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Is it possible to calibrate GC with 12 ft beam

I was a little disappointed with my accuracy near the edges, so I got longer chains and made my top beam wider. Do I need to upgrade to web control, or can I still use ground control? My first effort at getting web control set up was a flop.

Web Control is suggested, it has the more accurate holey calibration method
available, and Ground Control is no longer being updated.

That said, nothing in GC breaks due to having a 12’ top beam either.

David Lang

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as David said, you can do it with groundcontrol. you just need to change the chain length and the extended chain lengths in the settings, so it pays out enough chain to actually connect the sled at the original measuring step.

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I don’t see where I can change the chain length in ground control. I put in the appropriate distance between the motors, but when I calibrate, it still only pays out the amount of chain needed as though there were only 10 ft between the motors. I’ve put 12 ft into the settings and into the dialogue box when calibrating, but it doesn’t change how much chain is extended. Any ideas what I’m missing?

I don’t remember what it’s called, but look for the value 1650 or 1651, replace
it with a value that’s a multiple of 6.35 (2702 is a good starting point)

David Lang

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My Maslow is at a remote workshop so I can’t check settings right now. So please forgive me if I am wrong in the following as I am working from memory:

In Web Control there are two chain length setting under “Advanced Settings”.

  • “Chain Length” default 3360mm. The length of one of your new chains (which should be same). I think you need to add more than 4ft to each chain for a 12ft beam.
  • “Extend Chain Distance” with default 1650mm. If I remember correctly the default setting is not quite right and left my home position too high. I think my stock frame had this set at 1850mm to hit dead center. I think this distance should the diagonal length from one motor to the center of the work area.

Try using the following formula (All measurement in mm by default)

√((Distance Between Motors/2)² + ((Work Area Height/2) + Motor Offset Height)²)

If you have not changed your “Work Area Height” or “Motor Offset Height” then this should be:

Distance Between Motors = 12’ => (12 [ft] x 12 [inch per ft] x 25.4 [mm per inch]) => 3657.6mm

=> √((3657.6/2)² + ((1219.2/2) + 463)²)
=> √((1828.8)² + (609.6 + 463)²)
=> √((1828.8)² + (1072.6)²)
=> √(3344509.44 + 1150470.76)
=> √(4494980.2)
=> 2120.14 mm is your new “Extend Chain Distance”

Let me know if this works.