Articles & Columns

This article makes the case that a core drill is the best tool for opening existing holes. Being designed for the operation, the two-flute indexable drill can produce more accurate holes with less tool wear and breakage than alternatives such as boring bars, drills or endmills. The article describes the design of a typical core drill and explains how it is used.

Superabrasive bore finishing can achieve the same results as conventional honing quicker and at a lower cost. This article describes the types of superabrasive tools available and their uses. The article also explains how to set up and break in the tools.

Solid-carbide drills made with advanced submicrograin carbide are capable of producing holes that meet tight specifications without secondary operations. This article explains how these tools produce reamer-like finishes while offering extended tool life and shortened cycle times. An accompanying article discusses coatings for solid-carbide drills.

Modular fixturing offers a flexible and reusable alternative to dedicated fixtures. This article discusses the benefits of modular fixturing and the types of jobs for which a modular system makes economic sense. A description of typical modular fixturing components and how they are used is also provided.

When shops crank up the speed, they have to be prepared for the consequences, even if they’re milling "easy-to-machine" aluminum.

Researchers tried bathing inserts in liquid nitrogen to keep them cool while cutting hard-to-machine materials. This article reports the results of this experiment. It shows how the use of cryogenic coolant can keep temperatures down and prolong tool life while machining titanium aluminum vanadium and reaction-bonded silicon nitride.

Improvements in cermet and ceramic inserts have made them a good choice for high-speed milling. This article describes how the compositions and designs of these newer inserts make them tough enough to withstand the punishment of a milling operation while maintaining the hardness that makes them wear-resistant.

The economic benefits of high-speed machining can be lost if the wrong tools are used. This article describes the types of solid-carbide drills and endmills that can ensure long-running performance. It also covers the proper handling and setup of these tools.

Researchers at Ohio State University produced contoured cuts with different ball mills to determine the best tool material and coating for the job. This article reports their findings and offers recommendations for extended tool life when milling molds and dies.

The advent of CNCs made new threadmaking technologies practical. Among these technologies are rigid tapping and thread milling. This article describes the uses, techniques and benefits of these two threadmaking methods.

There are a variety of presetters on the market. All reduce machine downtime by allowing shops to set up tools offline. This article discusses the different presetter types and the impact that these differences will have on the instrument's price and functionality.

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.

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.

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.

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.

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.

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.

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.

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.

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.