Originally Posted By Joe_Sakic:
Which india stone works best for a trigger job? There's ultra fine, fine, medium and coarse? There's a good detailed section in the M14 Complete Assembly Guide on performing a trigger job - however, I can't locate which grade of stone to use...or a combination of 2 or more?
Thanks in advance!
Just a hunch...start with coarse or medium, and finish with fine.
Have you done anything like this before?
Originally Posted By PR361:
Fine or ultra fine.
Your goal is to NOT remove metal or change any of the geometry, just polish out machine marks and slick up the surfaces.
Machine marks are grooves in the metal.
It's not possible to remove machine marks without changing the geometry.
There's always one.
Without making PERCEPTIPLE changes in the geometry.
Obviously if you polish you are making minute changes to the surface of the metal, but the surfaces can be cleaned up without making perceptible changes in the engagement geometry of the hammer and sear.
Using a course or medium stone will grind quickly, and it is easy to muck op the engagement angles.
Probably not a great idea to start the learning process on your prized M1A, but Buying a used trigger group to play with and learn on might not be a bad idea.
I'm pretty sure you won't be able to measure the difference between a polished and unpolished sear angle with a protracter.
I've done lots of trigger jobs on lots of guns, but I have never bothered with my M14S because, well, it's a battle rifle, not a precision rifle.
Each to his own I was just trying to answer the OPs question, perhaps you can give him the information he needs,,,,
Of course you change geometry when doing a trigger job, that's the whole point. You need to understand the difference between a positive sear angle and a negative sear angle. You need to know how much material you can safely remove before you are through the surface hardening. You need to know how to re-harden metal parts if you make major changes. The Garand/M14 trigger group is easy to do a trigger job on IF you know wear to use the stone. There is a lot more to it than just a fine stone across the contact surfaces.
You can send the trigger group to SAI and they well do a NM job for $25. A quality stone well cost that much. You should have a selection of three or four stone and a trigger block before you start this work.
Thanks for the feedback - mission accomplished! I utilized both a medium & fine stone to perform my trigger job. The instructions are extremely easy to understand + pictures illustrating what needs to be done every step of the way. I took my time this afternoon and had it finalized in just over 2 hours worth of work. My initial trigger weight started out at over 6lbs w/very noticeable creep. The final output is right at 4.5lbs w/no creep whatsoever and is extremely crisp...I'm very satisfied with the results.
Glad you have the fortitude to press on and acomplish your goal and achieved the desired results.