Designing machined parts feels straightforward in CAD until the tool hits the material and you get blown-out corners, chattering walls, or a feature the shop politely calls “impossible.” Suddenly your simple bracket needs four setups, a custom fixture, and a machinist who doesn’t hate you.

This guide walks through the fundamentals of CNC-friendly design: tool access, wall thickness, thread choices, fillets, tolerances, and more. Think of it as the “don’t wait for your machinist to send you a spicy email” playbook for anyone who sends parts out to be cut.

CNC (Computer Numerical Control) machining is a manufacturing process where raw material is shaped into a finished part by automated equipment guided by programmed toolpaths. It’s a subtractive method: you start with a solid block of material, known as the workpiece, and remove everything that isn’t the final geometry using precisely controlled cutting actions. If you can hold it securely and reach the features, you can usually machine it.

CNC machining is broadly material-agnostic. Aluminum, steels, brass, titanium, ABS, Delrin, nylon, composites, wood; almost anything can be machined as long as the tooling and cutting parameters are appropriate. At a high level, the workflow follows three steps:

CNC machining is widely used because it delivers high precision, repeatability, and predictable tolerances. The rest of this cheatsheet focuses on practical constraints like how to design for CNC machining, avoid machinist landmines, and get parts that run efficiently in real shops.

CNC machining is a broad family of manufacturing methods built around different machine motions, axis configurations, and cutting strategies. While the technology can be complex, most machined parts come from three core machine types: CNC Mills, which remove material with rotating tools; CNC Lathes, which spin the material while stationary tools cut; & Mill-Turn machines, which combine both approaches in one setup.

The workhorse in most machine shops. Built for prismatic parts shaped by flat faces, pockets, slots, bosses, and controlled 3D surfaces. Adding more axes increases access, which means fewer setups, better tool angles, improved surface finish, and the ability to machine compound features and undercuts that a standard mill can’t reach.

Used for anything rotational that has a primary central axis like shafts, pins, bushings, threaded parts, and sealing surfaces. A traditional lathe cuts with the work piece spinning and…

Most teams struggle in the last mile of go-to-manufacturing. Going from a polished 3D model to a clean, accurate, shop-ready drawing still takes hours of clicking, fixing views, adding GD&T, and chasing down tiny mistakes that slow down production and introduce risk.

Drafter closes that gap. It turns your 3D model into a high-quality, fully detailed engineering drawing in minutes, not hours; complete with proper GD&T, dimensions, and title-block details. You get consistent, manufacturing-ready documentation on the first try, so you can move from design to machining, fabrication, or inspection with confidence and without the usual friction.

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Happy engineering,

The Drafter Team