Machining

Articles • April 1, 1997 • Jimmy Sherman

Grading Graphite

This report details the results of a test of graphite electrodes. The test compared the performance and machinability of three graphite grades, ranging from an inexpensive coarse grade to a relatively costly ultrafine grade.

Articles • March 1, 1997 • Mike Castner

Turning Stainless Made Painless

Stainless steel is one of the more difficult materials to cut. This article discusses the problems that can occur when turning various types of stainless steels, the reasons for these problems and ways to avoid them. Advice is given on diagnosing problems based on tool-wear patterns. The article also suggests ways to correct problems once they are discovered.

Articles • March 1, 1997 • Charlie Carland

2 Spindles Are Better Than 1

Dual-spindle turning centers allow shops to combine several processes into one setup. This article describes a typical dual-spindle turning center's configuration and capabilities. A common scenario is given showing how such a machine might be used to reduce cycle times.

Articles • February 1, 1997 • Tom Lingafelter

The Need for Feed Units

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.

Articles • February 1, 1997 • Brent Lindsey

The Performance Edge

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.

Articles • October 1, 1996 • Tom Howes

The High Speed Aluminum Challenge

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

Articles • October 1, 1996 • Timothy White

Hole in One

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.

Articles • October 1, 1996 • Robert Marvin

A Super Finish

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.

Articles • August 1, 1996 • Peter Zierhut

New Twists on Threading

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.

Articles • August 1, 1996 • Allen Krenick

Rigid Rules

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.

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 • 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.