Mitutoyo 368-917 Holtest 3-Point Internal Micrometer Set 0.5" - 0.8"

The Mitutoyo 368-917 Holtest is a professional-grade three-point internal micrometer set designed for the accurate and efficient direct measurement of internal bore diameters. Covering a total range of 0.5" to 0.8", the set includes two measuring heads with individual ranges of 0.5"–0.65" and 0.65"–0.8", along with a micrometer head unit, extension rod, and a 0.65" diameter setting ring — everything needed for precise bore measurement right out of the case.

Key Features:

• Self-centering 3-point design: Three anvils spaced evenly at 120° apart automatically center the instrument in the bore, ensuring true axial alignment for accurate, repeatable inside diameter measurements
• TiN-coated contact points: Titanium Nitride (TiN) coating on the measuring contact points provides outstanding wear resistance, impact resistance, and long service life
• Carbide-tipped anvils: Hardened carbide tips add exceptional durability for use in demanding shop environments
• Ratchet stop mechanism: Ensures a constant, consistent measuring force on the hardened-steel spindle for repeatable and accurate readings every time
• Blind hole capability: Instrument geometry allows measurements to be taken close to the bottom of blind bores
• Extension rod included: Enables measurement of deep holes without sacrificing accuracy
• Vernier graduation: 0.0002" graduation with ±0.0001" accuracy for high-precision applications
• Fitted plastic case: Set is supplied in a protective fitted plastic carrying and storage case

Specifications:

• MPN: 368-917
• Series: 368
• Total Measuring Range: 0.5" – 0.8"
• Individual Ranges: 0.5"–0.65" / 0.65"–0.8"
• Graduation: 0.0002"
• Accuracy: ±0.0001"
• Setting Ring Included: 0.65" diameter
• Extension Rod: Included
• Case: Fitted plastic case

The Mitutoyo 368-917 Holtest set is the trusted choice for machinists, quality control technicians, and metrology professionals requiring reliable, high-accuracy bore measurement in the 0.5"–0.8" range.