Cylinder Lock Up

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ready05

Bearcat
Joined
Dec 8, 2007
Messages
40
When a new model blackhawk is locked up ready to fire and there is play in the cylinder movement, clockwise and counter clockwise rotation movement, is this a indication that the cylinder latch is not a tight fit in the cylinder notch? Would fitting a new and larger cylinder latch solve this problem? Thanks
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
Location
Star Valley, WY
Ruger's aren't set up all that tight. Mass production precludes such procedures. And, no, the slop is NOT an indication that the latch is loose in the bolt cuts. It's an indication that the latch is loose in the cylinder frame.
The "bit of slop" allows the cylinder to "self align" as the bullet makes the jump from cylinder throat to barrel.

Bottom line? Don't worry, be happy and go shooting.

The custom gunsmiths will tighten the lock up prior to lineboring the chambers. Freedom Arms makes "tight" guns as well.

flatgate
 

DGW1949

Hunter
Joined
Apr 10, 2005
Messages
3,638
Location
Texas
If you're talking a basicly new gun, don't worry....it is fine.
A bit of rotational "rocking" of the cylinder on a mass-produced revolver aint a bad thing at all.

And yeah....like Flatgate said, the "play" you describe is mostly found between the latch and frame.

If you keep the gun long enough, and if you fire it often enough, at some point you will be able to detect some wear on the sides of the latch. If/when that happens, simply replacing the latch will usualy suffice to restore the factory fit.....'cause frames are tougher than latches, so it's almost always the latch that wears.

Hope this helps.

DGW
 

JB696

Bearcat
Joined
Nov 1, 2006
Messages
45
Location
Ocean Shores, Washington
Actually, it is the tip of the pawl that makes tight lockup, not the cylinder latch. Changing the thickness of the cylinder latch will change the position of the cylinder at lockup and thus the barrel to cylinder bore alignment. When the trigger is squeezed all the way, the right side of the pawl is pressed against the right side of the slot in the recoil shield. The tip of the pawl on the left side is pressed against the flat on the ejector ratchet for that chamber. This pushes the cylinder counter-clockwise which forces the side of the cylinder notch against the latch. Which is in turn, pressed against the edge of the slot in the bottom of the frame window. This is what causes lockup. All of my Rugers have perfect cylinder/barrel bore alignment and tight lockup. The alignment was adjusted by varying the thickness of the cylinder latch. And the lock-up was adjusted by varying the thickness of the tip of the pawl. Sloppy lockup is common in production guns because it compensates for misaligned bores, crooked cranes, and wide tolerances in the various parts. It works (somewhat) thanks to the miracle of the forcing cone, which helps line up the bullet. :?
 

JB696

Bearcat
Joined
Nov 1, 2006
Messages
45
Location
Ocean Shores, Washington
The cylinder latch and pawl work exactly the same, single or double action. At lockup only one side of the cylinder latch is in contact with the side of the notch in the cylinder. It doesn't get jammed tightly into the notch. The cylinder rotation presses the latch against the side of the notch and the other side of the latch is pressed against the side of the slot in the frame. This is how all Ruger revolvers work. It doesn't matter if the tip of the latch that goes into the cylinder notch is thick or thin. The lockup is caused by the thickness of the tip of the pawl. The thickness of the latch only determines the location of the cylinder at lockup.

This can be easily seen by looking at an UNLOADED Ruger revolver. Look at the right side of the gun at the rear of the cylinder. On double action guns slowly pull the trigger back, on single action guns slowly pull back the hammer. The tip of the pawl will move forward and up until it contacts the ratchet on the extractor. It will turn the cylinder as it slides along the angled face of the extractor ratchet. Then, as the hammer is almost all the way back, and the cylinder latch has snapped into the cylinder notch, the tip of the pawl comes to rest against a small flat surface on the extractor ratchet. At full cock, the right side of the pawl is pressing against the right side of the slot in the recoil shield. The left side of the pawl, at the tip, is pressing against the flat on the extractor ratchet. This puts rotational pressure on the cylinder. So one side of the cylinder notch is pressed against the latch. The other side of the latch is pressed against the side of the slot cut in the frame.

Take a look at your gun in the fired, trigger released condition. The cylinder should have some rotational play in it. Then put a little pressure on the cylinder so that the latch is pressed over tightly against the side of the slot in the bottom of the frame window. You can see that if you change the thickness of the tip of the latch, you will change the position of the cylinder when it is at lockup.

When I "blueprint" an SP101, the first thing I set is the barrel to cylinder bore alignment. When looking down the barrel, a thinner latch will move the bore of the cylinder to the right. A thicker latch will move the bore of the cylinder to the left. Vertical alignment is trickier because it involves work to the the crane and the crane pivot hole. But rarely is there a vertical alignment problem. After the alignment is perfect I re-fit a new pawl. If the tip is too thin, the lockup will be sloppy. If the tip is too thick it will bind when the trigger is pulled all the way back (on a single action it would bind at full cock).

Adjusting the timing (not to be confused with the alignment) is next. But I won't go into that here as we are only dealing with the "lockup".

Precise fitting of the latch and pawl requires removing metal .001 at a time using #400 grit paper and a surface plate. I used to buy my latches, pawls and trigger plungers 20 at a time. Not only is this process very time consuming, but the precise fitting of the parts makes it real handy to have plenty of spares on hand.

When you pay $400 to a custom gunsmith to build you a gun, it's not all for the glass bead finish and the new sights. Much of the cost is for the hand fitting of the parts. Way, way back in the old days, some production guns actually came from the factory hand fitted. But time is money. That's why you can't buy a new Colt Python anymore. :(
 

JB696

Bearcat
Joined
Nov 1, 2006
Messages
45
Location
Ocean Shores, Washington
Jeez, what a long boring post I just made. There is a lot easier way to explain it. Take any model of Ruger revolver, for example. All of the cylinder latches they make for this model will be different sizes. If you measure the tip thickness of 20 parts, they will all be different. The ones I have on hand vary by as much as .004 of an inch. The same goes for the notches cut into the cylinders of various samples of the same model. Close, but not the same. The slots cut into the bottom of the frame windows also come in different widths. As well as the size of the ratchets on the extractor. It is not possible for any production company to make these machined surfaces exactly the same dimension, batch to batch, year to year. So what they do is make sure that the tips of all the cylinder latches are smaller than the notches cut into all of the cylinders. The slots cut in the frame are also made well larger than all the latches. Otherwise, it would take all day for a factory worker to match up the correct parts to assemble a gun. Some parts wouldn't fit together at all. Some guns would be incredibly sloppy. Some would be too tight. Rather than try to fit these four machined parts together, it is much easier to fit only one part, the tip of the pawl. The combined slop in the frame slot, latch, cylinder notches and extractor ratchets is all taken up at the pawl. Currently, some new Rugers come with a better fitted pawl than others. And many do come with tight lockup. It depends on how thick the tip of the pawl is. There we go. Simple, isn't it.
 

WOB

Bearcat
Joined
Feb 18, 2007
Messages
98
Location
Central Texas
What you say is true as far as it goes, but you didn't finish the story as it applies to the Blackhawk. When the hammer falls, the pawl retracts and the only thing holding the cylinder in alignment is the latch as the cartridge fires. That's why the custom smiths install fitted latches with stabilizer blocks to keep them from flopping around in the frame slot. Makes those expensive line-bored chambers stay lined up dead true with the bore.

WOB
 

JB696

Bearcat
Joined
Nov 1, 2006
Messages
45
Location
Ocean Shores, Washington
My single action rebuild experience is none. The pawl retracts from the extractor before the hammer comes down? Makes lockup kind of a problem doesn't it. Maybe the tip of the pawl should be a "V" shape which fits into a "V" shaped notch in the cylinder. So ignore my above posts unless you're working on a double action. :shock:
 

WOB

Bearcat
Joined
Feb 18, 2007
Messages
98
Location
Central Texas
Yes, the pawl is attached to the hammer near the hammer pin and it's motion follows the hammer movement. Lock-up tolerance is dependent on latch side-play and how well it fits the cylinder notches. By using a pawl that fits the notches closely and removing almost all of the side play with a stabilizer block in the frame, a snug lock-up can be achieved. Cylinder side-play is barely perceptable if everything is done right, yet function is still reliable. If the chambers are line-bored at the same time, you have the optimum set-up.

WOB
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
Location
Star Valley, WY
I agree with WOB. One must get the cylinder latch to firmly stabilize the cylinder then "line-bore" the cylinder prior to chambering. A task handled nicely by many custom gunmakers.

Exactly why a box stock Ruger costs mere pennies when compared to the "custom" stuff.

JMHO,

flatgate
 

REP1954

Blackhawk
Joined
Jul 21, 2008
Messages
959
I thought that I had read somewhere that when John Linebaugh rebuilds a revolver that he leaves it just a little loose not believing that a tight lock up was a good thing. I wish I could remember what I was reading at the time but I cant.
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
Location
Star Valley, WY
I think you've slightly misquoted Mr. Linebaugh. I've handled and fired a few of his guns and they are set up rather "tight". I believe your "quote" was made in reference to the Ruger way of assembling S.A. Revolvers.

I have a boat load of Rugers and most are VERY GOOD shooters and the rest are Good. I've had two "dogs" over the years and simply traded them off for something else....

flatgate
 

REP1954

Blackhawk
Joined
Jul 21, 2008
Messages
959
I never misquoted Mr. Linebaugh. I never said that he said it. I only stated that I had read that he leaves a little play in the cylinder.
 

REP1954

Blackhawk
Joined
Jul 21, 2008
Messages
959
Well actually I was hoping that someone else might have also read the same thing and been able to help with where it was but I dont think thats going to happen now. But feel free to PM me if you have any info.
 

REP1954

Blackhawk
Joined
Jul 21, 2008
Messages
959
Flatgate, It seems that for some reason you think that I believe that John builds his guns that way. Well I dont. I found it humorous that someone would write such a thing. But I guess you dont find it humorous. I have been to Johns website many times in the past and have read just the opposite of what I was pointing out in many other places. So sir smile and have a nice day! :)
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
Location
Star Valley, WY
Nope, I'm just countering the mere thought that John might even consider such a thing........

No offense intended.

Cheers,

flatgate
 

Carry_Up

Single-Sixer
Joined
Dec 22, 2007
Messages
374
Location
Phoenix, AZ
I'm no genius at revolver tuning, but I think there are some incorrect assumptions that need to be pointed out. The original post asked about cylinder lockup, the amount of rotational slop existing in the cylinder after the gun is cocked. The question was, is that slop a problem? And the answer is - maybe or maybe not.

Lots of excitement can be generated by folks who claim they can take up all the tolerances in cylinder rotation by painstakingly changing the pawl thickness and the hand dimensions. I think that all that painstaking work is of no practical use except for show and tell. The incorrect assumption here is that a revolver with no cylinder movement is more accurate, and somehow better and more reliable once all this work has been done. Not so - in my personal experience. Not only that, but normal use will easily wear in those carefully selected parts because they are small bits of metal that cannot withstand many rounds of hot ammunition without deformation. A number of experienced revolver smiths have weighed in on this topic on this very forum. They have repeatedly pointed out that the cylinder and forcing cone are self-aligning if there is a small amount of play in the cylinder.

Furthermore, the claims are that alignment problems are eliminated. Also incorrect. Fussing with pawl thickness and hand thickness might result in one or possibly two chambers lining up exactly. But since there are boring tolerances on the chambers, you have just produced a revolver that "locks up tightly" but incorrectly on all the other cylinders. The only exceptions to this manufacturing reality are when the chambers are line bored with the barrel axis at the cylinder's lockup position. And only a few manufacturers do it that way and at a hefty cost.

One more consideration - reliability. All our careful fitting and choosing of parts down to the last .001" to achieve this amazing no movement lockup situation has to result in greater sensitivity to dimensional changes related to heat as well as sensitivity to powder fouling and debris. That translates into intermittent problems with that action. So where does that leave us?

We know the main critical parts of the revolver that must be right for the gun to shoot. Of primary importance is having the cylinder face parallel to the forcing cone face. And having a smooth and correct angle on that f/c. A nice crown will improve a bullseye gun. And, obviously on a D/A revolver, the cylinder must lock up before the hammer falls. The rest is just show and tell. My personal opinion, of course.

Carry_Up
 

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