I Started my lowrider build on 11 November 2017. I converted the bolt and nuts to the most compatible of the metric system. This worked out very well so far:
BOLT 5_16 x 5 => M8 x 130
BOLT 5_16 x 4 => M8 x 100
BOLT 5_16 x 1.75 => M8 x 45
BOLT 5_16 x 1.25 => M8 x 30
locknut 5_16 => M8
SCREW 6_32 x1 => M4 x 25
SCREW 6_32 x .75 => M4 x 20
LOCK NUT 6_32 => M4
The M3,5 is close to the 6_32, but that is not good available so ended up with M4 and making the holes bigger.
The 1 inch tubes, I found at a custom bikershop in Holland (The Hage).
Cool, very few international LowRider CNC builds.
I have added your conversions to the parts page, thanks for taking the time to share them.
I changed the lead screw for an piece of M8 and redesigned the printed part. This way the Z-axes have less trouble keeping the things in place because the pitch of M8 is lower.
It must be right on the edge, here the 5/16" would not work well. It would bind randomly. The T8’s haven’t failed me so far.