Blog › Leadscrew vs ballscrew: how a CNC router moves
1 November 2026 · 2 min read
Leadscrew vs ballscrew: how a CNC router moves
Two ways of turning a motor's spin into straight-line motion, and which machines in the record use each.
A stepper motor spins. The axes of a CNC router need to move in a straight line. Something has to convert one into the other, and on most desktop routers that something is a screw. Turn the screw and a nut riding on it moves along. Bolt the nut to the axis and the axis moves.
The two kinds of screw you'll see on spec sheets are leadscrews and ballscrews. Carbide 3D's Shapeoko page also mentions belts and gear racks, as the methods its machine doesn't use.
Leadscrew
In a leadscrew the nut's thread slides directly against the screw's thread. Wikipedia's article says leadscrews have "a high degree of friction on the threads", and that "most are self-locking (cannot be back-driven)", meaning a load pushing on the nut won't spin the screw. Carbide 3D lists "anti-backlash nuts on every axis" for the Nomad 3, though it doesn't say what kind of screw they're on.
Ballscrew
In a ballscrew the thread is a groove for steel balls, which roll between the screw and the nut instead of sliding. Wikipedia gives the difference in efficiency: "A typical ball screw may be 90 percent efficient, versus 20 to 25 percent efficiency of an Acme lead screw of equal size." The balls can be preloaded "so that there is no 'wiggle' between the ball screw and ball nut". The same article notes they're "more expensive to manufacture" and "can potentially be back-driven".
Which machines use which
| Machine | Drive | As published | Price |
|---|---|---|---|
| SainSmart 3018-PROVer V2 | Leadscrew | Leadscrew | $219 |
| SainSmart 3020-PRO MAX V2 | Not published | $399 | |
| SainSmart 4040-PRO | Leadscrew | Leadscrew | $599 |
| FoxAlien Masuter Pro | Not published | $600 | |
| FoxAlien Masuter Pro Max 2x2 | Not published | $900 | |
| SainSmart 4040-PRO MAX | Not published | Leadscrew on Y; the page doesn't say what drives X and Z | $949 |
| Onefinity Apprentice | Ballscrew | Ballscrew (1610 on X/Y, 1204 on Z) | $995 |
| FoxAlien Masuter 3S | Not published | T12 leadscrew on Z; the page doesn't say what drives X and Y | $1,000 |
| Sienci Labs LongMill MK3 30x30 | Leadscrew | T12 leadscrews, all axes | $1,400 |
| Onefinity Gen 2 Elite Woodworker | Ballscrew | Ballscrew (1616 on X/Y, 1610 on Z) | $2,195 |
| Carbide 3D Nomad 3 | Not published | $2,800 | |
| Sienci Labs AltMill MK2 4x4 | Ballscrew | Ballscrews on all axes | $3,160 |
| Carbide 3D Shapeoko 5.1 Pro 4x2 | Ballscrew | Ballscrew (16 mm, 20 mm pitch X/Y; 1610 Z) | $3,550 |
| Sienci Labs AltMill MK2 2x4 | Ballscrew | Ballscrews on all axes | $3,890 |
In the record so far, the five ballscrew machines are priced from $995 to $3,890 and the three machines with leadscrews on every axis from $219 to $1,400, so the ranges overlap. Four pages don't say how their machine is driven at all, and two more only describe one or two axes.
Reading the numbers
Ballscrews are often described with a four-digit code. Carbide 3D's pages show what it means: the Shapeoko 5.1 Pro product page calls the Z screw "a 1610 ballscrew", and the spec page gives the same screw as "16mm diameter, 10mm pitch". So Onefinity's "1610" and "1616" screws read the same way. Sienci Labs describes the LongMill's leadscrews as "T12".
A screw's efficiency on paper doesn't tell you how well a machine cuts. Frame stiffness, rails, motors and the controller all matter, and this site doesn't test any of them.
Sources
Read on 1 November 2026. Quotes are copied from these pages.