@Shauki i think find good small wheels for octo carriage 
fingerboard wheels :
size of wheel:7.5 mm outer diameter, 4.5 mm heigh
size of bearring: 4mm outer diameter , 1.5mm inner diameter, 2mm height
real issue find M1.5 long bolt. 
@Shauki i think find good small wheels for octo carriage 
fingerboard wheels :
size of wheel:7.5 mm outer diameter, 4.5 mm heigh
size of bearring: 4mm outer diameter , 1.5mm inner diameter, 2mm height
real issue find M1.5 long bolt. 
take an Allen Wrench 1,5 and try to flex short part… i think have sufficient strong for octocarriage.
Wurth no have in catalog…and max i find are M1.6 8mm length in Rc catalogue.
M1.5 does not exist. It’s either M1.6 or M1.4, but i doubt either of those can take any real loads without bending.
I see an currently see small size screw(and think have too, check today) just good for place 1 wheel for octocarriage need 2 or 3 wheels joined. For bending depending all from length/material of screw but it possible surely.
i just ask one time
i love you
hahaha
stock from china 400 bearing wheels 98$ if remeber fine LOL