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matteekay

Time for a new crane I guess

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I had an interesting reload while competing at the USPSA state championship last weekend. Running into the last arrays on my last stage (because of course), I popped the cylinder open, ejected a spent moon, and went to drop in a new one only to find that I didn't have a cylinder any more. After taking the zero on the stage and finding all of the pieces of my gun, we figured out that the crane slipped past the yoke screw (S&W 627 with the new plunger-style screw) and out of the gun. It looks like there were a few contributing factors - the screw had loosened somewhat, the plunger/spring had separated from the screw, and the crane was sporting this shiny divot: 

 

48761104501_7c87df050a_c.jpg

 

I've been experimenting at home and I can get the crane to repeat this by loosening the yoke screw two turns, opening the cylinder all the way, and then pulling it straight out of the gun.

 

I've already ordered new yoke screws and I'm looking into sourcing a new crane now (the new style is proving hard to come by). If anyone has any creative ideas on how to spare this crane I'm all ears, but I don't see a way to fully guarantee it won't happen again.

 

Does anyone know what would cause this damage to occur?  

 

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Looks buggered.

 

First thing I would do though is replace your yoke screw, and stone off that burr on the end of the crane.

 

The likely scenario is a trip back to smith though, it looks pretty grooved.Smith wont sell you one, so might as well just send it back in - or try and get lucky on the used market. 

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Cranes are individual to each gun, a fitted part. I would just stone off that spot created by the old screw and fit a solid screw. Shouldn’t have that issue with a solid screw. 

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If you shoot a lot, its bound to happen to you sometime in life. Its a fact of life with those sprung yoke screws. I don't know what  the red coloured sealer is that S&W use on the yoke screw but however if its gone then I replace my screw with a new one. The  damage on the end of the yoke can be dressed off with a file. Rather than mess around trying to get the yoke replaced you can weld them up and dress them down. 

 

 

 

 

 

 

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15 hours ago, MWP said:

Cranes are individual to each gun, a fitted part. I would just stone off that spot created by the old screw and fit a solid screw. Shouldn’t have that issue with a solid screw. 

Where would one acquire a long yoke screw for fitting?  I'd love to have all of my smiths fit with a full length yoke screw.  Having experienced the dreaded "V' myself, I'd love to circumvent the issue before it returns.    

Jason

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It used to happen with my 686SSR until I got a tip from a revo GM who learned it from Randy Lee @ Apex.  Get rid of the yoke screw spring, replace the stock plunger with a solid rod, shape the rod tip to match the original, and grind the length until you get the proper length for a tight fit without being too stiff.  Never had another problem.  I think I used a correct diameter drill bit to create the new rod.

 

image.png.22b71dc462ff372d695f9aea13c1338a.png

Edited by Tampa-XD45

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2 hours ago, Makicjf said:

Where would one acquire a long yoke screw for fitting?  I'd love to have all of my smiths fit with a full length yoke screw.  Having experienced the dreaded "V' myself, I'd love to circumvent the issue before it returns.    

Jason

I got mine at the hardware store. 

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18 hours ago, pjk said:

If you shoot a lot, its bound to happen to you sometime in life. 

Correction: *If you reload weak hand a lot, it’s bound to happen to you. 

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Or you don't have the proper screwdriver to put it back in tight after cleaning.  Think I got nailed for 160 seconds in penalties when it fell out at a match right at the first reload of a stage. ouch

 

I do remember everyone else heading over to the safe table to make sure theirs were tight.

 

ps thanks MWP for the tk prize moons envelope last week. 🙂

Edited by MikeyScuba

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Very timely post, I just came here looking for a fix to the exact same problem.

One would think Smith would be smart enough to recognize it’s a stress point, and it’s a lot easier to replace a shorn-off yoke screw than a crane, and thus make the plunger from a softer steel.

The use of shear pins to prevent damage to critical parts is kinda Mechanical Design 101.

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2 hours ago, FWSixgunner said:

Very timely post, I just came here looking for a fix to the exact same problem.

One would think Smith would be smart enough to recognize it’s a stress point, and it’s a lot easier to replace a shorn-off yoke screw than a crane, and thus make the plunger from a softer steel.

The use of shear pins to prevent damage to critical parts is kinda Mechanical Design 101.

It is not due to a mechanical design flaw, it is on purpose, it saves s&w time and money by not having to fit the screw to the crane by using the plunger with spring. It's ALL about the $$$ they used to be solid.

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4 hours ago, mchapman said:

It is not due to a mechanical design flaw, it is on purpose, it saves s&w time and money by not having to fit the screw to the crane by using the plunger with spring. It's ALL about the $$$ they used to be solid.

That and the design team is probably not all that aware of what we are doing to these guns. 

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That and the design team is probably not all that aware of what we are doing to these guns. 
Right? They probably expect people will put the moon clip in with their right hand.

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Right? They probably expect people will put the moon clip in with their right hand.
You sunnuva.... Lol.

Toolguy has saved the day! I'm also going to make a solid retention screw per everyone's suggestion.

It really is a bummer that Smith invented a new point of failure just to save time/money on assembly.

Sent from my Pixel 3a XL using Tapatalk

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16 hours ago, MWP said:

That and the design team is probably not all that aware of what we are doing to these guns. 

And if they did they would probably never give us a warranty!

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I wonder if Jerry M's revos have ever had that problem. As much as he shoots, I would bet yes...and S&W is probably aware of it...but, like vehicle recalls, if it only affects a small segment of users, and will cost $$$$$$ to correct, the correcting costs outweigh the manufacturing costs to do it right the first time.

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On 9/20/2019 at 11:03 AM, MWP said:

Correction: *If you reload weak hand a lot, it’s bound to happen to you. 

 

17 hours ago, GrumpyOne said:

I wonder if Jerry M's revos have ever had that problem. As much as he shoots, I would bet yes...and S&W is probably aware of it...but, like vehicle recalls, if it only affects a small segment of users, and will cost $$$$$$ to correct, the correcting costs outweigh the manufacturing costs to do it right the first time.

 

JM reloads with his strong hand. Last best guess I've heard is that there is about a 50-50 split among shooters? 

 

Timely thread for me too. I'm sure S&W has replaced enough cranes to know that they are a weak spot, do not know if they care one way or the other. I like the solid screw idea but am wondering if there is someone crafty with a tig welder to send the crane to.  

Edited by IHAVEGAS

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Don't file or stone and remove the damage.

Take a small hammer or hammer and punch and try to put the metal back in the damaged area GENTLY. You can then touch up with a stone if there is any high spots.

If really bad you can take a small center punch and on the back side(the flat side) and center punch both side of the damaged area and that will move some metal back into the damaged area and fill it in. Don't get carried away and bend the crane.

After a few repairs it might have to be welded and any decent TIG guy that has SS experience can touch it up.

 

What causes this? 

Usually a loose yoke screw.

I have seen several yoke screws that the plunger is stuck in. Hard to tell by looking but measuring them shows they are stuck. This can cause the damage or even let the cylinder fall out while the yoke screw is tight.

I always put a drop of oil on the plunger when I do a compete cleaning(which is not that often).

Yoke screws are cheap and do need to be replaced every once in a while.

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Don't file or stone and remove the damage.

Take a small hammer or hammer and punch and try to put the metal back in the damaged area GENTLY. You can then touch up with a stone if there is any high spots.

If really bad you can take a small center punch and on the back side(the flat side) and center punch both side of the damaged area and that will move some metal back into the damaged area and fill it in. Don't get carried away and bend the crane.

After a few repairs it might have to be welded and any decent TIG guy that has SS experience can touch it up.

 

What causes this? 

Usually a loose yoke screw.

I have seen several yoke screws that the plunger is stuck in. Hard to tell by looking but measuring them shows they are stuck. This can cause the damage or even let the cylinder fall out while the yoke screw is tight.

I always put a drop of oil on the plunger when I do a compete cleaning(which is not that often).

Yoke screws are cheap and do need to be replaced every once in a while.

 

Interesting, I had been thinking the same thing (hammering).

 

BTW, what’s the thread pitch of a yoke screw?

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On 9/20/2019 at 11:03 AM, MWP said:

Correction: *If you reload weak hand a lot, it’s bound to happen to you. 

 

I reload weak-hand and have NEVER had it happen.  I have certainly seen it happen to others, though!  My theory is that some guys are just rough in handling their guns.  They're the same guys who slam their cylinders shut with lots of force and then have problems with peened stop notches, etc.  (Habits that are developed early on are hard to break.) 

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On 9/20/2019 at 8:15 AM, Tampa-XD45 said:

It used to happen with my 686SSR until I got a tip from a revo GM who learned it from Randy Lee @ Apex.  Get rid of the yoke screw spring, replace the stock plunger with a solid rod, shape the rod tip to match the original, and grind the length until you get the proper length for a tight fit without being too stiff.  Never had another problem.  I think I used a correct diameter drill bit to create the new rod.

 

image.png.22b71dc462ff372d695f9aea13c1338a.png

 

This!  (Or if you can make a solid yoke screw, that would work fine, too.)

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