Best way to raise mainspring tension?

armorer951 said:
Couple of thoughts about the light hammer strikes......

I didn't see in the previous posts where you mention if these light strikes are during SA or DA. I notice you have a trigger stop installed. Is it possible that the rebound seat on the hammer is hitting the hammer seat on the rebound during firing? Proper clearance between these two seats is necessary for the hammer to come fully forward when the trigger is pulled fully to the rear.
If the trigger stop is adjusted too far back, the trigger may be getting back far enough for it to cam off in DA and work in SA, but not far enough for the hammer seat on the rebound slide to be back and completely out of the way. You might double check to see that there is some gauge between the hammer seat and rebound seat when the trigger is pulled fully back, and the hammer is fully forward. Even slight contact here can impede the hammer enough to cause a light strike. It would be more of a problem during DA firing, as the trigger is not required to come back as far for the hammer to cam off, and move forward. (fire)

Also, I didn't read anywhere that you had checked the rear gauge (headspace) on the cylinder to confirm that it is within spec at .060"-.068". (closer is better, especially when fitting a gun you are using for target)
Click to expand...

These are all double action. I believe the clearance is good on the stop as I fired 100+ other rounds DA during the same match without issue (to say nothing of the hundreds I've fired before that) but I'll definitely check. The most interesting thing to me is that they all came out of the same box of American Eagle, and cartridges from every other box have lit off without issue.

I didn't even know about checking headspace - I'll have to look into that. The one thing I've noticed on this particular gun is that the ejector is fitted with an Aristocrat extractor rod collar and it seems to give the cylinder a tiny amount of front-to-back play. Not actually sure if that's the cause but I can wiggle the cylinder a tiny bit forward and back in when in lockup.
 
matteekay said:
So even with the pull I currently have, you think there may be ignition issues?
Click to expand...

Wolff Type II, reduced power, with a stock strain screw and Federal primers you're probably ok but this isn't engraved in stone. Bear in mind the length of "stock" strain screws seems to (randomly) vary somewhat. If you want to be sure use an 8-32 socket set screw instead of the (junk) stock strain screw. You'll have the ability to adjust plus the tip won't deform like the stock stainless strain screws do. Run the set screw in 'til you get the same gauge reading you had and then you can adjust (easily) as / if required. I file a small notch in the socket end so I have a reference for re-installing / adjusting.

IF you feel you must use a S&W strain screw the carbon steel (blued) ones are much better. Part of the "problem" with the Wolff mainspring is that the tip of the strain screw sits IN the springs' rib so the screw is effectively shorter. That along with the stock stainless strain screws' tips deforming as they're made from a poorly chosen material / heat treat combination.

Nice looking gun.
 
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Thank you!

This is one of the blued strain screws. I may do the set screw anyway just to be safe; should I try to file the tip flat? All the ones I've seen have the angled tip.
 
I just checked with feeler gauges and the end shake is .011" - .012". The cylinder touches the forcing cone when closed.

Seems a little far?
 
armorer951 said:
Also, I didn't read anywhere that you had checked the rear gauge (headspace) on the cylinder to confirm that it is within spec at .060"-.068". (closer is better, especially when fitting a gun you are using for target)
Click to expand...

Headspace is around .064". If I use washers to correct the excessive end shake, won't that increase the headspace? Should I just try to split the difference?
 
The cylinder should not "touch the forcing cone when closed". It should be at least .004"-.006" on a PPC style revolver firing lead bullets/wadcutters. This will help prevent the inevitable build up of shooting debris on the cylinder face from causing binding and rotation issues.

Adding shims to the yoke (or stretching) will move the cylinder back, closing the gauge in the rear (headsp) and opening the B/C gap. Keep in mind, some "end shake" (.001"-.002") is necessary to accomodate lubricants, and for the cylinder assembly to rotate and interface properly.
 
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Got it. Well, that sounds like a clear path, then!

I'm wondering if this all started when I had the cylinder cut for moons. I don't remember this much end shake play before that. Could just be my imagination, though.
 
Thanks for that.

I'm also realizing that I have a considerable amount of yoke endshake. I can't actually tighten the front side plate screw all the way without freezing the cylinder in place so I've been running it looser than I'd like. Definitely something I need to fix.
 
I'm going to try switching those around. Otherwise, I have a new set on order so I can file one down if necessary.
 
On the topic of how to raise mainspring tension - easy way to make strain screw longer. Chuck the screw upside down in a drill press and file the bottom of the head while it's spinning. Do a little, try it, do some more, etc. till you get what you want.
 
armorer951 said:
"...easy way to make strain screw longer."

You meant to say "shorter", didn't you? Shortening (filing) the screw will lessen the tension on the spring.
Click to expand...

No- I meant longer. By filing the underside of the head, the screw will go in further, thus putting MORE tension on the spring.
 
None of us is getting any younger.:mad:Besides, I have yet to meet anyone who is so good they can go through life without making a small error of some kind occasionally. I know I can't.
 
Updates:

- The sideplate screws had been mixed up. Must have happened a while ago, too. Anyhow, flipped them around and now I can crank down the front screw without it clamping on the yoke.
- I used a set screw and upped the draw weight to 9lbs 5oz. Honestly, it doesn't feel much heavier than it did in the high sevens and it should ensure ignition with factory ammo.
- I have the yoke and cylinder disassembled in anticipation of endshake bearings arriving tomorrow (thanks, Brownells!).

My only question now is whether or not I should install the (slightly) extended Power Custom hammer nose I ordered. I don't think there would be a concern with piercing primers but I'll have to take a look.

Thanks for all the help so far!
 
There is some good information in this thread. I am having light strikes in 2 of my Ks. Thank y'all for the solutions.
 
All this is good information but it reinforces the need to thoroughly check the gun before applying band-aid type fixes. The real problem was the mixed up side plate screws letting the crane and cylinder move forward until the cylinder contacted the barrel. So basically any change of mainspring, strain screw, rebound spring, or hammer nose were not necessary if the gun functioned 100% before. If one or more of these fixes were applied there was a very good chance that there would have been problems cycling the gun in D/A part way through the next match due to lead and fouling on the face of the cylinder. Not meant to point fingers just pointing out how important it is to start with the basics when diagnosing a problem.
 
series guy said:
All this is good information but it reinforces the need to thoroughly check the gun before applying band-aid type fixes. The real problem was the mixed up side plate screws letting the crane and cylinder move forward until the cylinder contacted the barrel. So basically any change of mainspring, strain screw, rebound spring, or hammer nose were not necessary if the gun functioned 100% before. If one or more of these fixes were applied there was a very good chance that there would have been problems cycling the gun in D/A part way through the next match due to lead and fouling on the face of the cylinder. Not meant to point fingers just pointing out how important it is to start with the basics when diagnosing a problem.
Click to expand...
Sorry, but... No. I still have a fair amount of endshake with the correct screws in the correct place.

Edit: Don't want to sound too harsh. Your point is valid, but that screw was not at all the cause of my issues.
 
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