Taps and Dies for Threading

Study Notes

Taps and Dies

Taps are tools that cut threads into a hole, allowing a bolt to be screwed into it.
Taps are typically made of high-speed steel with long channels ground into the sides, leaving gaps in the threads.
These channels allow chips to break free and be ejected as the tap turns into a hole.

Types of Taps

Plug taps: the most common type, suitable for general purposes, with a slight taper, allowing for threading almost to the bottom of a blind hole.
Taper taps: start narrow and then taper to a full thread width, making it easy to start when threading into a hole.
Bottoming taps: for forming threads in the full length of a blind hole, recommended to use a taper or plug tap first to form the initial thread.

Drill Bit Size and Thread Count

For every bolt, there is a corresponding tap of the matching diameter and number of threads per inch.
Similarly, for each tap, there is a corresponding drill bit size that should be used to drill the initial hole.
These relationships can be found on the packaging or through a quick internet search.

Using a Tap

Secure the piece to be tapped using a vise to avoid breaking the tap.
Use a tap wrench to turn the tap, inserting the square end of the tap into the adjustable jaws.
Align the hole directly below or in front of you, and apply slight pressure to the tap while turning the wrench.
After every full turn of the tap, give it a half turn in reverse to break the chips off and clean out the thread.

Dies

A die is the inverse of a tap, cutting threads onto the outside diameter of a rod.
The rod material will dictate which die to use, and the rod should be prepared by filing or grinding a bevel onto the end.
Use a die stock to hold the die securely, and spin the die onto the rod while keeping the rod straight.

Threading with a Die

Align the die with the rod, apply pressure, and turn it onto the rod.
Once the initial threads have been formed, remove pressure and continue turning, remembering to give it a backward turn once every revolution to break the chips.
Test the threaded rod once it has been cut to the desired length.

Description

Learn about taps and dies, including their types, uses, and techniques for threading. Understand how to choose the right drill bit size and thread count for your project. Get hands-on practice with using taps and dies for precise threading.