Gandalf

Acme

110vdc 500w motor ($55) with a 10TPI acme thread should be able to accelerate pretty fast. The range seems to be 3000-10000rpm, so I'm not sure how fast it will actually go. But at full speed, even 3000rpm is 5"/s.

I found one motor on Ali Express for just over $30 that's 1300rpm, about 20rps. At 10TPI, that's 2"/s, too slow. It should be about 5 times faster, but that could be accomplished with gears.

I found a 500w 24V motor (so a power supply would be required), 2500rpm, about 4"/s, still too slow, but less gearing required.

A 190w 24V 10Krpm motor for $70. Maybe.

A 60W 24V 10Krpm only costs about $14, that might be plenty. The acme screw would provide a lot of gain.

I've also seen 4Nm 48v steppers for around $40, that might work.

Drill Motor

• motor: $14
• leadscrew: $15
• psu: $13

Stepper + Belt

A lead screw requires a high rpm, which rules out a stepper, which makes speed control difficult. There will be very low power at low speeds. I think a stepper connected to a belt will work better.

Steppers

• $20 Nema23 1.9Nm
• $60 Nema34 4.5Nm

The Nema34 is rated at 5.5A, but I can only find drivers up to 4A. It looks like 3.1Nm are kind of common.

Parts

• 3.1Nm motor $40
• Driver $10
• Belt+Pully: $8