Tapping
Threading
External Threading
What is Threading?
• Threading is a process of removing helical turns from the
curved surface of a bar.
• The tools used to create a threaded bar are Dies and
Stocks.
• This process is also known as the male thread.
• To get a good finish we use a technique called Chasing.
• Chasing is when the bar is threaded and we do the
process again to achieve optimal finish.
Threading Process
• There are many types of threading, the method chosen
for one application depends on time, money, degree of
precision and available equipment.
• Threading falls into two general categories, workshop
threading and mass production threading.
• Hand Treading is an example of a workshop threading
process and Rolling is a mass production process.
• Were now going to look at the workshop process of
threading.
Workshop Threading
Hand Threading
• Hand threading is a threading process using a certain
size die and stock to create the external thread.
• The chosen die is placed in the stock and tightened here
using a screw because this die is a Round Adjustable die.
• Hexagon Rethreading: These are precision dies not to be
confused with standard dies, these are used to rethread
damaged or jammed threads are not for creating threads.
• Cone Dies: These are designed for Production Threading
or screw machines and other threading equipment. They
are designed to project from the die holder with a short
die chamfer for close to the shoulder threading.
Threading Process
• Determine the size and depth of the
thread that you want, if the hole is a
M5 then tap the bar M5.
• You can also work the size out by
using the universal drill size chart.
• Mark the length of the bar you want to
thread and clamp it in the vice.
• Taper the top of the bar using a file to
aid the die to get a grip.
• Choose the appropriate Die and Stock for the die. Then
fasten the die in the stock usually with a screw.
• Once the die has a grip apply lubricant for quality finish
and ease of material removal.
• Once the thread is started it is important to clear swarf
to prevent damage or jamming to the piece or die.
• This is done by turning the stock backwards a quarter
rotation for every half rotation forward.
● Continue doing this until you complete the required
length of thread.
● Then back out the die and clear any swarf or Cutting
Fluid.
● If necessary chase the workpiece for optimal result.
How to Draw Threads and Taps
M10
Types of Dies
• There is several different Dies for Different tasks.
• Round Adjustable: This die is the most common and is
used for most common threads.
• Hexagonal Dies: These dies are designed for tough cutting
applications of all types of cutting threads and need their
own stocks.
Lathe Threading
• Making threads in the lathe is similar to using the die
and stock.
• A special Lathe tool is used to create the thread.
• One of the main differences is that it is a continuous chip
removal process which prevents jamming and aids the
lathe remove the helix curve from the surface of the bar.
• The Lathe has to be in the automated mode to ensure a
consistent external thread.
• Threading on the lathe with a stock and die or just a die
is also possible but is not advisable, once you stop and
put the lathe in reverse to prevent jamming it is ok.
• It is important to have the lathe in a very slow gear to
complete this process.