Author Topic: Starrett #120 caliper - realign zero  (Read 2417 times)


Starrett #120 caliper - realign zero
« on: August 22, 2019, 10:57:40 PM »
I picked up a Starrett #120 6" dial caliper in great condition. But the zero point was at the 6 o'clock position.

To realign the arm back to 12 o'clock I removed the 4 screws on the face of the dial housing, and the whole front plate easily lifts off. No loose parts, no springs to fly out. Very easy to do.
I cleaned out any debris from the depth blade, behind the bezel, and around the innards of the caliper. I also cleaned the rack.

By hand, I turned the small gear till the hand pointed in the 12 o'clock position. With the caliper fully closed and locked, I was able to place the front dial plate back onto the caliper.

The small gear is slightly spring loaded. With the caliper flat on my table I started inserting the gear back into the rack with top of the gear in a nose down sort of angle. The bezel plate 12 o'clock pointing down towards my table. Lightly pushing the gear forward into the rack with a slight upward sweeping motion to preload the gear spring allowing the plate to then lay flat as the gear seated into the rack.
I had to do this twice as my first attempt resulted in my inadvertantly moving the needle off zero/12 o'clock. Second attempt got me close enough.

Inserted the 4 screws, and done. Brand new!


Re: Starrett #120 caliper - realign zero
« Reply #1 on: August 23, 2019, 07:45:27 AM »
There you go, you got it pretty close.  I personally would not mess with it anymore than that.

Again, very nice find!!!

Now you have to get the Starrett 12" pair to go with your 6" pair. ;D