Archive for the ‘Thread dies’ Category

postheadericon Pre-checks In Using Thread Taps And Thread Dies

Thread taps and thread dies are the main tools used in the manufacture of threaded parts. You have to possess the right knowledge and skills in their proper use, however, especially when the threaded parts are used in precision equipment.

These pre-check procedures are essential in ensuring that the internal and external threads are made according to the specifications.

Determine the Thread Size

There are several thread sizes used in the industry. The metric threads are the most commonly used because of their uniformity with the rest of metric-using world. These sizes include M4, M4, M5, M6, M8, M10 and M12, all of which can be made using standard thread taps and thread dies.

For example, M4 is considered as the standard M4 thread size. This means that, in a bolt, the outside of the thread has a 4mm diameter measurement while the pitch (i.e., the spacing between threads) is at 0.70mm. The other measurements have 5mm for M5, 6mm for M8, and so on.

But emphasis must be made that there are also non-standard metric thread forms. Since these have different pitches, these are incompatible with the standard metric thread forms.

Let’s take, for example, M4 x 0.5mm. You will hear others call it “M4 fine”. Just beware that the term can also be used for threaded parts with M4 pitch less than 0.70mm.

Also, you have to be careful about going smaller than M4. This is because the taps can easily be broken on the work piece – and that’s a bad thing, too, considering that taps are harder than drill bits. You may already have ruined your work piece.

You have to be consistent about the measurements in view of the fact that there are several alternative threads aside from metric threads. You can choose from UK imperial threads, Model Engineer threads, pipe threads, British Association threads, and special Cycle threads. Metric threads are the most commonly used.

Determine the Correct Hole Size

Your next step is to find out the appropriate hole size for drilling. If you’re using the metric system, the standard metric tapping drill sizes are as follows:

  • M4 (x0.70mm pitch) – 3.3mm
  • M5 (x0.80mm pitch) – 4.2mm
  • M6 (x1.00mm pitch) – 5.0mm
  • M8 (x1.25mm pitch) – 6.8mm
  • M10 (x1.50mm pitch) – 8.5mm
  • M12 (x1.75mm pitch) – 10.2mm

You will also find non-metric tables for the same purpose.

Once you have performed these pre-checks, you can start using the tap threads and tap dies to make internal and external threaded holes. As a beginner, you may have difficulty in making these threaded holes but with practice, you will get it right.  Just be sure to make accurate measurements, perhaps even adopt the carpenter’s adage – measure twice and cut once.