Machining

This is the first in a series of Articles on coolants. It provides a general review of the types of fluids available, their cooling and lubricating abilities and their ease of disposal. Criteria are offered for selecting the appropriate fluid for an operation.

The EPA's ban on ozone-depleting chemicals had an impact on the formulation of metalworking fluids containing 1,1,1 trichloroethane. This article looks at the reasons for the ban and the industry's efforts to find replacement substances for the banned chemicals.

When machinists plan a boring operation, they must rely on general turning data. Typically, this data is developed from OD turning operations, not boring operations. This article provides cutting data and recommendations specifically for boring that take into account such unique problems as boring bar deflection and chips trapped inside the bore.

Changes in milling practices have placed new demands on the cutting tool. This article discusses the features toolmakers have added to their milling insert geometries to control chips and cutting forces. The article also reviews the milling process and the forces that act on the insert.

Thread rolling produces external threads by forming the profile instead of cutting it. This guide covers where CNC thread rolling fits, why it can outperform cutting, and what shops should watch in setup.

The choice of tapping driver, the component between the spindle and the tap, can affect the quality and accuracy of the threads as well as the rate of wear on the tap and the machine tool. This article discusses how features such as length compensation and self-reversing protect against damage caused by machine and tool errors.

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.

Deep-hole tapping raises chip evacuation, lubrication, and torque risk. This guide covers practical depth limits, tap selection, and process controls for deeper threaded holes.

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.

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.

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.

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.