LongMill MK3
Sienci’s 2026 redesign of the LongMill: linear rails on every axis, closed-loop motors and a mostly pre-assembled frame.
If you’re buying your first real CNC, start here.
The LongMill has been the friendly first machine for years, and the MK3 fixes the thing people complained about: the V-wheels are gone, replaced by profile linear rails on every axis. Add closed-loop steppers, auto-squaring Y and a controller running grblHAL, and you have a lot of machine for $1,400.
It’s still lead screws, not ball screws, and you’ll need your own trim router. But Sienci’s documentation, free gSender software and community are the most welcoming in the hobby. If someone asks me where to start, this is the answer most of the time.
— Will
What I like
- Linear rails on all axes at this price
- Closed-loop motors and auto-squaring
- Open-source grblHAL and gSender
- About an hour to assemble
What I'd watch for
- Lead screws, not ball screws
- Router not included
- New platform, still building a track record
| Work area (X × Y × Z) | 813 × 813 × 130 mm 32.0 × 32.0 × 5.1 in |
|---|---|
| Spindle | Bring your own — 65 mm trim router |
| Drive | Lead screw (T12, anti-backlash) |
| Linear motion | 15 mm linear rails |
| Frame | Aluminum & steel |
| Enclosure | No |
| Tool changer | Manual |
|---|---|
| Controller | SLB-LITE (grblHAL), closed-loop |
| Software | gSender (free) |
| Metal | Light aluminum, slowly |
| Footprint | — |
| Released | 2026 |
Still confirming with Sienci Labs: price (from US reseller listing).