Thanks Mike. I'll look that up.
Bonny that's a good point but I wouldn't use a high end set of gauges to prototype something like this. Will this contraption give acceptable results? We'll find out when it's finished.
This type of gauge operates on a very simple principle: Spring tension holds the button (anvil) against the part being measured. Inside the gauge handle is a steel rod that fits inside the lock nut and locking portion of the anvil. Turning the lock nut at the top of the handle locks the anvil in position. Measuring the width of the anvil with a micrometer or caliper reveals the inside diameter of the work piece. We have the parts ready so let's put this thing together.
The handles from the A & B gauges is soft soldered into the tubing. Both fit perfectly inside the tube so it took very little solder to lock them in place.
Working from the anvil end the wire is inserted and trimmed to length.
With the anvil installed the wire is again checked for proper length at the lock nut end.
When the wire length is set the lock nut is installed. Here's the final product:
At 36" total length we can reach the muzzle of even the longest barrel from the breech which makes things much simpler when checking the inside diameter of a choke bored barrel.
We'll put it to use next and do some testing for accuracy.
Hank
