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
Tap Drill Size for NPT and NPTF Taper Threads
You got the job. You ordered and received material. You ordered and received taps and gages from North American Tool. The job is now out in the shop to be manufactured and the first operation is to produce a hole before tapping. How do you determine what tooling to do that with?
Holes before tapping pipe threads are produced either straight or tapered. The choice of method is
Have you ever had a tapping job that was so troublesome that it caused heartburn or acid indigestion due to broken taps, bad finish, short tap life, over or undersized threads, ETC.?
One way of avoiding or alleviating such a condition is accomplished with the use of a tap feature called “relief”. The definition of “relief” according to Marian Webster, is removal or lightening of something oppressive, painful, or distressing. For a tap, “relief” is the reducing of surface contact between the tap/tap feature and the part being tapped. Surface contact generates unwanted heat causing the
First things first, what is the root of a tap?
The root of a tap is the surface at the bottom of the thread-form that connects adjacent thread flanks and is expressed as width or as a diameter. The term root diameter is also called minor diameter, it’s one of those things, you say rain and I say precipitation, meaning the same thing.
The root of a tap, unless designed as a controlled root tap, normally does nothing, it is a
We realize how confusing the painstaking math is to get preplate part limits and a Tap “H” limit, but don’t worry, all you have to do is contact us with your thread information, and we will do the work. Call us at 800-USA-TAPS.
If you want to know how it's done, we’ve included the formulas for the engineer in all of us.
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
What tap should be used for deep holes with extra thread length? Why do some applications cause a “No Quote" or “No-Guarantee on Performance” response?
From the perspective of a tap manufacturer, the general rule is that any thread length more than 1-1/2 times diameter is considered “excessive”. It’s a good rule in terms of tap performance. Acceptable strength of thread as determined by length of fastener engagement might best be illustrated by the thickness of an Industry-Standard nut as assigned to its mating bolt. That functionality between nut and bolt seems to have had
If you deal with exotic alloys like Inconel, titanium, Hastelloy, etc., this blog post is written especially for you.
Exotic alloys are alloys designed for high temperature applications (think aerospace), perform in corrosive environments (think underground), or have the highest strength to weight ratios (think earth moving applications). The machinability of these materials is NOT the first consideration. As much as it would be nice to have an aluminum firewall in a helicopter from the machinist’s viewpoint, as the pilot or passenger you want flame retardant and strong.
Some exotic materials can
When discussing Screw Threads, it may be helpful to understand a little of the history behind them.
Let’s start with helical forms. Records dating to around 250 BC establish that it was Greek mathematician Archimedes who explained the mechanical principle of the screw as a form of wedge. He went on to formulate the mathematical characteristics of a helix. This was a precursor to the invention of the “water screw”, which provided a means to move water for irrigation, and as a method for ships to evacuate bilge water. It is apparent that other great
Most cutting taps are available in three chamfers. Taper, plug and bottom are how they are referred to in most of the current literature. Why do we choose one over the other and what are the advantages?
Unlike a drill or center cutting end mill, taps introduce the cutting edges by means of a chamfer. Drills are cutting on the tip (axial), center cutting end mills plunge (axial) then may traverse to cut radially on the workpiece. Most end mills are cutting on the radius, but they are to leave a “straight” or “smooth” finish.Read More