256MRL-25 Disc-Type Micrometer 51238

256, 256M Disc Type Micrometers with Rotating and Non-Rotating Spindle
Disc-Type Micrometer, Ratchet Thimble, 0-25mm Range

The Starrett 256M Disc-Type Micrometer is used to measure the thickness of work sections such as ribs, lands, fins, cutting edges on form tools, and chordal thickness of gear teeth. Because of their large anvil and spindle faces, the 1" and 25mm sizes are also useful for measuring the thickness of sheet materials like paper, cardboard, rubber, and plastics. 0-25mm Range, 0.01 Grad, Ratchet Stop, Lock Nut.

This item is discontinued. Please consider the recommended alternative listed above or contact our special order department at (978) 249-3551 x410 for more information.

3D CAD Files / Exploded Parts Diagram
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  • Advanced sleeve design with staggered lines and distinct figures for precise and easy readability
  • Quick-reading figures - every thousandth numbered on inch tools
  • Balanced frame and thimble design ensure easy handling and better readability
  • Available in the 1" and 25mm sizes with rotating or non-rotating spindle
  • Quick and easy adjustment
  • Starrett satin chrome finish - no glare - resists rust
  • Ring-type knurled lock nut for quick and sure locking
  • The combination ratchet and speeder for uniform pressure and quicker adjustment on all sizes
  • Gracefully designed tapered frame for use in narrow slots and tight places
  • Anvil and spindle discs are 1/2" (12.7mm) diameter tapering to .015" (0.4mm) edge thickness making it possible to enter narrow grooves and recesses
  • Rigid one-piece frame of drop forged steel
  • Extremely hard and stable one-piece spindle
  • Micro-lapped measuring faces
  • This tool is accurate to .00015" or 0.003mm measuring over the whole surface and .0002" or 0.004mm measuring on the edges


  • Made in America: Yes
  • Micrometer Type: Disc-Type Micrometers with rotating spindle
  • Range (mm): 0-25mm
  • Graduations (mm): 0.01mm
  • Anvil/Spindle Material: Steel
  • Anvil Type: Flat Disk
  • Spindle Type: Flat Disk
  • Lock Nut Type: Knurled Ring Type
  • Thimble Type: Ratchet


    2D Dimensional Drawing (PDF)



    121.99 kb



    Catalog 33 - Section 1 - Micrometers
    The L.S. Starrett Company

    In the hands of a skilled operator, the precision micrometer is the most accurate hand-held tool available. When close measurements are necessary, the micrometer is the ideal tool for the job because measurement and reading are on the same axis and the anvil end is supported by a strong frame.

    [69 pages]

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      Member of Kit
      Item #DescriptionPart No.QtyInformation
      20NUT, .375-52PT164141
      30ANVIL, FRAME #25618528-01
      40LOCK NUT, #230PT990601
      50•RING, FRICTION05324-01
      60•RING, BINDER09209-01
      70•ROLL, BINDERPT053251
      80WRENCH #3PT015261
      90SPRING, BARREL10058-01
      110•SPINDLE ANVIL13695-01
      130•CAP ASSEMBLYPT994451
      150••CAP, RATCHET07671-B1
      160•BODY, RATCHET #23019773-01
      170•PIN, RATCHET .066D X .156LPT189761
      180•SPRING, .041X.061X.188X.010X6PT076731
      190•SCREW, #2-64 SLOT X .204 LONGPT197721
      200SHELL, METRIC14947-01
      210SHELL, ADJ. METRIC05134-M1

    California Proposition 65 Warning

      WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer, and birth defects or other reproductive harm. For more information go to: www.P65Warnings.ca.gov