Image: Sienci Labs
Sienci Labs AltMill MK2 4x4
Sienci Labs
Best for: The serious hobbyist or small shop stepping up from a belt machine who wants industrial motion components without industrial pricing
Typical starting price
$4,290Editorial baseline for this machine
Overall score
Best current buying path
Where to buy
Prices change often: compare the stores below
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- Check manufacturer site for availability
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Quick verdict
The AltMill is the machine that has dominated prosumer CNC conversation for the last two years, and the spec sheet explains why: HGR15 industrial linear rails and ball screws on all three axes, closed-loop steppers with auto-correction, and a grblHAL controller, at a price where competitors still ship V-wheels. Sienci also gives away gSender, which is better than most paid senders. The catch is the spindle is separate, so add 800 to 1500 dollars to the real cost.
Who this fits best
The serious hobbyist or small shop stepping up from a belt machine who wants industrial motion components without industrial pricing
Buy this if
The serious hobbyist or small shop stepping up from a belt machine who wants industrial motion components without industrial pricing. HGR15 industrial linear rails and ball screws on all three axes at this price is unusual.
Skip this if
Spindle is sold separately and adds 800 to 1500 dollars or more, and heavy, and assembly is a real project.
What else you still need
A spindle (800 to 1500 dollars or more), a frame for a heavy machine, dust collection and a few days of assembly.
Material reality check
Wood, sheet goods and aluminium across a full 4 x 4 bed. One of the stiffer options in this size class for metal.
Better alternative if...
you want an automatic tool changer at a lower price. See Genmitsu PRONAX Forge
Where it wins
- HGR15 industrial linear rails and ball screws on all three axes at this price is unusual
- Closed-loop steppers with auto-correction catch lost steps
- gSender is free, actively developed, and genuinely good
- Optional 2.2kW ATC spindle puts automatic tool changing within reach
- Made in Canada with a strong documentation and support culture
Where it falls short
- Spindle is sold separately and adds 800 to 1500 dollars or more
- Heavy, and assembly is a real project
- Two to three week lead time
- grblHAL is more capable than GRBL but less plug-and-play than a Masso or Centroid
- Machine-only pricing makes direct comparison with all-in machines misleading
Specifications
1245 × 1245 mm
15500 cm²
2200W
80mm mount, spindle sold separately: 1.5kW, 2.2kW or 2.2kW with ATC
SLB-EXT running grblHAL, with closed-loop steppers and auto-correction
110 kg
$4,290
premium
Full specification table
Relative to database
Benchmark Scores
Overall Score
Composite across 5 dimensions
Community Sentiment
We have not summarised owner feedback for the Sienci Labs AltMill MK2 4x4 yet, so this section is intentionally left without claims. Check the sources for current owner discussions.
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