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Old February 17, 2002, 06:51 PM   #2
Blackhawk
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Join Date: November 4, 2001
Posts: 5,040
Part two:

1. Trigger length of travel. To adjust it, you will need an accurate measuring device, such as machinist's calipers, accurate to 0.001", a fine taper (triangular section) file, magnification, such as a jeweler's loupe, and a lot of patience.

The trigger "length" of travel is a function of how far the trigger bar has to move from the time it engages the hammer until it disengages the hammer due to the hammer's rotation. This adjustment involves modifying the hammer, and it should be done very conservatively. Remove too much metal, and your hammer will be junk. It's far better to adjust it a little at a time, measure, adjust, measure, etc., than to try to get what you want in one calculated step.

Remove the frame.

Remove the slide stop and slide stop spring since they won't be needed until you're ready for final reassembly.

Attach a rubber band to one end of a regular paper clip. Place the paper clip against the trigger bar and pull the rubber band around the frame and over the other end of the paper clip near the hammer. Place another paper clip/rubber band combo forward of the first one. These retain the trigger bar in its operating position and allow it to engage the hammer normally. The paper clips are very loose against the frame -- they just act as the grip vis-a-vis the trigger bar.

Use another paper clip and rubber band to simulate the hammer spring in action. Hook the paper clip into the eye of the hammer spring, attach the rubber band, and attach the other end of the rubber band to something substantial.

What you're going to be doing with the rubber bands and paper clips is make a "fixture" so you can study and measure the interaction among the trigger, the trigger bar, and the hammer. You'll be able to hold the frame with one hand and repeatedly pull the trigger with the other.

Carefully use a bit of masking tape on the inside of trigger guard to mark the center of the tip of the trigger above the guard, but be sure to take up the reset over travel (the right point is where the trigger bar won't move forward without rotating the hammer). Raise the frame against its simulated hammer spring (formerly called a rubber band), and slowly pull the trigger, noting the exact point where the hammer releases. Mark that point on the trigger guard with another piece of masking tape. That's the original trigger length of travel, which can be shortened but not lengthened.

Measure it with the calipers, and write the measurement down!

Remove the trigger bar and hammer from the frame. Hold the two parts in their relative operating positions, and observe exactly how they work together. You will see that if you file the hammer and remove metal from where the trigger bar engages it, the release will be earlier effectively shortening the trigger length of travel. There's no great trick to filing the hammer beyond common sense. Make sure you file the edge so it remains square -- in this case exactly parallel to the hammer axis.

Use the caliper or a micrometer to measure the distance from the edge to be filed to an opposite surface on the hammer. Write it down!

Carefully file no more than 0.015" from the trigger bar engagement edge. Use magnification to make sure the edge is square! Carefully "break" the sharp edge after filing by filing a chamfer on it. Sharp edges will wear very quickly throwing everything out of adjustment. You should be able to see the chamfer with magnification.

Reassemble the frame and paper clip/rubber band fixtures. Measure everything again, including the new trigger length. Notice how filing a little off the hammer makes a big difference in the trigger length.

Repeat the filing procedure until you get the trigger length to be what you want. I recommend 0.55" because that will allow the trigger stroke to begin exactly in the center of the grip and end just before contacting the grip.

After you get the length you want, use the file to shape the profile of the hammer below the edge you filed. This isn't necessary, but it's good practice. Remember that all edges should be smooth and square. Be slow. Be careful, and take advantage of the square edges and perpendicular surfaces on your caliper to judge squareness under magnification.

Last edited by Blackhawk; February 18, 2002 at 04:21 PM.
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