Starrett Vernier Caliper Rule 48 inch
This is a special purpose 48" long vernier caliper, designed and built for the tire mold industry of the past. It is made up of a 48" heavy duty steel rule marked "THE L.S.S. CO. ATHOL MASS. U.S.A." on one side, special fitted caliper jaws, and a strengthing beam the runs the full length of the rule. As you can see, there are two very sharpe point tips, one in each jaw, (the purpose was to inspect distances between very small, (fine detail in the tire mold or similar application) design process or layout. To set the pins to the rule there is a scribe line on the moving jaw in the area next to the rule scale, or you can use the inside jaw surface of the caliper jaw to read the scale when you want to use the inside jaws for measurement. This caliper rule is over 50 years old, yet is in good+ useable condition, measures good, and according to the scale lines as mentioned above. We do note a darkened steel finish, (not bright steel like when it was new) but it is not rusty or dirty, just an aged finish. We note some rubs and scratches on about 10% of the overall surface of the rule, and one area between the 43 and 44 inch locating of the rule where a small part of the increment lines are rubbed off (not on the side used to read the caliper), otherwise all the graduation lines can be clear seen. The rule is a special rule for this type of application as it has a blank extension at the end to allow space to attach the solid caliper jaw in line with the 0 graduation mark. The moving caliper fine adjustment feature is the micrometer barrel type with .025" per full turn, .001" graduations. The lock screw on the moving head is slightly bent on the thumbscrew head with the knurled surface area. Both screw work just fine to lock the caliper or fine adjustment in place. The non-moving jaw is pinned in place, as it the stiffening beam so there is no screws to lock on unlock for these features. It is possible that this was a special order tool made by Starrett, or it may have been made by the tire mold shop. I also note that the pin points are the threaded type, and there is threads in the caliper jaws, but the threads on these pins that are included are just a little bit loose, or undersize, so they are removeable, replaceable, but generally need to have industrial glue added to the thread to keep them fitting tight on the caliper jaws area. A very unique tool! I have never seen another quite like this one! Works good!