Measuring drill rod...calipers and micrometers.

[AlanHaisley]

When I was quite young, my dad explained micrometer feel, not as pressure on the barrel or spindle, but as drag on the anvil. The idea was that dragging the part through the anvil opening or moving the anvil over the part allowed for a more consistant feel than trying to repeat a particular torque on the spindle each time.

With a caliper, I try for the least contact I can feel, as far toward the base of the jaws as I can reach. I'm not sure I ever get any kind of repeatability though. As others keep saying, key is practice. Don't just stick with that free .25" gauge pin though. You want your muscle memory to be there for a wide range of hand positions. Especially with the mic, where your hold is quite different on a 1/16" rod vs. a 7/8" rod.

 

[zeeprogrammer]

I got a lot more out of this thread than I bargained for.

Thanks to everyone for their very helpful advice.

:bow:

 

[IronHorse]

Nobody mentioned that the wheel on a set of calipers is like the ratchet on a micrometer, close the jaws with a light pressure on the wheel, and take a reading when the wheel spins with no more jaw movement (wheel slip) I use this method to get consistent readings.


IronHorse

 

[Brian Rupnow]

After numerous mishaps "turning to size" after measuring with a digital caliper (and consequently ending up with UNDERSIZE scrap, I have quit measuring lathe work with my calipers. I now use a micrometer to measure lathework, and find it is much more accurate.