If you need to reach into small holes or grooves you can use any one of the test indicator points which have either M1.4 or M1.7 threads, a 2 mm diameter shaft, a length of up to 5" and a small diameter carbide or ruby ball at the end. This is accomplished with an Adapt-A-Tip adapter. The adapter is about .33" long and it screws into any dial or digital indicator spindle which has a 4-48 thread. Then you screw the test indicator contact point into the adapter. It's an excellent solution for fitting into tight spots.
Adapt-A-Tip shown. The test indicator point is not included and is shown as an example of this adapter's use.
NUTS & BOLTS
Easy reading for anyone curious about the origins of mechanical engineering.
HOW WAS THAT BUILT?
From the Brooklyn Bridge to the Sapporo Dome in Japan.
"Perfect for browsing by young readers with an interest in engineering or architecture." - Wall Street Journal
STARRETT
An American Manufacturing Tradition