CNC EDC Utility Knife – Solid 6061 Aluminum with Swappable Blade

A sleek, ultra-durable Everyday Carry (EDC) utility knife machined from solid 6061 aluminum! Designed to hold standard trapezoid utility blades, this knife features ergonomic finger choils, spine jimping for thumb grip, a lanyard hole, and CNC-milled M3 threads for quick blade swaps.

Credits & Attribution:
This project is a CNC-machined aluminum adaptation of the awesome EDC Utility Knife v14 by @stephenmolvik on MakerWorld, shared and adapted here with his friendly permission! (Note: You can also 3D print the matching sheath from his original project page!)

🛠️ Required Materials & Tools

Hardware & Stock Materials:

Main Body Stock: 6061 Aluminum – 130 x 40 x 8 mm (Tip: You can easily face down a standard 10mm Makera 6061 aluminum plate to 8mm thickness!)
Front Clamp Plate Stock: 6061 Aluminum – min. 60 x 50 x 3 mm
Fasteners: 3x M3 x 6mm Socket Head Cap Screws (or Button Head)
Blade: 1x Standard Trapezoid Utility Blade (box cutter blade)

CNC Tools Required (MakeraCAM Setup):

For the Main Handle Body (Setup 1):

Tool 1 (T1): 4*12mm Flat End Mill (Metal) – Pocketing, Lanyard Hole & Outer Contour
Tool 2 (T2): 3.175*2.5*12mm Drill – Pilot holes for the M3 threads
Tool 3 (T3): 3.175*M3*9mm Thread Mill – CNC thread milling the M3 holes
Tool 4 (T4): 3.175*2.7*12mm Drill – Handle body holes

For the Front Clamp Plate (Setup 2):

Tool 1 (T1): 3.175*12mm Flat End Mill (Metal) – Counterbores, Screw Holes & Outer Contour

🪜 Step-by-Step Guide

Step 1: Prepare the Main Handle Stock (130 x 40 x 8 mm)

If you are starting from a standard 10mm Makera aluminum plate, clamp it down and run a facing operation to mill it down to 8mm thickness.
Secure the 130 x 40 x 8 mm block in your vise or with low-profile clamps on the machine bed.
Probe the Bottom-Left Corner (X0, Y0) and top surface (Z0) using the 3D Touch Probe.

Step 2: Machining the Main Handle Body

Load the Main Body G-Code (130x40x8mm setup). The machine will automatically execute 7 operations:

#1 & #2 – 3D Pocket Roughing (4*12mm Flat End): Mills the recessed seat for the front plate and the precision slot that locks the trapezoid utility blade in place.
#3 – 3D Contour Large Hole (4*12mm Flat End): Helical bores the lanyard hole at the rear of the handle.
#4 – Thread Pilot Drilling (2.5mm Drill): Drills the 3 pilot holes in the blade holder area.
#5 – CNC Thread Milling (M3 Thread Mill): Automatically cuts clean M3 internal threads right on the CNC—no manual hand-tapping required!
#6 – Handle Drilling (2.7mm Drill): Drills the two auxiliary holes in the handle scales.
#7 – Outer 3D Contour (4*12mm Flat End): Cuts out the entire ergonomic handle profile and spine jimping, leaving small Auto Tabs on the outside to hold the part in place.

Here you can see the main knife body being mashined: I glued it down with the CNC tape + superglue method to a aluminum spoilboard i made on the Makera Z1.

Step 3: Machining the Front Blade Clamp Plate (60 x 50 x 3 mm)

Clamp your 3mm aluminum sheet (60 x 50 x 3 mm) flat onto the wasteboard or in the vise.
Load the 3.175*12mm Flat End Mill and probe the stock origin.
Run the Front Plate G-Code (3 operations with a single tool):
- #1 – 3D Pocket Rough: Mills the recessed counterbores so the M3 screw heads sit flush.
- #2 – 3D Contour (Large Hole): Bores the 3 through-holes for the M3 screws.
- #3 – 3D Contour: Cuts the outer perimeter of the clamp plate with Auto Tabs enabled.

Here you can see how I held down the thin plate with Glue underneath and clamps to stabilize.

Step 4: Post-Processing & Finishing

Cut both parts free from the stock frame and file/sand the holding tab remnants flush.
Lightly deburr all outer edges (or soften them with sandpaper / a chamfer bit for a comfortable grip in hand).
(Optional) Glass Bead Blast both aluminum parts! This creates a tough, non-slip matte titanium-style texture that feels incredible in hand and hides fingerprints.

Step 5: Final Assembly

Place a standard trapezoid utility blade into the milled pocket on the main handle body.
Place the 3mm front clamp plate on top.
Insert the three M3 x 6mm screws and tighten them down with a hex key.
(Optional) Head over to @stephenmolvik’s MakerWorld page to 3D print the matching snap-fit blade sheath!