Unsupported Precision Round Rail Calculator

[Jonathan]

Right I've worked out I for the 20mm supported rails in both directions.
In X direction I=53643mm^4
In Y direction I=22257mm^4

To account for the two materials used in the rails I've just scaled I for the bar by 67/200 so if you enter the above values and select steeel in the spreadsheets in this thread it should work.

For comparison the 20mm unsupported rail is 7854mm^4 - so it's roughly 2.8 to 6.8 times weaker than supported rail which is just 'floating'.

(I'm fairly confident that these values are correct, though I've literally only learnt about moments of inertia in the past 2 hours and it's like 1am so no guarantees!)