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Tapping

Rigid Rules

08/01/1996
Author:
Allen Krenick
There are some tapping situations that call for a rigid tapholder and some that call for a length-compensating holder. Often the choice depends on the capabilities of the machine and the CNC driving the tap. This article discusses why a machinist might choose one type of tapholder or the other.
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The Good, the Bad and the Retapped

08/01/1996
Author:
John Edmond
Internal threads can end up undersized because of the work material's properties or because of changes to the hole's dimensions caused by plating or heat-treating processes performed after tapping. This article explains H- and D-limits and how to use them to specify a tap that will produce the right size thread, regardless of any post-tapping operations.
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The Need for Feed Units

02/01/1997
Author:
Tom Lingafelter
There are several types of feed units for drilling and tapping on the market, varying in capability and the type of drive. This article discusses the difference between units and suggests questions users should ask themselves before selecting a unit. Factors to be considered include the volume of production, cost engineering and tool requirements.
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Know What You're Tapping

09/01/1997
Author:
David Miskinis
Traditional tap/drill charts recommend drill diameters for each size of tapped hole. But, according to this article, these recommendations are based on the size holes that were typically produced by less-accurate tools and processes used in the past. This article suggests guidelines for producing holes that will, in turn, produce correctly sized tapped holes.
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Thread Heads

01/01/2000
Author:
Dennis Esford
Three companies that tap millions of holes annually offer advice for improving the tapping of steel and aluminum. Discussed is coolant application, equipment for tapping and determining speeds. There's also a sidebar on thread milling.
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Speed Tapping

08/01/1998
Author:
David Ridenour
Tap and tapholder manufacturers have introduced technology to speed up the inherently slow tapping process. This article reviews a number of innovations, including tension/compression holders for rigid tapping, self-reversing tapping heads and quick-change tapholders.
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Pipe Tapping

10/01/1998
Author:
Wes Emerson
Taper pipe threading is unlike any other threading operation, and it may be one of the most difficult operations a machinist can be asked to perform. This article reviews the various types of taper threads and the tools and techniques needed to produce them.
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TNC 640 Mill-Turn Control With Touch Technology

TNC 640 Mill-Turn Control With Touch Technology
The TNC 640, HEIDENHAIN’s high-performance mill-turn control, is popular with users thanks to its workshop-oriented operational design. Now the TNC 640 is, and will only be, available with groundbreaking touch technology that supplements the TNC 640’s field-proven cycles and functions. It allows the user to operate the control screen with gestures, similar to smartphones or tablets.

Admitting my mistakes

I received an email from a reader letting me know that he disagreed with my recent article on tapping versus thread milling. In it, I stated, “There’s little chance of successfully thread milling metals much above 45 HRC. And if you’re going to try to tap them, be prepared to duck the flying shrapnel when the tap explodes!” We all make mistakes. So when Tom Fares, president of TNT Custom Equipment in Stow, Ohio, called me out on that section of the article, saying that he routinely taps holes in 45 HRC steel alloy and thread mills into “the low 60s,” I listened to what he had to say.