Common Terminology

ID – Inside Diameter
OD – Outside Diameter
Wall Variation – Changes in the thickness of the wall
Mismatch – Where the drilled ID meets in the middle when a part is drilled from both ends
Tool Mark – Circular groove in the ID
RMS – ID or OD surface finish (the smaller the number, the smoother the surface finish)
Drift – “Pass-Fail” test where a bar of given dimensions has to pass through the ID
Concentricity – ID Centerline compared with OD axis centerline
One End Only – Drilled from only one end to avoid mismatch
Step Bore – Changes hole size along the part
Blind Hole – Hole does not go all the way through the part
Core – Solid piece out of the center of a trepanned hole

Contact Information
For more information,
call us at:
1-800-375-BORE (2673)
(Within the USA)
1-281-977-7100
(Outside the USA)
Or fax us at:
1-281-449-8702