Posted: 8/22/2012 6:56:53 AM EDT
| Is there a shop expedient way to determine the spring weight of mainsprings and recoil springs that are already in a gun? Thanks. |
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You used to be able to buy spring testers. I have a spring postage scale (looks a bit like a fishing scale) that I have rigged up to weigh springs. It works pretty well.
Basically I have a steel rod with a nut at one end and a hole drilled in the other. I put the spring on the rod, and then follow that with a metal bar with a hole drilled through it. Hook the scale onto the end of the rod. I chuck the metal bar in a vise, and pull the rod with the scale until the spring is at full compression. (I have a paint mark on the rod at this point.) Read the scale and I'm within a half pound of the full compression force. This tends to only work for recoil springs. You could build something similar for mainsprings but I don't really find it necessary... I can estimate them pretty closely by feel. If you were insistent on building a testing tool for those, it is easy to put together something that will work with a digital bathroom scale. Think a flat metal plate a few inches in size, with a steel rod sticking up from the center. Put the spring over the steel rod, and use a metal bar with a hole in the middle to press the spring into its fully compressed length. |