Ballscrew v Lead Screw for Small Printer

I am planning out a printer, probably corexy, that will be built around a 150mm to 200mm square bed.

I have seen some nice, unused, shortish ballscrews on eBay at attractive prices.

There are some 16mm diameter Hiwins, for example.

There was conflicting advice in prior posts, so I am reasking.

I am assuming the ballscrew will be straighter and more rigid, and can be moved faster.

Since the build is small, I was hoping to get the simplicity advantages of a cantilevered bed, using the screw and a linear rail. At the prices, going with two would be fine, if there is a performance advantage.

There will be more rotational mass, but I was thinking that the small moment makes that a secondary issue.

Any thoughts?

Ball screw lead may not be appropriate for Z axis...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

1605 — 16mm diameter, 5mm lead — is common. So is 1204 — 12mm diameter, 4mm lead. 4mm lead is the same as two-start trapezoidal. I know quad-start 8mm lead and single-start 2mm lead are the most common options, but 4mm is fine too.

Quote
the_digital_dentist
Ball screw lead may not be appropriate for Z axis...

I saw references to people using ~3:1 cog diameter ratios, to overcome some of the potential lead issues, but I am not sure where the limits lie.

Assuming the lead works, any downsides to the ballscrew?

Edited 2 time(s). Last edit at 03/25/2020 11:42PM by Doppler9000.

Quote
mcdanlj
1605 — 16mm diameter, 5mm lead — is common. So is 1204 — 12mm diameter, 4mm lead. 4mm lead is the same as two-start trapezoidal. I know quad-start 8mm lead and single-start 2mm lead are the most common options, but 4mm is fine too.

With a 5mm lead, a 200 steps/revolution stepper gives 0.025mm/turn in full steps, 0.00156mm/turn @ 1/16 microsteps.

Obvious any gear ratio could make these smaller.

I assume this is enough resolution for Z movements?