What is CNC technology? Why is its process so difficult?

May 20, 2026 by MyHiddenBlade

This hidden blade allows you to clearly understand: The difficulty of CNC machining is never in "making it", but in "making it well, smoothly, and stably".

                                                                                                                                                                                                                                                                                                                       

1. What is CNC Machining?

CNC stands for Computer Numerical Control. Simply put: you draw a 3D design on a computer, set parameters such as tool paths, spindle speed, and feed rate for the machine, and the machine uses milling cutters, drills, and other tools to gradually "carve" a block of metal (aluminum alloy in this case) into the desired shape. Its biggest feature is the ability to achieve extremely high precision (errors can be controlled between 0.01-0.1mm) and produce identical parts in batches. It is one of the most commonly used processing methods for figures, models, and industrial parts.

2. Where Exactly Are the CNC Difficulties of This Hidden Blade?

  • Tolerance Control for Multi-Part Fit
     
    The hidden blade is not a single part, but a linkage mechanism composed of more than a dozen components. The gap between the blade and the chute, the fit between the gear and the shaft, and the engagement between the spring and the plectrum all require each part's dimensions to be accurate within 0.02mm. If the width of the chute is 0.1mm too large, the blade will shake; if the gear pitch is slightly off, the traction mechanism will jam. This requires repeated verification at every step from design drawing to CNC programming, and even modifying program parameters based on trial parts.
     
  • Machining of Complex Curves and Details
     
    The dragon pattern carving at the end of the blade, the gear teeth, and the inclined surfaces of the locking parts are not simple planes or round holes. These complex shapes require multiple passes of milling with different diameter cutters. Especially the dragon head shape on the blade, which needs both smooth lines and structural strength, requires repeated adjustment of tool paths during programming to avoid over-cutting and residual material, and many details even require manual polishing and finishing after machining.
     
  • Process Adaptation for Surface Treatments
     
    The blades in the photos have different textures: matte silver, mirror polish, and brass oxidation effects. Different surface treatments also impose different requirements on CNC machining. For example, mirror-polished parts must be machined without tool marks to achieve a good effect in subsequent polishing; parts for brass oxidation need controlled surface roughness during machining to ensure uniform adhesion of the oxide layer. This is not as simple as "processing first then treating", and requires considering in advance during programming.
     
  • Iterative Trial and Error Costs
     
    In the past six months, we have conducted countless trial runs. Every design modification requires re-programming, material preparation, machining, assembly, and testing, followed by problem identification and revision. Every cut in CNC machining consumes materials and time, and this process of "trial-error-modify-retry" is the most exhausting part of the craftsmanship difficulty.

                                                                                                                                                                                                                                                                                                                    

III. To All Who Love "Turning Passion into Reality"

 
This hidden blade is not a mass-produced industrial product, but a work forged from half a year of passion for Assassin's Creed through CNC craftsmanship. It has no fancy packaging, but contains the most simple craftsmanship: from a drawing to a complete mechanical structure, and then to a fully functional finished product that opens and closes smoothly, every detail embodies the pursuit of "restoration" and "precision".
 
Many people ask me, "Isn't it just a model? Is it worth all this trouble?"
 
For us, it is not just a model. When you watch the CNC machine gradually carve the metal into the shape on the drawing, when you assemble the parts one by one, and the blade pops out smoothly the first time you press the mechanism, the sense of accomplishment of turning "something from the two-dimensional world" into reality is irreplaceable.
 
This is the charm of CNC craftsmanship, and also the romance of handmade models: the machine takes care of precision, while I take care of carving passion into metal, cut by cut.