[Farmall] tools

cvill cvill at frontiernet.net
Thu Nov 26 06:16:42 PST 2009


farmallgray at aol.com wrote:
>
>
> I also have a question on using a dial caliper for you machinists; how much pressure should you use when closing a caliper to take a measurement? I have noticed that if you put more pressure on the thumb wheel you can spring the mechanism to get a different reading.
> On a micrometer you have the ratchet knob that limits how tight you can make it, but a dial caliper doesn't have this.
>
>
> Todd Markle 
>
> Spring Mills, Pa.
>
>
>   
Almost no pressure, Todd.  That is why it is called contact 
measurement.  You simply want to make contact.  One must develop a 
"feel" for the instrument.  It is very important to make sure the piece 
being measured is square or flat to the instrument.  With round work in 
a micrometer, I usually give the work piece a partial turn.  By doing 
this you can feel if there is dirt on the surface and also if the work 
piece is out of skew with the mic. With the vernier, it is usually a 
little left/right canter to feel if the the instrument is correctly 
positioned.  Remember, a diagonal line is always longer than a straight 
line, making an incorrect reading.  If you use a micrometer frequently 
enough to develop a "feel" for it, you will not want to use the ratchet 
any longer.  You will get a lot more feed back from your touch on the 
barrel.

I hope this is the info you were looking for.
Charlie V. in WNY
48 years and 3 months in the metal turning industry before retirement.  
I guess that could be called a life sentence!!



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