How to Cut a Screw Thread

Screws are created by carving threads into a metal rod.
Screws dig into a surface and create a reliable hold on an object.Screws dig into a surface and create a reliable hold on an object.
Screw threads allow a screw to join two objects together. The threads spiral up the length of the rod and gradually become larger in diameter, which digs deeper into a surface and expands in a way to create a stronger hold. Carving threads in a screw requires proper machinery and a list of standard thread sizes in order to create a screw that will work with any pre-drilled hole.

Step 1

Set the gears on the standard change gear lathe to the size threads you want on the screw. Adjust each setting until they are set to standard guidelines. For a 1/4 inch screw with 24 threads per inch, set the decimal equivalent on the drill to .2090. For example, a 5/16 inch screw with 20 threads per inch, set the decimal equivalent on the drill to .2656.

Step 2

Lock the metal bar into the lathe. Secure it tightly with the grip knob.

Step 3

Turn on the lathe and gently move the cutter bit along the metal rod. The cutter bit will carve away the metal rod and create a thread on the metal rod.

Things You Will Need

  • Standard change gear lathe
  • Cutter bit
  • Metal rod, 1/4 by 3 inches long
  • Goggles

About the Author

Nicole Byerly has been writing since 2003. She has published multiple works that have appeared in "Campus Philly." Byerly is pursuing a Bachelor of Science in cybersecurity at Utica College.