686, trigger shims and carryup

[jh9]

So I've got a 686 that I've had for years. Haven't shot it in awhile and when I started looking at it I noticed that it doesn't carry up in slow DA when pulling the trigger with my left hand. Right handed everything's fine. Left handed the hammer drops before the stop clicks into place.

Problem is I'm a lefty.

I ordered a set of Power Custom trigger shims (.002) since I noticed there's some wear on the left of the trigger (through the case hardening). I put two of them in (between the frame and trigger) and still get some slop and it has the same timing problem.

Kind of wanted to post as a sanity check before trying 3. Is there something else I should be doing? The Kuhnhausen manual doesn't have anything (actually the only thing it has on timing is "hand width is important"). I vaguely recall this being referred to as "singing" but a google search doesn't seem to match what I remember.

Thoughts?

[bountyhunter]

All SW revos develop carry up "failure" over time simply from wear of the components. That's why they make oversized hands and oversized cylinder stops. To fix the carry up problem, an oversized hand will probably do it but tey do need to be fitted and I also balance the ratchets when I fit a new hand. I have had to do this on multiple SW's over the years. The "left versus right" thing probably means you get a shade better trigger actuation pulling from the right because of wear but the fix is not shims (IMHO).

Edited February 7, 2015 by bountyhunter

[Toolguy]

I have come up with 2 ways to field fix this. These are not the recommended thing to do, but can get you by until you get a wide hand ordered in and fitted. They are to be viewed as temporary only. Both of these simulate having a wider hand. In either case you may need to use a hand window file to widen the window towards the center pin to get enough movement. You usually have to do this anyway to install a wider hand.

1 - You can bend the hand slightly inward towards the center pin. Remove the trigger/hand assy. from the frame. Keep it all together and bend the hand inward (to the left) with your fingers. This will put the tip of the hand closer to center, slightly advancing the timing. When you reassemble and pull the trigger you can feel (and see with the sideplate off) the hand going out around the ratchet when the cylinder locks up. This bends the hand pivot pin ever so slightly and allows the hand to be leaning to the left a little.

2 - You can twist the hand counter clockwise (looking down from the top) with pliers while holding the trigger in the other hand or a vise. We are talking tiny amounts in both cases so don't get carried away with it. If you go too far, just undo it a little. As with most gunsmithing, these are a try and fit proposition. The hand needs to run freely without binding, yet still do the job.

[PatJones]

Sing refers the ability of the hand to move freely in its window. If the hand is free to move it will freely ratchet over the extractor and sing, if it's not free to move it will be silent. As you've discovered the trigger is operated a bit differently by each of the shooters hands, so there is left and right sing. It is adjusted by bending the pin on the hand.

Several things can cause a failure to carry up including a bent ejector rod and a bent yoke. If you need a new hand they often require some fitting. If you don't have the tools and experience, you might do best to search out a gunsmith who does.

[jh9]

Thanks for the input guys.

This will be the 2nd hand I've put in this gun. I was hoping maybe the slop in the trigger would be a magic bullet and I wouldn't have to do the "take apart, stone, put back together, rinse repeat" dance.

I checked my parts box and I've got a 686 hand (not the oversize).

Not this one:

http://www.midwayusa.com/product/888914/smith-and-wesson-hand-s-and-w-581-3-586-3-681-686-oversize

This one:

http://www.midwayusa.com/product/745011/smith-and-wesson-hand-s-and-w-242-331-332-386-386pd-581-3-586-3-619-620-686-581-586

The one that's in there now I'm pretty sure was oversize and just hitting the bevel like in the midway video on youtube wasn't going to cut it. I had to take metal off like the top quarter inch of the hand's body (making it thinner side to side not shorter) to keep it from sticking to the ratchet when the trigger was pulled.

I guess I took too much off since I only got like 3k of warmish .38s before I'm back to square one?

This is the video I was talking about:

Edited February 8, 2015 by jh9

[jh9]

This bends the hand pivot pin

It is adjusted by bending the pin on the hand.

Hm.

So should I try this in lieu of using my only spare or just go ahead install the (not oversize) spare and follow the directions in the video to the letter?

The part about filing the window in the frame is new to me. I'm starting to get the impression that the oversize parts are not just "a bit more metal" but part of more extensive work.

Did I just use the wrong part to start with? If I'm not going for an extreme action/lockup job then the regular not-oversize part is the one I should have used to begin with?

[PatJones]

Adjusting sing is different than adjusting carry up. Sing has to do with the hand moving freely in the window.

Have you confirmed that the yoke and ejector rod are straight. The yoke requires a gauge to measure. These are done before replacing parts. If you don't have the tools, find someone who does.

[Toolguy]

It's difficult to diagnose some things without being able to look at the gun. It sounds like the ratchets may be worn a little. That is normal for a gun that gets used. The wider hand is made to correct that problem by compensating with more material on the hand to replace the material worn off the ratchets. Over the years I've seen a few new guns that needed that too, they were made out of spec.

In your case I would try bending the hand inward and see if that helps. With the sideplate off, watch the hand pushing the ratchets as it goes through the cycle and see what it's doing. Then watch again after an adjustment. This helps to visualize and understand what is going on inside the gun during a trigger pull. Plus, you will see what your particular gun is doing. Once you understand how the parts work in relation to each other, you will clearly see when something is working correctly or not.

[bountyhunter]

This will be the 2nd hand I've put in this gun.///////

With all due respect to Mr Potterfield in the video, he is grossly oversimplifying a fit process in a way that could really lead somebody to screw up a gun. If you did put in an new oversized (properly fitted) hand and needed another one in a relatively short time, that tells me that the hand probably wasn't fitted right or the ratchets need balancing. Check carry up on all cylinder positions and note how much disparity there is between the "best" one and worst. If there is a fair amount of difference, the hand alone won't fix it. The hand has to be fitted to the "loosest" ratchet and then each other ratchet in turn is fine tuned to the new hand. You end up with perfect carry up on all positions and won't need a new hand for a long time. I recommend gunsmith fitting if you have not done this before.

Edited February 8, 2015 by bountyhunter

[bountyhunter]

This bends the hand pivot pin

It is adjusted by bending the pin on the hand.

Hm.

So should I try this in lieu of using my only spare or just go ahead install the (not oversize) spare and follow the directions in the video to the letter?

The part about filing the window in the frame is new to me. I'm starting to get the impression that the oversize parts are not just "a bit more metal" but part of more extensive work.

Did I just use the wrong part to start with? If I'm not going for an extreme action/lockup job then the regular not-oversize part is the one I should have used to begin with?

Understand: there are three primary wear surfaces:

1) The hand itself

2) The frame window edge farthest from the gun center

3) The ratchets

Installing a new standard hand addresses #1, but in my experience, a standard hand alone doesn't usually fix it. You ned an OS hand cut down to fit. A standard hand runs about .092 ballpark and OS hand is about .099" ballpark if memory serves.

The part about filing the window in the frame is new to me.

I never had to file one because the wear on the window edge always opened it up enough. But if you have to file it, only file the edge nearest gun center. The other edge is the one that wears naturally.

Edited February 8, 2015 by bountyhunter

[Toolguy]

Lots of good advice here. There is kind of a long learning curve on revos because there are so many interrelated nuances involved. Most of the fitting type things have to be within a thousanth or 2 to work properly. The best way to get the job done is to take it to someone with a known good rep on revos or go learn from one of those guys. You pay for your education one way or another. I trashed my fair share of parts learning on my own guns. The timing thing takes a bit to wrap your head around. As has been mentioned before, there can be more involved than just the hand and the ratchets. Each gun is an individual case. I don't want to sound elitist or discourage anyone from doing their own work, but something that looks simple can turn into quicksand.

[PatJones]

If you have to balance the ratchets, it involves fileing the tighter teeth. It's really easy to file too much and then you need a new extractor.

[azfred]

Great thread!

[bountyhunter]

If you have to balance the ratchets, it involves fileing the tighter teeth. It's really easy to file too much and then you need a new extractor.

Couldn't be more true.

You need special files, and have to be very careful. I mark each ratchet on the top with a sharpie to make sure I know which one I am working on. I also use a sharpie on the surface of the ratchet that rubs against the hand to see exactly where the highest spot is to make sure I only take metal off where needed.

I always remove the hammer and rebound slide when fitting a hand to be able to better feel the fit against the ratchets.

[jh9]

When I put the new hand in, I also put a new extractor. It's a 686-5 so it's got the new(er) square extractor without the pins. I didn't do anything to it in terms of fitting. I re-read my OP and left that out. Sorry.

The carryup is the same on all 6. Like, identical. Just *barely* not enough rotation to get the cylinder stop to click into place before the hammer falls.

Works as expected when pulling the trigger with the right hand (cylinder stop clicks into place, then just a bit more hammer movement to the rear before it falls.)

It's almost textbook perfect right handed. Left handed, though, it's just a shade like barely really alllmost right but no.

Grr.

[jh9]

Adjusting sing is different than adjusting carry up. Sing has to do with the hand moving freely in the window.

Have you confirmed that the yoke and ejector rod are straight. The yoke requires a gauge to measure. These are done before replacing parts. If you don't have the tools, find someone who does.

The ejector rod is straight. I don't have the tools to do the yoke.

[toothguy]

When I put the new hand in, I also put a new extractor. It's a 686-5 so it's got the new(er) square extractor without the pins. I didn't do anything to it in terms of fitting. I re-read my OP and left that out. Sorry.

The carryup is the same on all 6. Like, identical. Just *barely* not enough rotation to get the cylinder stop to click into place before the hammer falls.

Works as expected when pulling the trigger with the right hand (cylinder stop clicks into place, then just a bit more hammer movement to the rear before it falls.)

It's almost textbook perfect right handed. Left handed, though, it's just a shade like barely really alllmost right but no.

Grr.

Where your action is now sounds about like how my Bianchi 686 is. I have it set right at the edge because it helps my accuracy at 50 yrds. I'm right handed so I didn't notice a problem until the weak hand only stage of the Practical. I got around the problem by using the pad, not the joint, of the finger and focusing on pulling the trigger straight back. I'm thinking that you may need to adjust yours so it's a little to advanced with the right hand so it's correct with the left.

You might also try to contact Matt Griffin on this forum or on his website. He is an excellent revolver shooter and also left handed, he may have some ideas about this problem.

Edited February 9, 2015 by toothguy

[PatJones]

When I put the new hand in, I also put a new extractor. It's a 686-5 so it's got the new(er) square extractor without the pins. I didn't do anything to it in terms of fitting. I re-read my OP and left that out. Sorry.

More details about this please. The extractors are fit to the gun at the factory. For a long time it was a factory only part.

Was the extractor factory new or used? What was your process of installing it? It should have been too tight to work with a standard hand if new. Did you narrow up the hand until it worked? The correct process is to cut each tooth until it fits a standard hand. The factory uses a hardened cutting hand for this.

[jh9]

When I put the new hand in, I also put a new extractor. It's a 686-5 so it's got the new(er) square extractor without the pins. I didn't do anything to it in terms of fitting. I re-read my OP and left that out. Sorry.

More details about this please. The extractors are fit to the gun at the factory. For a long time it was a factory only part.

Was the extractor factory new or used? What was your process of installing it? It should have been too tight to work with a standard hand if new. Did you narrow up the hand until it worked? The correct process is to cut each tooth until it fits a standard hand. The factory uses a hardened cutting hand for this.

So far as I know this doesn't apply to the square (non-pinned) extractors from the early 90s (post Tomkins-era CNC) onward? My understanding is the old, round, pinned extractors were labor-intensive to fit. The newer ones not so much.

From memory I dropped the new extractor in first and it still wouldn't carry up with the old (worn) hand. The bearing surfaces on it definitely weren't way oversize.

edit: it was a new part, purchased from midway

Edited February 9, 2015 by jh9

[PatJones]

I found it was still the case with a 627 I worked on a couple years back.

[jh9]

Where your action is now sounds about like how my Bianchi 686 is. I have it set right at the edge because it helps my accuracy at 50 yrds. I'm right handed so I didn't notice a problem until the weak hand only stage of the Practical. I got around the problem by using the pad, not the joint, of the finger and focusing on pulling the trigger straight back. I'm thinking that you may need to adjust yours so it's a little to advanced with the right hand so it's correct with the left.

Based on what toolguy said in post 8 this may be worth a shot. I should probably consider this hand toast anyway, so not much to lose.

[jh9]

I found it was still the case with a 627 I worked on a couple years back.

Hm. Was it a new post CNC / post MIM gun?

[PatJones]

Yes.

[jh9]

Yes.

Good to know.

I wonder if the factory does extractors like hands, in that some are intentionally *way* oversized (like they used to be) and others aren't.

[bountyhunter]

When I put the new hand in, I also put a new extractor. It's a 686-5 so it's got the new(er) square extractor without the pins. I didn't do anything to it in terms of fitting. I re-read my OP and left that out. Sorry.

The carryup is the same on all 6. Like, identical. Just *barely* not enough rotation to get the cylinder stop to click into place before the hammer falls.

I'd wager half the used SW revos out in the world do the same thing. As long as you get cylinder lock on a normal pull, it's fine. Also: a loaded cylinder is heavier and has more rotational inertia than an empty one and the momentum helps carry it to lock. Your gun is probably OK to shoot, but fitting a new oversize hand should restore "like new" carry up.

Edited February 9, 2015 by bountyhunter