After working in technical support for Fowler for six years, many people asked the question: Why is it necessary to have four pistol grips to cover the range of .08-12”(2-300mm) when using the Folwer/Bowers bore gages?
There are four pistol grips needed to cover the Fowler/Bowers XT Extreme range:
54-556-350 Used with XT Extreme heads from .08-.250”(2-6mm)
54-556-375 Used with XT Extreme heads from .250-.750”(6-20mm)
54-556-400 Used with XT Extreme heads from .750-4.0”(20-100mm)
54-556-480 Used with XT Extreme heads from 4-12”(100-300mm)
Answer: Measuring Force
If you look closely at the four different pistol grips, they look almost identical from the outside. The smaller size pistol grips contain a different thread size where the XT heads are attached to the gun. Inside the pistol grips, there are two springs that differ between the four different sizes. The reason for the different strength springs is larger XT heads will require more measuring force to push the anvils out to the maximum end of their range.
If you have any questions about the Fowler/Bowers XT Pistol Grips, please email [email protected].