Archive for November, 2009

This week’s tip: Setting up a mandrel mic

Posted in Uncategorized on November 10, 2009 by Peter

The advantage of a mandrel micrometer is, one tool can do the work of several, saving you money and space.  A typical mandrel mic covers a range of six inches, versus only one inch for a regular mic.

Here’s the issue: Because mandrel mics have multiple anvils, you have to set them up correctly,  which means consistently, which means a procedure.  Check out these two pictures, paying attention to the tube face in the first and the back of the locking ring in the second.

ToolTipsMandrel (2)ToolTipsMandrel

Both of these surfaces have to be extra-clean so that they sit perfectly flat against each other.  If they don’t, the anvil will be at a slight angle and you won’t get reliably accurate readings.

Now look at the next picture.  ToolTipsMandrel (1)You’ll see an arrow etched into the  anvil tube, and numbers on the anvil itself.  With this particular mic, you would always line up the numbers on each anvil with the arrow (each manufacturer accomplishes this a little differently).  That’s what MPTS does when we calibrate mandrel mics.  You’ll get good measurements when you do the same.

Finally, mandrel mics usually come with a set of standards spanning the range of the mic.  After you’ve attached the anvil you’ll be using, always check the mic against the standard.  If it measures right on, you’re good to go.

Next time:  Other mandrel mic issues.