So i have been reading a lot in the meanwhile.

I found this calculator for critical speed.

https://www.zappautomation.co.uk/ind...culators.html#
And for comparison
http://www.thomsonbsa.com/pdf/bsa_en...og_section.pdf


With about 1500 mm between the bearings, (long axis),
And about 900 mm between the bearings, (short axis),

SFU 1610 @ +/- 1500 mm (+/- 10mm core dia* = +/- 500RPM max * 10mm pitch) = 5 mtr/min
SFU 2010 @ +/- 1500 mm (+/- 15mm core dia* = +/- 800RPM max * 10mm pitch) = 8 mtr/min

SFU 1610 @ +/- 900 mm (+/- 10mm core dia* = +/- 1400RPM * 10mm pitch) = 14 mtr/min



It looks like 2010 is a good investment for the Long axis

I made a redisign of the frame to trade off some stiffness and complexity of the gantry vs frame.

Ill post soon since steel is on the way :-)