George Schuetz Director of Precision Gages

2 Jul 2003

An Inside Look At Special Diameters

Sometimes we are faced with making critical inside diameter checks on parts that do not present themselves in a straightforward fashion. Usually these checks are on the inside of some type of bearing, and they can be almost any size.

1 Jun 2003

Micrometer Accuracy: Drunken Threads And Slip-Sticks

Whether it’s a screw thread or digital micrometer, the instrument’s level of precision depends on two factors: the inherent accuracy of the reference (the screw thread or the digital scale) and process errors. With a screw micrometer, accuracy relies on the lead of the screw built into the micrometer barrel.

1 May 2003

Advances In Air Gaging

Over the years, the tooling for air gaging has remained basically the same: steel tubes or rings with precision orifices that set up a pressure/distance curve when in use. As the orifice is restricted, flow is reduced and pressure builds up in the system.

6 Apr 2003

Reverse Polarity: Countering Your Clockwise Indicator

In the last issue, we looked at the advantages of balanced and continuous dial indicators. There are also measurements that require dial indicators with a counterclockwise dial.

2 Mar 2003

All Over The Dial

There are endless variations in the dials used on mechanical dial indicators. In most cases, though, they can be broken down into two distinct styles: balanced and continuous.

5 Feb 2003

Gaging Diameter Variation In Machined Holes

As tolerances for machined holes keep getting tighter, we are learning that no hole possesses a geometrically perfect, symmetrically round shape. No hole is likely to take on a perfect oval (two-lobed) form, either.

Holemaking 3 Jan 2003

Another Way To Square—Or Is It Perpendicular?—It Up

There are a number of tools available for shop personnel to evaluate the right angle relationship between two surfaces. The basic machinist square has a number of variations, the most common being the hardened steel square used to check right angles and set up milling and drilling machines.

Inspection and Measurement 1 Dec 2002

Sliced Bread—And The Limits Of Air Gaging

"Air gaging is the greatest thing since sliced bread," a friend once said. And he was right—air gaging is good.

Inspection and Measurement 1 Nov 2002

Surface Texture From Ra to Rz

The irregularity of a machined surface is the result of the machining process, including the choice of tool; feed and speed of the tool; machine geometry; and environmental conditions. This irregularity consists of high and low spots machined into a surface by the tool bit or a grinding wheel.

Measurement 2 Oct 2002

DFGT - Double Flank Gear Testing

Functional gear testing, also known as total radial composite deviation, is a method of looking at the total effect of gear errors. This test method simulates the conditions under which a set of gears is likely to operate as a result of the gears meshing together.

Measurement 5 Sep 2002

The Three Ds Of Straightness Plugs

We have touched on different applications of air gaging: size, match gaging and form applications such as taper. In this column, we'll discuss air straightness plugs.

Measurement 1 Jul 2002

Stacking Up For Big IDs

For those medium and large parts with inside diameters greater than 4 inches, an inside micrometer is often used as the inspection tool of choice. This is especially true if the volume of parts is low and there is a large range of diameters to account for.