Class X Pin Sets & Libraries

Home/Products/Class X Pin Sets & Libraries

100% Inspected for ACCURACY!
Offers the same “features” as our Class Z pin gages but with .00004” tolerance limit and .00002” roundness limit. These pin gage sets are perfect for critical inspection needs or when you want to maximize your GO/NOGO tolerance limits. They’re also a great way to calibrate measuring equipment, micrometers and calipers.

Class X Sets & Libraries information & pricing


  • All gages and sets are traceable to N.I.S.T.
  • Boxes and pin gages both marked
  • Size and serial number laser etched on each piece (M-OX not etched)
  • Material: 52100 Bearing Steel
  • No sharp edges
  • All members 2” long


  • Checking locations
  • Measuring hole sizes and depth
  • GO & NO/GO gaging
  • Setting micrometers
  • Checking distances between holes


  • Centerless lapped
  • Each gage is inspected and has a 2 microfinish or better
  • Heat treated to a hardness of 60-62 Rockwell C
  • All English gages with .00004” limit

Used as masters to calibrate measuring equipment and check linearity of comparators, micrometers, and calipers. These “Tenth Step” pin gage sets have unlimited applications, such as quality control inspection, prototype work and production layout. Inspectors select from the range of pins to find the size of a hole or slot. These round masters simulate a cylindrical part which, unlike flat blocks, can detect uneven wear on the tips of micrometers and calipers. The thin “line” of contact detects uneven face wear better than flat gage blocks with large contact area.


  • Each set contains 25 pieces of Class X tolerance (.00004”) gage pins. Traceable to NIST.
  • Choice of two tolerances: Plus (+.00004”) or Minus (-.00004”)
  • Sets consist of a center nominal size, and 12 gages larger in .0001” steps and 12 gages smaller in .0001” steps.
  • Each gage is inspected and has a 2 microfinish or better.
  • Heat treated and through hardened to 60-62 Rockwell C
  • All pin gages over .060” or 1. 51mm are laser marked with size direction of tolerance and serial number for traceability.