my caliper......junk or normal????

[Shoot'n Hogs]

I have a mechanical stainless steel caliper. This will be difficult to explain but here goes. When you open it up to measure a casing, the tips of the jaws (flat part, not the edged section) measure different from the part closest to the body. The same goes for the middle of the jaw. The caliper is new from cabelas. When the jaws are closed, they appear to be flush. Is this normal? Where should I take the measurement from? Any help would be nice. Thanks!

 

[Dave King]

Measure a small piece of round wire (same orientation and location on the wire) at various locations along the caliper jaws.

When you close the empty caliper jaws does the dial always read -0-??

 

[Shoot'n Hogs]

I set the caliper dial to zero.
Then I moved it back and forth(over and over again)and it still reads zero. But I still have the same problem mentioned in the above post.

 

[JustC]

even a slight pressure will "flex" the thinner part of the caliper blades and give different readings. Always measure anything you are going to use pressure on,..with the thick part of the blades. I discovered this a year or so ago.

 

[D.P.]

Use Daves method and even better if you have a pin gauge, or new drill bit use the shaft. If you measure a tapered case or even the neck the flat part of the jaws will pick up the high spots.

 

[NorthernSniper]

My calipers do exactly the same thing, my solution is to measure at the point where the calipers broaden out. Basicaly I just use the same point on the caliper jaws to measure what ever I happen to be measuring this gives me repeatable measurements. Generaly my calipers can measure better than I can see anyway.

 

[4ked Horn]

I used to be a machinist and I will first say that many measuring devices take a small bit of practice to use consistently. So practice.

You dont need any extra pressure while closing the jaws than it takes to contact the surfaces to be measured. Dont squeeze.

If you want to read increments smaller than .001" stop using a caliper and use a micrometer of an appropriate size and that has a .0001" vernier scale. If you are splitting the gap with your dial caliper needle, stop it. You have the wrong tool.

If, after a short time of getting used to your calipers you measure an object of known dimension and get different results (+/- .001")from the tip of the jaws than the throat of the jaws then either return them or give them to someone that dosent care and get some good calipers. If your eyesight is good I would recomend vernier calipers as there are no fine gears to worry about breaking should debris gather on the rack.