Articles & Columns

Tapping holes 1 1/2 times the tap diameter or deeper requires greater care than other tap operations. This article discusses the chip evacuation problems that can make deep-hole tapping a challenge and the tap geometries and flute designs that can tap these holes successfully.

Thread rolling produces OD threads by cold profiling the thread form onto the workpiece rather than cutting. According to this article, this yields significant benefits over using single-point tools to cut threads. The article also discusses the different types of thread-rolling units and their uses on modern machine tools.

Roll-forming taps produce internal threads by displacing the metal under pressure rather than cutting it. This article explains how to perform the operation to achieve good quality threads. Formulas and charts help the user calculate the proper size hole and the size of tap to use for a desired thread.

This article reviews the nomenclature that toolmakers use to identify inserts. Both ANSI and ISO codes are described character by character. A chart lists all of the possible choices for each position in the code and what each code letter or number signifies.

A shop supervisor and education manager recount the evolution of a job that didn't proceed exactly as planned. Because the powder-metal part was harder and its as-pressed dimensions were not as accurate as originally expected, adjustments and improvisations were needed to produce the finished parts as quickly and as cheaply as quoted.

This article compares hard turning to grinding for finishing hardened steel parts and discusses which operation would be more appropriate for various situations. The article also looks at the machine tool, insert and cutting parameters required during hard turning.

According to this article, the short-bar barfeeders that are on the market today are not plagued by the drawbacks that have become associated with barfeeding. The units load 5-foot bar stock into a lathe rather than the longer stock loaded by earlier units. This article describes how shops can use short-bar barfeeders to keep a lathe busy with a steady flow of work and still change from one bar diameter and part program to another easily and quickly.

Copper is difficult to EDM because of its high thermal conductivity. This article discusses the electrodes and machine settings to use for this demanding task.

Honing was originally a surface finishing operation that did not remove significant amounts of material. This article discusses brush honing, a process the authors say produces results similar to what honing was originally intended to produce. Proper boring is also discussed, because, according to the authors, a properly bored hole will not require further correction through modern aggressive stone honing techniques.

The efficiency of a die-sinker EDM operation can be enhanced by automating at least part of the work handling or tool handling. This article describes the automation that is available, from the simplest electrode grippers to fully automated toolchanging systems.

This article discusses the trend among insert makers to consolidate chipbreaker designs and carbide grades. The result is the three-chipbreaker/three-grade matrix many insert makers have adopted in some form. The evolution of the chip-forming groove is also traced, and an ANSI proposal for a grade identification system is described.

A clear and intact substrate surface is important to the success of a coating deposited on a carbide insert. This article looks at the surface problems and contamination, introduced by the insert manufacturing process, that the coating company or insert user must correct before the insert is ready to be coated.

It took years to perfect, but manufacturers finally found a way to economically coat carbide inserts with a diamond film. This article describes the coating process and looks at that companies that are offering diamond-coated tools, the companies that are coating tools for other manufacturers and the companies that are supplying coating equipment. Thick-film diamond is also discussed.

Advancements in bandsawing are allowing shops to closely control the cost and precision of the operation. This article looks at such innovations as informational computer programs that provide advice on workpiece positioning and machine settings. Improvements in blade design and the applicability of these new blade geometries is also covered.

Three different problems can cause a laser to make beveled cuts. As these problems interact, they create distinct patterns of bevel angles that require sophisticated mathematical analysis to sort out. This article discusses an experiment using Fourier analysis to determine which combination of problems caused the cyclical variation that was observed in the measurements of a laser's cutting angle.

Guide bushings are used in difficult holemaking applications to ensure that the drill produces round straight holes. This article discusses the types of bushings commonly used and the materials they are made from. Guidelines for sizing bushings for a given operation are also supplied.

When hole depths exceed four times the drill diameter, problems with cooling and chip evacuation can arise. This article discusses these problems and the drill geometries, machining parameters and coolant options that can minimize them. Charts are included giving speeds and feeds for various workpieces and drill diameters.

Ion implantation bombards a tool's surface with accelerated metal ions. According to this article, the process increases tool life and the performance of tool coatings. Two theories explaining why the process works are also discussed.

For drilling standard holes in metal, there are three primary types of drills: twist, spade and indexable insert. This article discusses the pros and cons of each design and the applications for which each might be appropriate. Factors considered include hole depth, tool cost, drill speed, coolant delivery, tool inventory required, machine tool requirements and expected tool life.

In 1995, the Big Three automakers dropped their individual quality programs and requirements for suppliers and adopted a common program based on ISO 9000. This article discusses how the automakers' standard, called QS-9000, was developed and how they plan to implement and enforce it. Some advice for suppliers planning to earn QS-9000 registration is also given.