To make a long story short, I stoned the trigger of my USFA because it was damaged. Reassembling the gun and checking timing, it was off, DUH! The hammer full cock notch would lock in just before the bolt dropped into the alignment notch, but only if you put drag on the cylinder while slowly cocking the gun. Normal cocking was not an issue. Well, today I set out to fix the problem. Look at the trigger to hammer fit. If you shorten the trigger, it will drop into the notches earlier than before it was shortened. Okay, this means that the arm needs to be longer. Your choices are to buy a new arm, or draw it. I drew it. Now I own an antique car and there are parts just not available so I learned how to draw. Step by step, and this is not for the faint of heart, or if you do not understand the timing of a SAA. Also I was done in less han 30 minutes with everything put back together.
1. Find the time when you are alone. Wife went to Chicago..
2. Dissasemble and clean the parts throughly
3. Remove the arm spring from the arm. I will not tell you how I accomplished this as I need to find out the correct way, not my way. I am open to suggestions.
4. Get out your propane torch and heat the arm until it is cherry red.
5. Draw it by hitting it with a hammer. It lengthens the metal. Be careful. To much gusto and a new part will be needed.
6. Since the part was drawn, most likely it will now have a curve in it. Reheat and take that out
7. Assemble and test to see if it is long enough. You do not need the arm spring to do this if there is enough movement in the arm to hammer pin. (took me four times to get it long enough and this is mere thousanths of an inch is all that was needed.)
8. Oil it good, install the hand spring, and now the hammer goes to full cock at the same time the bolt drops into the final notch.
Since I had learned to draw, rivet and a few other really odd things to repair my antique car, the drawing was not an issue for me. However if you have never drawn parts, You might want to try it out on junk parts first. The bigger the part, the more heat and I have used a cutting torch tip to get enough heat on my car parts. Also, I used a propane torch, but my plumber always uses MAPP gas. I think that MAPP burns slightly hotter. At any rate I am happy with the results. Next I need some spring steel to make a couple of arm springs. Wonder where around here I can find that stuff. Buying the spring is no big deal, But I am always making springs for one reason or another, and it takes about as much time as ordering the part.