Feature Article

Articles • August 1, 1996 • John Edmond

The Good, the Bad and the Retapped

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.

Articles • August 1, 1996 • Martin Eastman

Quality Through the Tiers

Manufacturing customers have begun demanding that their suppliers institute quality-control processes. At the same time, they are expecting their suppliers to adopt more efficient processes so that suppliers can reduce their prices while maintaining profitability. This article discusses these pressures and how even subtier suppliers are being affected by them.

Articles • June 1, 1996 • Norman Rohr

Powder Particulars

This article describes the shapes and sizes of diamond particles produced through standard manufacturing processes. The uses for these different types of particles are also explained, with an emphasis on particles used in superfinishing powders and slurries.

Articles • June 1, 1996 • Thomas Service

Superabrasive Safety

Standards governing grinding-wheel safety testing do not cover all superabrasive wheels. This article suggests that these standards should include them. The author explains why as he describes a typical superabrasive wheel and the dynamics of superabrasive wheel failure.

Articles • June 1, 1996 • Leonard Pukaite

The Hard Truth

The fundamentals of wheel dressing and truing are reviewed in this article, which covers the proper maintenance of a wide variety of wheel bonds and abrasive types. The article also discusses different truing techniques and their appropriateness for different uses.

Articles • June 1, 1996 • Trevor Howes

Creep-Feed Exam

Researchers at the Center for Grinding Research performed a series of creep-feed grinding tests to determine the causes of the heat damage and striations they observed. The tests involved grinding slots and vertical faces. This report discusses the dynamics behind these problems and suggests ways to avoid them.

Articles • April 1, 1996 • Mike Castner

Modular Moneymakers

Modular toolholding systems save shops money in several ways, according to this article. By making it possible to use the same tools on several machines, for example, a modular toolholding system can allow a shop to reduce its tool inventory. This article explains many other savings in addition to tool inventory reduction.

Articles • April 1, 1996 • Christopher Wilkens

EDM Wire Covers All the Angles

With wire EDM, the properties of the wire will have a large impact on the performance of the operation as well as the ease of rethreading. This article discusses the properties that ensure a good spark and reliable performance even when cutting at an angle. Real-world examples are given of users who have improved their operations by changing the type of wire they were using.

Articles • April 1, 1996 • K.P. Rajurkar

A Spark of Intelligence

EDM cutting conditions change throughout the cutting process as the part thickness and the level of dielectric contamination fluctuates. This article describes an experimental setup that can monitor these fluctuations and adjust the EDM's settings to maintain an optimal spark.

Articles • April 1, 1996 • Lawrence Rhoades

Understanding EDMed Surfaces

EDMing removes material at such high temperatures that the process produces metallurgical changes in the material surrounding the cut. This article discusses the various surface effects and how they can be detected and measured. It also reviews the different methods for correcting or removing the surface flaws and roughness caused by EDMing.

Articles • March 1, 1996 • Ann Marie Rooke

Saw Change

Blades for contour bandsawing vary in their materials, their tooth set and selection, their width and the way they are welded. This article discusses how each of these variables contributes to the blades' ability to cut intricate shapes without seizing or wearing prematurely. Blade lubrication is also covered.

Articles • March 1, 1996 • Louis Caldarera Jr.

Stress Management

High-performance aluminum-alloy workpieces are prone to residual stresses that can lead to part distortion. This article reviews the milling tools and practices that affect these stresses. Some tools and practices alleviate the stress, while others allow the machinist to mill the part without adding more stress.