming week so hopefully I can get my table built and electronics wired. Dual end stops with auto squaring sounds fun not sure if I’ll try that first though. The router sled slides freely with no binding currently so I think it will be okay.
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