LongMill MK2.5 vs OneFinity Apprentice

Both land on shortlists for buyers weighing a serious hobby CNC. The LongMill MK2.5 runs $1,500 with ACME lead screws (anti-backlash nuts); the OneFinity Apprentice runs $995 with ball screws on all axes (1610 on X/Y, 1004 on Z). Here's how they actually stack up, and who each one is for.

Quick Verdict

Work area decides this one. The Apprentice is cheaper and has the better drive hardware, ball screws against the LongMill's lead screws, but its table is 16.5x16.5. The LongMill starts at 12x30 and goes up to 48x30, which is a different class of project entirely. If you want to cut signs, cabinet parts, or anything longer than a foot and a half, the Apprentice is out no matter how good its screws are.

Specs, Side by Side

LongMill MK2.5 OneFinity Apprentice
Price $1,500 $995
Status Active Active
Work Area 12" x 30" 16.5×16.5×5.25"
Frame Aluminum extrusion with steel reinforcement All-metal construction with aerospace-grade aluminum gant...
Drive System ACME lead screws Ball screws on all axes
Linear Motion V-wheels on aluminum extrusion rails 30mm diameter hardened steel hollow linear motion shafts ...
Motors NEMA 23 stepper motors NEMA 23 stepper motors, 1.2Nm torque
Controller SuperLongBoard RealTime CNC RTS-1 Open Loop Motion Controller
Spindle User-supplied router or spindle User-supplied 65mm router or spindle
Collet Depends on router/spindle choice Depends on router/spindle choice
Max RPM Depends on router/spindle choice 10,000-30,000
Enclosure None None
Assembly Kit Kit
Software gSender RealTime CNC software

Highlighted rows = the two machines differ. Tap a machine name for the full profile.

The LongMill MK2.5 in This Matchup

Next to the OneFinity Apprentice, the LongMill MK2.5 leads with ACME lead screws and a 12" x 30" work area at $1,500. The LongMill MK2. 5 is the best value proposition in the $1,500-2,000 CNC market.

Community: Beloved in the community. "Best value for money" is the constant refrain.

The OneFinity Apprentice in This Matchup

Next to the LongMill MK2.5, the OneFinity Apprentice leads with ball screws on all axes and a 16.5×16.5×5.25" work area at $995. Best budget option under $1,000. Ball screws at this price point is unprecedented.

Community: Excitement about ball screws at this price. Limited long-term reviews since it's new.

Bottom Line

  • Buy the LongMill MK2.5 if you need real table space, up to 48x30.
  • Buy the OneFinity Apprentice if your projects fit inside 16.5x16.5 and you want ball screws for the lowest price.
  • Still unsure? Run both through the side-by-side comparison tool or the beginner buying guide.

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