All of Western Instruments Pit Gauges have a range of just slightly over 12.7mm or 0.500”, with any one of our 3 types of Contact Points. However, during some inspections, this range is simply not enough. To increase the range of our Pit
Gauges, Western offers a Contact Point Extension (N88-X).
These Extensions are machined to extend the depth of the Contact Point by 12.7mm or 0.50”, thus a properly zeroed Pit Gauge will have a range of 12.7mm to 25.4mm or 0.50” to 1.00”. Like any machined part, there are differences from one to another. This is why our literature states that there could be an error to the Contact Point Extensions of +/-
0.05mm or 0.002”. Greater errors may also be introduced by not tightening either a Contact Point, or Contact Point Extension, enough. Further, using two or more Contact Point Extensions will add (or subtract) error. Therefore. it is always
important to re-zero a Pit Gauge that has had a Contact Point, and/or a Contact Point Extension, added or removed.
Western Instruments Pit Gauge Accessories
Lastly operators must be mindful when using Contact Point Extensions and the importance of holding the Gauge “Normal” (or perpendicular) to the work piece. Due to the use of the knife edge, on the majority of our Pit Gauges, zeroing on a surface is rather forgiving in that the end of the Contact Point remains in the Centerline of the Blade.