Posted 03 September 2005 - 08:58 PM
I was just curious as to how frequently Thompson springs should be replaced.
Its possible with the WH receivers, that failure to replace springs more frequently could be part of the problem with cracked receivers. Granted the metal is a part of the equation as well.
In a few previous threads I've noticed its time to replace when they stop working.
Just a thought.
Posted 05 September 2005 - 07:07 AM
Because of field constraints, the easiest way to check the spring is to measure it’s overall length. GI manuals say 10.25” is minimum. This assumes that the spring has not been cut (it should have 69-72 coils). This spec is the same for ’28 & M1. Some manuals show a slightly different length spec.
A kinked spring should never be used. A little wave is ok, but the straighter the better.
If the fit of the pilot and receiver are correct, there should be little evidence of pilot canting. If you place the pilot into the receiver without the spring, the free end should move in a circle of (I’m estimating) about 1/8” max. If it’s loose, you risk spring kinking and the wear problems Phil noted above. Most kinked springs are caused by sloppy assembly/ disassembly techniques.
Posted 05 September 2005 - 08:05 AM
The same should work for other auto loaders and MG's as well I would think.
The 1911 crowd most likely arrived at the same answer the same way. Then through observation narrowed it down to an approximate amount of rounds fired and replacement.
Posted 05 September 2005 - 11:19 AM