Image: Sienci Labs
Sienci Labs LongMill MK3 30x30
Sienci Labs
Best for: Hobbyists and small shops who want a well-supported 30x30 inch machine for wood and plastics with occasional aluminium
Typical starting price
$1,400Editorial baseline for this machine
Overall score
Best current buying path
Where to buy
Prices change often: compare the stores below
- Shipping varies by retailer
- Check manufacturer site for availability
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Quick verdict
The LongMill MK3 is Sienci's 2026 redesign of its best-selling benchtop CNC, and the 30x30 is the size most people buy. The important change is the motion system: 15mm profiled linear rails on all three axes and closed-loop NEMA 23 motors replace the MK2's roller wheels and open-loop motors, which should mean noticeably better rigidity and no silent lost steps. Lead screws remain, so it is still a wood and plastics machine first, with aluminium possible at modest feeds. At about $1,400 before a router it undercuts the MK2.5 it replaces while being the better machine on paper.
Who this fits best
Hobbyists and small shops who want a well-supported 30x30 inch machine for wood and plastics with occasional aluminium
Buy this if
Hobbyists and small shops who want a well-supported 30x30 inch machine for wood and plastics with occasional aluminium. Profiled 15mm linear rails on every axis, a big step up from the MK2 roller design.
Skip this if
Router is not included, budget for a trim router or the AutoSpin T1, and lead screws, not ball screws, so long-term wear and speed are below an AltMill.
What else you still need
A 65mm trim router or Sienci's AutoSpin T1, a flat table or bench, an MDF wasteboard, bits and clamps. A dust shoe and shop vacuum are close to essential indoors.
Material reality check
Hardwoods, softwoods, plywood, MDF, plastics and foam are its home ground. Aluminium works with small cutters and light passes; it is not built for regular metal production.
Better alternative if...
you plan to cut aluminium regularly or want ball screws. See Sienci Labs AltMill MK2 2x4
Where it wins
- Profiled 15mm linear rails on every axis, a big step up from the MK2 roller design
- Closed-loop NEMA 23 motors detect lost steps instead of silently ruining a part
- Ships largely pre-assembled, Sienci quotes about two hours to first cut
- Y-axis auto-squaring and limit switches come standard
- Free gSender software and Sienci's documentation are among the best in hobby CNC
Where it falls short
- Router is not included, budget for a trim router or the AutoSpin T1
- Lead screws, not ball screws, so long-term wear and speed are below an AltMill
- No table or wasteboard in the box
- Lead time was about six weeks at launch
- Prices are set in Canadian dollars, so the USD price moves with the exchange rate
Specifications
813 × 813 mm
6610 cm²
710W
65mm trim router mount, router not included (80mm spindles also fit)
SLB-LITE running grblHAL, NEMA 23 closed-loop steppers (1.2 Nm)
33 kg
$1,400
mid range
Full specification table
Relative to database
Benchmark Scores
Overall Score
Composite across 5 dimensions
Community Sentiment
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