I have no idea; however, @pauldg123 in on this forum (creator of supergerbil) perhaps he’s willing to come out of hibernation to assist).
1 Like
Hi, there is no mapping between the axis, they are all independent of each other. The mapping is done in the post processor within the CNC software application like F360.
However you need to configure the steps for the rotational axis A and B. Normally the stepper motor is 200 steps and depending on the microsteps setting e.g. 1/8 you need to multiply this to get the software setps e.g. 8 x 200 = 1600 steps for a rotation. The rotational axis is often not direct driven but via a gear or belt. You can mark the chuck and run it around G0 B360 and see if it turns a full 360 degrees. If it is short then increase the $ settings in the firmware e.g. $103 (b Axis) = 400. Or if it overshoots reduce the step settings. Hope this makes sense otherwise let me know and we can follow up via an email.
Cheers, Paul
Now it’s getting interesting.
Thanks for the response. I was off in the Supergerbil firmware and I was seeing both comments and implements for supported and unsupported axis gcode processing so I was having a hard time trying to distinguish whether it was just remapping the Y axis or not. Thanks for clearing that up. I’ll take a stab and writing a post for it for F360
1 Like
Considering that the current alternatives for moving to a 4’x4’ workspace cost ~$4k-5k, I think you may find that quite a few of us would gladly pay a premium for that upgrade.
If the change to move to a 4X4 requires new tooling and significant cost, maybe Luke could explore an internal brace/connector to connect the extrusions and selling extensions as a kit with the brace. Current machines should be able to produce those but we need access to proper size extrusions to extend the work surface.
You know he wants to know if you are willing to accept less precision, accuracy and speed.
I guess that would need to be quantified, maybe the loss in precision/accuracy may be minimal and I’m not sure why the speed would be affected.
Also supply chain management is probably an issue, it’s a lot more cost effective to buy the rails cut in a high quantity than a reduced quantity the difference between 100 and 500 units can be astounding on a per part cost. So if you know what you’d sell, you can figure out what the cost is and if we’d pay for it… and so on…
Some one should just poll the forms with new ideas. " Would you buy this…?" “What would you spend?” The 7 or 8 of us in this thread (that’s metric @RichCournoyer 
) are probably not enough.
1 Like
FWIW, we did a poll on upgrade sizes ages ago:
https://forum.shapeoko.com/viewtopic.php?f=11&t=5652&p=48749
1 Like
Unsurprisingly, it looks like being able to fit half sheets (48x48) and full sheets (48x96) of stock were the most popular choices in that poll.
It’s easy to say that you want something when you don’t know how much it costs.
4 Likes
I’m surprised with the results! half sheet size !!! If people looking for that large machine why they choice a desktop one ! I think it’s not easy to go large For many reasons the main reason indeed will be the cash !
2 Likes
I’d just love to know what the cost for a half sheet would be… my bet is $1500+ for just the rails. I mean don’t get me wrong I made a horrible mistake upgrading to a XL not an XXL, but half a sheet pheewww…
1 Like
@RichCournoyer - perhaps once you’ve mastered that, this could be your next challenge:
https://www.amazon.com/Router-Rotary-Table-Rotational-Self-Centering/dp/B06XSFNKCN
One can only dream…I actually did look at these…but there are a couple of reasons why that will never happen with this design. The belt drive does not have enough braking (magnetic field) strength. Good for light wood and laser work only…and since I cut metal about 90%…it’s not for me. Secondly we just don’t have enough Z clearance…
2 Likes
Just make your Z extender plates extend a bit more!
But I don’t have any easy answers for the lack of retaining power. 
Look at how the 4th axis and height limitations were addressed here.
3 Likes
If you’re only trying to get an additional ~15" of length (to make 48" instead of 33"), you could build a fixture to machine the ends one at a time. You really only need a way to accurately set a stop outside of your travel. I can think of several ways that could be done.