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Old June 23, 2002, 05:18 PM   #16
Blackhawk
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Join Date: November 4, 2001
Posts: 5,040
Part four (Revised):

Part four (Revised):

3. Trigger reset overtravel adjustment. After the trigger is pulled, the trigger bar tang has to re-engage the hammer for the next shot. The objective of this adjustment is to have the trigger go forward just a little farther than necessary to reset the trigger bar.

The adjustment is made by using J-B Weld to build up the bell crank recess in the frame where the trigger bell crank rotates, then trimming it to limit the bell crank's rotation thus limiting the trigger's forward travel.

Disassemble the pistol, and remove the frame from the grip. Use Q-Tips and alcohol to thoroughly remove all oil or grease from the aft part of the trigger bell crank recess. The bell crank itself is liable to have oil under it, so you might to be diligent to get all oil in the area removed.

Apply enough J-B Weld into the recess area so you will be able to "carve" away the excess to provide a stop for the bell crank as though the aluminum frame had been machined the way you wanted in the first place. Position the frame with the bell crank end angled up and the trigger angled up so the J-B Weld doesn't flow toward the bell crank or bell crank axis.

Let it cure for 9-10 hours. This is important! Before that, it's too soft to work accurately, but after 15 hours it's completely cured and quite difficult to carve with a straight edged pointed tip Exacto knife blade.

Use the Exacto knife to remove the excess from the machined surfaces of the frame, then make a preliminary edge inside the bell crank recess to interface with the bell crank. You're now ready to carve the J-B Weld to precisely engage the bell crank to limit the trigger's forward overtravel.

When the firing pin is retracted in its normal position, the hammer comes to rest on the firing pin with its front face at about a 90 degree angle to the frame rails. When the slide is removed, the hammer rotates further forward of that point because there's no firing pin. You need something to hold the hammer in the same position it will be in when the gun is assembled.

For this, you need a "gauge" go fit between the frame and the hammer to substitute for the firing pin. Straighten a paper clip, bend it in half so the U in the middle is about the same width as the hammer. About 1/4" from the U, bend the 2 legs 90 degrees, then bend them 90 degrees down so they're parallel with the U and the gap between them is the same width as the frame where the hammer would strike the frame if the slide wasn't installed. Let this length extend for about 1/2" to 3/4" then bend the remaining length up to be a handle for the tool. A standard paper clip's wire thickness is just a shade too thin to hold the hammer exactly where it should be on my P-11. I put a small piece of masking tape on both sides of the hammer side of the tool (the U), and the two thicknesses on the gauge position the hammer perfectly!

Assemble the frame/transfer bar, paper clip, rubber band setup again. Use a rubber band to simulate the hammer spring so you'll be able to study the dynamic mechanism. Move the rear end of the transfer bar down so it's not engaged into the hammer, which can also be done by pulling the trigger until it releases. Notice that the trigger does not reset.

To see how much trimming of the J-B Weld you'll have to do, rotate the hammer back until it clicks when it engages the transfer bar. That's the reset point. Note the hammer face angle to the rails. You'll have to carefully trim the J-B Weld with the Exacto knife until the reset point is when the hammer rests against the gauge. As you get closer and closer to the proper adjustment, reassemble the pistol and check the trigger reset to make sure you haven't removed too much J-B Weld.

It's better to have too much trigger reset overtravel than not enough. Too much won't interfere with your pistol firing, but not enough could result in your not being able to reset the trigger.
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