The English micrometer above is similar to those available in the shop. Navigation Home Upcoming Events Random page. On the sleeve, the measurements of the micrometer are labeled in one-tenth of an inch increments with each line on the sleeve indicating 25-thousandths of an inch.
Use the horizontal line on the sleeve to reference the thimble measurement. The anatomy of an outside micrometer is show below:. Step 2 - Position Place the measuring rod into the hole or onto the step being measured, as close to the edge but not touching as possible.
It has a range of 0 to 6 inches, depending on the length of the extension rod used. When this occurs the user is to retract the rod until the base is returned to its flat position and the user will twist the cap until it clicks. It is beneficial to the user to write these numbers down until one is familiar with reading a micrometer.
Common practice is to move or slide the depth micrometer along the flat surface to ensure there is drag along the bottom of the hole or slot. The same millimeter thread, and other components, can be used for this purpose.
If you have a 12" micrometer, add 11" to your reading. Carefully turn the ratchet as you approach the surface to be measured and continue turning until the spindle stops rotating.
Jump to: How to Operate: As the shaft threads into the shell, the shell expends to meet the diameter of the given hole or slot. A micrometer is a measurement device incorporating a calibrated screw used widely for precise measurement of small distances in mechanical engineering and machining as well as most mechanical trades. Throughout the late 1800's and 1900's micrometers led to increased standards of quality across all manufacturing fields and have played a vital role in complex mechanical systems for the past 100 years.
In this case,. This procedure is the same for all external micrometers. The last line shown on the thimble below the horizontal sleeve line is the number in ten-thousandths that will be added to the dimension.
Clean the mounting surfaces of the measurement rod and the rod-receiving shaft.
Hole gauges come in a variety of sizes and there are plenty in the shop to fit your application. See picture:. Read the measured value, and add this to the length of the extension rod used.