Zero moved caliper

Hexhead

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I had a weird thing happened the other day, my Starrett caliper (American-made) decided to change its zero point. It was on the 12 o'clock position and now it's in the 3 o'clock position .My first thought was that was some debris and between the jaws. I cleaned them so many times I think I was starting to removing metal! They had been right on and working perfectly before this happened. I have a magnet on my toolbox and when I'm not using them I stick it to the magnet. I've been doing it for a long time with no ill effects, just thought I'd run it by you guys and see if it's ever happened to you.
 
My Starrett was at 12 o'clock when I got them off Fleecebay about 10/12 years ago. Several years ago I dropped them from about 4-6" and when I picked them up it was zeroing at 11 o'clock. They're still dead on so I don't guess it really makes any difference.
 
You probably had a small sliver of metal or other debris get in on the rack and the pinion then jumped a number of teeth. Check the rack carefully for damage and make sure that you get rid of any tiny chips that might be in there.

I went through an issue with a caliper that I recently obtained in that it was damaged when I received it. A number of rack teeth were actually damaged and I had to replace the rack and the pinions on the back of the dial.

There are a couple of ways that you can go about correcting the problem if it is important to you to have the needle zero at twelve o'clock, but I would check it with some known measurements first to see if it is still accurate. If it is not, or you simply wish to have the problem corrected, your best bet would most likely be to take it to a local tool company that deals in precision tools and have it corrected and calibrated.

UPDATE: Storing your caliper on a magnet may have slightly magnetized your caliper over time also, and it now attracts little chips and other bits of metal on its own. Not something I would want my caliper to do.
 
I had a weird thing happened the other day, my Starrett caliper (American-made) decided to change its zero point. It was on the 12 o'clock position and now it's in the 3 o'clock position .My first thought was that was some debris and between the jaws. I cleaned them so many times I think I was starting to removing metal! They had been right on and working perfectly before this happened. I have a magnet on my toolbox and when I'm not using them I stick it to the magnet. I've been doing it for a long time with no ill effects, just thought I'd run it by you guys and see if it's ever happened to you.

If you feel you need it at 12 o'clock you can put it back there by slipping a thin piece of shim stock in under the rack and move it slightly. There used to be a little shim tool to do
this, it looks like a T shaped piece of shim stock with the long side of the shim about 1/8
wide and about an inch long.
jimsehr
 
Thanks guys, Now you mentioned it I do remember it catching awhile back, I'll bet that's when it happened. I don't have to have it at 12. I want it there because that's where I've gotten used to it being. I'm a same's kind of guy I like things the way they are. :). I'm going to try getting it back as suggested, I think I'm going to abandon the magnet thing. I usually don't get my caliper near swarf but it just may have picked something up....Thanks again
 
the people above said what happened a small chip got in the rack and the spring loaded pinion jumped a tooth I have used the shim to some degree . but I have found that the newer calipers the shim didn't work. so I got a needle puller at amazon. and now I just pull the needle and reposition it this is just for normality. not accuracy it doesn't matter where the needle is just turn the ring It just looks better then the calipers are closed the needle is at 12:eek:o bill
 
If the pinion jumps a tooth you need to make sure that the debris is removed. The caliper will sometimes jump a tooth going out, giving an erroneous reading but when you bring it back to zero it will jump back to its original setting, giving the impression that nothing is wrong.
 
As RJ said, Always make sure the debris is cleared. The needle can jump in both directions if that debris in not removed from the rack. Open the calipers all the way up and use a magnifying glass or headset to check the rack. Sometimes even the smallest piece in the rack can make the needle jump.
 
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