Sienci Labs AltMill MK2 4x4 vs Sienci Labs LongMill MK3 48x30
Two desktop CNC routers side by side, from each maker's own page, read 1 November 2026 and 3 November 2026. Neither has been tested for this site, so this shows what each maker publishes, not which cuts better.
Where they differ
- Sienci Labs LongMill MK3 48x30 is listed $1,360 lower ($1,800.00* against $3,160.00*).
- Sienci Labs AltMill MK2 4x4 has the larger published X × Y work area: 1245 × 1245 mm against 1245 × 813 mm (1.5× the area).
- Sienci Labs AltMill MK2 4x4 lists more Z: 140 mm against 130 mm.
- Sienci Labs AltMill MK2 4x4 doesn't include one; Sienci Labs LongMill MK3 48x30 doesn't say whether one is included.
- Drive: Sienci Labs AltMill MK2 4x4 has ballscrew drive; Sienci Labs LongMill MK3 48x30 has leadscrew drive.
- Published footprints: 1,499 × 1,575 mm against 1,524 × 1,143 mm.
Published specs
| Sienci Labs AltMill MK2 4x4 | Sienci Labs LongMill MK3 48x30 | |
|---|---|---|
| Price | $3,160.00* | $1,800.00* |
| Work area | 1245 × 1245 mm | 1245 × 813 mm |
| Z | 140 mm (5.5") | 130 mm (5.1") |
| Spindle or router | Not included; standard 80 mm spindle mount only. Optional 1.5 kW and 2.2 kW ER20 spindle kits and a 2.2 kW ATC kit. | Not stated on the pages I read. The spec page says it "Supports both 65mm and 80mm spindles and routers. For 80mm spindles, cutting area will be reduced." |
| Drive | Ballscrews on all axes | T12 lead screws on all X, Y, Z axes |
| Linear guides | HGR15 linear guides on all axes | 15 mm profiled linear guide rails and bearing blocks, all axes |
| Controller and motors | SLB-EXT controller with e-stop. Closed-loop steppers; "over 600IPM". | SLB-LITE controller, grblHAL. Closed-loop NEMA 23, 1.2 Nm. |
| Software | Not published | Not published |
| Footprint | 59″ wide × 62″ deep | 60″ x 45″ x 20″ (listed as "Machine Dimensions") |
| Weight | 76 lb | Approximately 80 lb assembled (spec page; not given per size). Shipped in two boxes, 32 lb and 55 lb. |
| Warranty | 120 days from receipt | Not published |
| Spec notes | None found | None found |
| Source | Maker’s page ↗ | Maker’s page ↗ |
Work areas to scale
Open in the compare tool See them on your bench
Why this pair
Pairs are picked by a rule: machines in the same size class and within about 60% of each other's price, plus each machine's nearest sibling from the same maker. No search or keyword data was used. All 47 pairs.