These Holtests are versatile, self-centering three-point internal micrometers for the accurate and efficient direct-measurement of internal diameters.
Three anvils, evenly spaced at 120° apart, contact the internal wall surfaces and find true alignment with the axis of the bore for accurate ID measurement.
TiN-coated measuring contact points (over 6mm / .275” range models) provide excellent durability and impact resistance and allow the instrument to measure to the bottom of a blind hole (up to 100mm / 4”models).
Highly durable because of carbide-tipped contact points(anvils up to 12mm / .5”models).
Measure deep holes using an extension rod (optional) which is available on models over 6mm (.275") measuring range.
With Ratchet Stop for constant force.
Setting rings for zero point adjustment are optional. • Supplied in fitted plastic case up to 100mm / 4”. Over 100mm / 4” supplied in wooden case.