Some time ago we published a blog entitled, "CUTTING TAP CHAMFER 101”. It described what the chamfer’s purpose is, and what standard lengths are offered on off the shelf taps. They are Bottoming, Plug, and Taper. This blog builds on that information and goes into more depth so you can optimize the chamfer based on your application. Although we stock many common special taps with standard chamfer lengths, we can design and manufacture a special tap for your application. Optimizing the chamfer results in, longer tap life, reduced tapping torque, better finish, and make the difference
Ever wonder what the difference is between an NPT (National Pipe Taper) and NPTF (National Pipe Taper Fuel) threads are? It’s not just the spelling.
They are both the same in many ways,
- both are used to carry fluids and gasses
- both have the same diameter, thread per inch combination, sizes, 1/16-27, 1/8-27, ¼-18, etc.
- both have an included thread angle of 60 degrees.
- both have a thread that tapers 3/4 per inch per foot or 1/16 per inch.
- both have flatted crest and roots
- both have the same pitch
If a tap doesn’t create the hole, why is the hole size so important?
As an experienced machinist will tell you, threading holes is the last thing you master in this craft. Why is that so?
1. Drilling and milling are usually easier.
2. Threading the hole is usually the last operation on a part.
Let's look at one variable: Hole size.
Generally, for 60 degree threads, the percentage of thread should be 75% as a rule-of-thumb. That seems to be a good guideline, as it falls within both 3B and 2B minor diameter
In the beginning, machining was less complicated, at least it seems that way from present day point of view. Material available for use was found on a much shorter list. Options for machinery and tooling were more limited. Coolants and lubricants were literally water and oil.
Today, we are presented with nearly unlimited options in the machining process. Tooling has improved, so have available coolants and lubricants. Engineers and designers are willing to stretch the limits of what is possible. Manufacturing is left to produce a part that matches the specifications of the print. A