S & W 642 Hand Torsion Spring :-)

[905 Newbie]

Hi,

I have done over a dozen Ruger Mark II trigger jobs and rebuilt a few 380 semi-automatics and, for the life of me, I can’t figure out how this spring is supposed to go in or how it functions! :banghead:

I also spent more time searching the net and this board than the job should have taken.

Can someone who is familiar with the reassembly please tell me, in simple terms, which position the spring should be in?

It has two coils, a long end and a short end so, looking at the trigger flat on the bench; the spring can be positioned [to start with], in any of the following four positions

__o___ ___o__ -----o--- ---o-----

All of the following questions are pretty much the same; but, just phrased differently, to help me get a clear answer.

1. Which way does it go in? Loop up or down?

2. When done, should the “loop” of the spring be sticking out to the right of the trigger?

3. Which end touches the smaller of the two pins in the Hand and which end is “pressured off of the trigger”?

4. Does the end that touches the smaller Hand pin, go above it or below it?

5. Isn’t the point of this spring to put tension on the Hammer Sear and keep pressure on it to the left? Or am I just not getting it; because I got the gun apart and back together [after finding the spring] and the pressure was to the right – the gun would not function.

I can’t figure out how to insert and “shape” the spring to create the proper “tension direction”.

I hope I explained this well enough. Other than blurry part schematics, I could find no internal pictures to guide me.

I really appreciate your help.

Thanks,

Craig

 

[Jim K]

Answered on the Firing Line site.

Jim

 

[Old Fuff]

With the trigger facing to your right, notice there are two pins located just under the trigger's pivot hole. One is in front of the pivot hole, and the other is behind it. There is a 3rd. pin located below these two, but it can be ignored.

The spring is held in place by a pin going through the coils and the rear hole (behind the pivot hole.) The shorter leg should be pointed toward the front, and rest on top of the pin in the front hole.

This position would be correct according to your diagram: ___0_

There are two pins in the hand. The hand pivots on the larger one, and that pin goes through a hole at the far rear of the trigger. There is a slot in front of this hole on the right side of the trigger. The smaller of the two pins in the hand goes into this slot.

The longer leg of the spring should rest on the top of the smaller hand pin.

To assemble the hand into the trigger: Insert the larger pin in the hand into the trigger, but do not push it far enough so that the smaller pin sticks through into the slot in the center of the trigger.

Using a small, thin bladed screwdriver or punch, lift the spring's longer leg until it is above the smaller pin on the hand. When this is accomplished, push the hand onto the trigger the rest of the way, and then release the spring's leg so that it rests on top of the smaller pin in the hand.

1. The loop goes up.

2. No, the loop should be inside of the trigger and retained by a pin going through it.

3. The longer leg touches the top of the smaller pin in the hand. The shorter leg presses on the top of a pin in the trigger.

4. The (longer) spring leg should rest on the top of the smaller pin in the hand.

5. This spring has nothing too do with the sear (located in the hammer face) or any other part accept the hand. When correctly assembled the spring will push the hand forward.

Some people should have their fingers cut off if they are caught touching a screwdriver...

 

[905 Newbie]

You both had me until...

Never mind...just figured it out.

No extra pin and does go in that "slot", right?!

Like everyone else said..."easy but really hard to explain!"

Thanks guys,

Craig

 

[orionengnr]

anxiously watching this one...

as I am going to take apart my 340 one fine day and see if I can l "smoothen" and lighten the trigger pull. Prolly have to order some springs first...(shameless request for recommendations)

And if I get cocky, it will be time to replace my 37s hammer with a bobbed model and do some spring-trickery with it.

Unless you think the 37 should come first...

I have Mr. Miculek's DVD and Mr. Kuhnhausen's book. (Guys on SWforum recommended them.) Any further reference material you can suggest?

Thanks, Rich

 

[Old Fuff]

Houston, we have a problem...

The instructions I posted above are for Smith & Wesson's that were made before the new MIM lockwork was adopted. All of the shop manuals (including Jerry Kuhnhausen's) and the various other sources for exploded view drawings (such as found at www.e-gunparts.com) are for the older guns.

I have made a point to avoid working on the newer guns after going through one of the last model 19's. Internally, the new guns are the same in some ways, but different in others. Therefore the older rules and procedures don't necessarily apply. I will happly let others work on the new ones. This old dog has no intention trying to learn new tricks.

Possibly Smith and Wesson might have updated exploded view drawings on their website at www.smith-wesson.com

But don't make the mistake of following the instructions for the older revolvers until you are sure they still apply.

 

[Jim K]

OK, guys, sorry about the misinformation. Both Fuff and I were thinking of the old S&W system, not the new one.

That hand spring still goes into the slot in the back of the trigger, short end forward and loop up. That has not changed. But instead of a pin to hold it in, the short end goes into a hole in the trigger; that hole and a circular opening provide the tension. It is above the place where the trigger lever goes in. You may have a time finding that hole (I did) but it is there; you can find it with a paper clip. When installing the spring, you may have to feel for it with the spring held by tweezers. That hole comes out into the area where the "L" opening is. I am not sure of the purpose of that "L" opening; the spring does NOT go through it.

Once the spring is in place, the rest of the assembly goes the old way. Push upward on the long end of the spring, and hold it while installing the hand, making sure the end of the spring goes ON TOP OF the short pin of the hand.

FWIW, both the spring and the trigger lever used to be held in by pins, but one advantage of MIM is that they were able to make that trigger so precisely without machining that they can simplify the whole thing. It is not bad, just a bit different.

I am sure Old Fuff remembers when they used a coil spring and a machined lever that pivoted on its own pin. The torsion spring was an improvement on that, and a lot cheaper. The new system is even cheaper and simpler.

Jim

 

[Old Fuff]

Yes indeed, The Old Fuff remembers the old lever-and-coil-spring tension system for the hand, but I actually prefered it. The lever put more even pressure on the hand's pin, and I could tune the tension by changing out different coil springs.

Granted it was more expensive and more complicated. And if dirt got between the coils of the hand spring it could really mess things up.

But it worked great when you were going for the very best in a double-action.

As for the new ones... :banghead: