Fitting an oversize cylinder catch, where to file?

[GWW]

I'm in the process of fitting an oversize cylinder catch in a 27-3, I have a perfect fit to the cylinder and the window in the frame, it locks up very nicely, but during a pull of the trigger the ball drops below the window in the frame about .002. I'm not sure where to remove material to keep it from dropping below the window, the Recovery Surface or the Bevel as pointed out in the attached photo? Thank you in advance!

 

[Hondo44]

It would be the recovery surface: the trigger extension that contacts it there will not be able to push the ball below the window so far.

However, a low ball is not an issue if it's working fine as is, so there's no need to "fix" it.

Recognize that the more you remove from the recovery surface, the later the ball will clear the cyl notch (in the extreme the cyl will bind on cocking) and the earlier the bolt will pop up against the cyl. Also the line scribed on the cyl surface between the notches gets longer.

 

[GWW]

Going by the FAQ post made by 500 Magnum Nut --> FAQ at no time should the ball drop below the window otherwise it can get hung up. A copy and paste of his text from that post;

"Make sure that when the trigger pulls it down, that it does not pull the ball out of the frame window. If you leave it set where the ball drops below the opening, it can get offset to one side and hang up inside the frame.

When originally fitted, the stop is timed so that at no time the top of the ball drops below the edge of the window in the frame. If it does, it can stick in the down position."

I have one shot at this before ruining the part, now so close with everything else fitting perfectly with such a wonderful lockup achieved I hate to ruin the catch and have to start over.

Wouldn't cutting the Bevel back also achieve the same? My concern was and is, cutting the Bevel back, does that effect timing elsewhere during the cycle? Same goes with the Recovery Shelf, why they named it the Recovery Shelf might give a hint but that's knowledge lost to me. I understand each part has an effect on how another part operates and timing is critical, one part out of spec can have a negative effect, two or more and you have stacking. These are finely designed intricate pieces, very intriguing to me and I love to find out how machinery works, always have. It's one of the things that drew me to firearms as a youth and started me tinkering with them, I've always done as much of my own smithing as I can, a few times it bite me but more times then not I've made my own repairs, even those times I failed I gained more knowledge.

Just last night I discovered there is the book by Kuhnhausen, the 5th edition S&W revolver shop manual, I'll get one ordered but in the mean time I was hoping a S&W smith might answer my question, like to finish this project in the next couple days.

A little of my background, my Father was a tool and die maker, he made prototype parts and tooling for Smith Corona typewriters, tiny parts... He taught me as a lad how to use and read a micrometer, gave me one of his spares to learn with, he also taught me how to read and draw blueprints. From there I always had an interest in anything mechanical. At an early age I wanted to be a machinist like my Father, my Hero. I took two years of Machine Shop trade school classes but as a teenager with a drivers license my passion also turned to hot rods. I ended up working on cars all my life but still have that machinist passion, my machinist skills came into play when rebuilding engines and transmissions, an overlap of both passions. Now that Dad has passed, I have his machinist tools along with those I used on the job. And now retired, I love to spend time tinkering in my shop. Taking an out of time 27, installing a new oversized hand and cylinder stop to make it perfect has been very, very satisfying.

 

[armorer951]

Fitting new parts is always a challenge, and is as you stated, very rewarding when you get it right. Kuhnhausen's book provides a lot of great information and data along with some very good illustrations. Members on this forum are also a great source of info regarding any S&W topic you can think of.....a great group of folks here.

I agree with Jim (Hondo44) concerning how to proceed, especially if the gun will be a range gun and not carried or used for defense. There is a good reason for leaving it where it is in terms of the stop ball going slightly too far down, as long as the gun is functioning correctly. The reason is that the interface between the trigger hook and the bevel of the stop are now at a point where the longest life can be expected from the parts. Removal of more material now, either from the point of the bevel or the recovery step, for the purpose of meeting an arbitrary fitting requirement would only shorten the lifespan of the stop.

Another aspect of fitting a new oversized stop is the resulting barrel/cylinder alignment.....which can be affected by the parts change. You should verify the alignment with a "field" range rod after the work is completed.

Remember too, the model 27 has a comparatively heavy cylinder assembly, so try to always use the proper technique when closing the cylinder, and when dry firing.

 

[GWW]

Thank you both gentlemen, I'll take your advice and leave it as is. My carry gun is a 1911, this 27 is just for punching holes in paper in tightest groups I can muster, these days not as much as when I use to shoot Bullseye matches. I bought a range rod and checked the alignment, she's good now. I look forward to reading the book, I love soaking up the knowledge. I'd rather read a shop manual then a best selling novel, one is entertaining and the other useful in life.

As a young lad I drove my parents nuts by taking things apart just to see how they worked, after I ruined the toaster Dad put an end to that but saved anything that was to be tossed for me to play with. I remember when the motor of Dad's old riding mower seized and Dad let me have at it. I tore it apart, filed down the burrs on the crankshaft and connecting rod with the only file I could find, a wood rasp. I made new gaskets from cereal boxes and got it running, knocked pretty good but it ran, Dad was impressed and so was I, I was 11 years old then.

Cheers gentlemen, I appreciate it greatly! A Happy Forth to you!

 

[RVRSMITH]

I'm in the process of fitting an oversize cylinder catch in a 27-3, I have a perfect fit to the cylinder and the window in the frame, it locks up very nicely, but during a pull of the trigger the ball drops below the window in the frame about .002. I'm not sure where to remove material to keep it from dropping below the window, the Recovery Surface or the Bevel as pointed out in the attached photo? Thank you in advance!

.002" thou is not horrible,however perfection is what us smiths seek! Stoning a slight 45 degree chamfer underneath the trigger nose will eliminate it dropping below the window, take very very little bit at a time! This will delay any additional drop while still keeping the timing.

 

[GWW]

Gentlemen, It's been a while but I just wanted to follow up and thank each of you for your advice and guidance. I had put the project aside for some time, yesterday I finally put the finishing touches on the cylinder catch and hand to ratchet fittings striving for perfection which I achieved. The lockup on each cylinder is now perfect, the hand just touches the ratchets with zero binding or drag, working on one ratchet at a time I inked them checking for contact then carefully, slowly removed just a layer of ink and rechecked until each cylinder is now perfect. The catch now drops nicely now and stays within the window of the frame, breaking the edge I put a slight polished bevel on the right side of the ball as the final touch. Checking the cylinder alignment with a range rod is also right on the money, in lockup there is zero play in the cylinder. A slow chock of the hammer gives three satisfying clicks on each cylinder. This lockup with zero play and solid timing is exactly what I was striving for but to be honest I wasn't sure I would be able to achieve this level of perfection, I expected the work to be a good improvement but I really didn't think it would turn out this well!

It was a very gratifying learning experience which I greatly enjoyed and I wouldn't have been able to achieve the wonderful end results without your help, I Thank You!

I've had this 27 for 18 years now and the poor lockup had always bugged me, other wise it was such a fine piece and it deserved to function to it's full ability, I can now fully enjoy it! I'm looking forward to getting to the range, hopefully soon, and check the groupings. I have a wide range of .357 and .38 reloads ready to go, just need to find a day without rain and without pain, I don't have that many good days where I can enjoy range time but I'll squeeze at least one in as soon as the stars align before the snow falls. I'll try to get some target photos and follow up when that day comes.

Thanks again, cheers!

 

[RMFnLA]

For just .002" I'd degrease the parts and do a good bit of dry-firing in front of the TV to see where it goes after some natural wearing-in.

 

[GWW]

For just .002" I'd degrease the parts and do a good bit of dry-firing in front of the TV to see where it goes after some natural wearing-in.

I have been dry firing with dummy rounds but with parts lubed, I intended to leave things on the tight side for break in, I can always go back in and dress things more but as you know, easy to remove metal, not so easy to put back. I'll take your advice, degrease and do some more dry firing.

I also expect I'll get some additional break in during the pressures of live firing, not as much as say a slide to frame fit on a semi auto but still additional break in during live firing, correct?

Thank You!

 

[RMFnLA]

I have been dry firing with dummy rounds but with parts lubed, I intended to leave things on the tight side for break in, I can always go back in and dress things more but as you know, easy to remove metal, not so easy to put back. I'll take your advice, degrease and do some more dry firing.

I also expect I'll get some additional break in during the pressures of live firing, not as much as say a slide to frame fit on a semi auto but still additional break in during live firing, correct?

Thank You!

Dry firing unlubed won't really remove metal, it will just allow the parts to "marry" a bit. I suspect you will end up with a perfect fit.

I don't think live firing will make any difference with those parts; there's no change in their dynamics with or without ammo.

 

[GWW]

Dry firing unlubed won't really remove metal, it will just allow the parts to "marry" a bit. I suspect you will end up with a perfect fit.

I don't think live firing will make any difference with those parts; there's no change in their dynamics with or without ammo.

Thank you. I've always tried to do as much as my own smithing as I can, knock on wood most of the time I've had good results, a few times I had to have my gun smith buddy bail me out but I try. I was a little intimidated with this 27 project once I found how precise the parts work in conjunction with each other and how little wiggle room you can have before you go too far, I'm more then pleased with the results, it's very satisfying to do it myself. What amazes me is how such a fine tuned and really delicate system with some of the relatively soft parts will hold up for such a long time! These older Smiths are really a pleasure to own and shoot, you can tell the people who built them took pride in their work, right down to the fine checkering along the top, amazing craftsmanship. There's just something about these revolvers I've always been drawn too, just wish I could afford more of them!

 

[RMFnLA]

It occurred to me that you don't actually have to dry-fire to break these parts in.

I would remove the hammer and mainspring as well as the cylinder and just work the trigger and cylinder lock assembly a whole bunch, again without lube.