CNC for Small Auto Parts

You’re restoring a car and need a hose fitting that no one makes. You’re building a hot-rod and need a particular shape carburetor adapter plate. Or perhaps, during an engine rebuild you find you’re missing a spacer that fits under a pulley. What do you do?

If you have access to CNC machine tools, you could make what you need. CNC mills, lathes, routers and even plasma cutters are ideal for making a whole range of small auto parts. Whether you’re a hobbyist or run a small machine shop, CNC machines could be a big help with those small auto parts.

A Short CNC Primer

Until the late 1950s/early 1960s a machinist worked a lathe or milling machine by winding a handle or operating a motor to move the cutting tool or workpiece. Then along came Numerical Control with automatic motor control. A little later a computer was added for complete motion control and voilĂ , you had Computer Numerical Control or CNC.

A CNC machine follows a sequence of instructions – a program – to perform a series of machining steps. A lathe might turn hexagonal bar stock into a drilled and threaded hose fitting. An end mill on a vertical milling machine could cut pockets in a solid metal billet to produce a carburetor adapter plate.

There are two ways to create part programs. Short programs are often entered directly at the machine, using a keyboard and screen. Longer, more complex programs are developed offline and then sent to the machine. Offline programming can be done manually or automatically. In manual programming the programmer looks at the drawing and writes a part program. Alternatively, they use Computer-Aided Design/Computer-Aided Manufacturing (CADCAM) software. This takes the CAD file and, usually with some human input, develops the optimal cutter paths.

CNC Benefits

Easy programming and next-to-no set up time mean CNC machines are ideal for small quantity production, even one-offs. They’re also accurate and repeatable. If you’re producing a small batch of parts – valve spring retainers perhaps – you can be confident each one will be the same.

Machining Small Auto Parts

For creating something special – brass hose fittings, stainless steel brackets or one-off caliper adapters – CNC machines are invaluable. They’re fast and accurate, and for small part machining, can be surprisingly compact. Put a mill and a lathe in your garage and you’ve got a small auto parts machine shop!

CNC Machines and Manufactures (Partial List)

  • Baileigh PT-22
  • GMC PT-0510/105A
  • Mophorn Laser Engraving Machine
  • Newlin CNC Gas Oxyfuel Flame
  • Genmitsu CNC Engraving Machine
  • BobsCNC E4
  • CNC 3018 Pro GRBL
  • Go Fab CNC Plasma Table
  • STV Motorsports SparX510
  • BobsCNC E3 CNC
  • AKS Cutting Systems
  • American Torch Tip
  • ARC Cutting Industries
  • Dynatorch
  • ezPlasma
  • GoTorch
  • Hypertherm