Sienci Labs AltMill 4x8 vs Sienci Labs AltMill MK2 4x4
Two desktop CNC routers side by side, from each maker's own page, read 1 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 AltMill MK2 4x4 is listed $7,230 lower ($3,160.00* against $10,390.00*).
- Sienci Labs AltMill 4x8 has the larger published X × Y work area: 1265 × 2640 mm against 1245 × 1245 mm (2.2× the area).
- Sienci Labs AltMill 4x8 lists more Z: 210 mm against 140 mm.
- Drive: Sienci Labs AltMill 4x8 has mixed drive; Sienci Labs AltMill MK2 4x4 has ballscrew drive.
- Published footprints: 1,676 × 2,896 mm against 1,499 × 1,575 mm.
- Ready to cut (machine plus the cheapest sourced router or spindle, before bits): $11,315 against $4,085.
Published specs
| Sienci Labs AltMill 4x8 | Sienci Labs AltMill MK2 4x4 | |
|---|---|---|
| Price | $10,390.00* | $3,160.00* |
| Work area | 1265 × 2640 mm | 1245 × 1245 mm |
| Z | 210 mm (8.3") | 140 mm (5.5") |
| Spindle or router | Not included | 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. |
| Drive | Rack and pinion on Y; ballscrews on X and Z | Ballscrews on all axes |
| Linear guides | 15 mm linear rails | HGR15 linear guides on all axes |
| Controller and motors | SLB-Ext, grblHAL. Closed-loop NEMA 23 steppers. | SLB-EXT controller with e-stop. Closed-loop steppers; "over 600IPM". |
| Software | gSender | Not published |
| Footprint | About 66" x 114" | 59″ wide × 62″ deep |
| Weight | 400 lb assembled (see spec notes) | 76 lb |
| Warranty | 365 days | 120 days from receipt |
| Spec notes | 3 | 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 46 pairs.