Nipples and shoulders

Flint · June 12, 2009, 09:44:47 PM

Rolling Thunder, as Pettifogger said, #12 and 1/4 inch are quite different. 1/4 inch diameter is .250 inches. #12 is .216 inch.

To get the diameter of a numbered screw, for example, multiply the screw number by .013 then add .060. That makes a # 6 screw 6 X .013=.078, + .060=.138. #12 comes out to .216.

A 6mm thread diameter is .236, pitch .75 is 33.86/inch, so it's close to #14-34, if there were such a thing. MM/25.4= inches.

Mako, the #10s were pressed on with a push stick. They stayed on after the first loads were fired. Apparently the caps want a dirty nipple to stick to. I didn't fire caps to clear the nipples, as I had loaded the night before and blew the chambers and nipples out with an air compressor. I hate to waste caps, but perhaps the "clean" nipple is a disadvantage.

I loaded 8 cylinders and didn't want to fire 48 caps to clear them all.....

This is more information than anyone asked for isn't it? Flint

Mako · June 12, 2009, 11:18:05 PM

Quote from: Flint on June 12, 2009, 09:44:47 PM

Mako, the #10s were pressed on with a push stick. They stayed on after the first loads were fired. Apparently the caps want a dirty nipple to stick to. I didn't fire caps to clear the nipples, as I had loaded the night before and blew the chambers and nipples out with an air compressor. I hate to waste caps, but perhaps the "clean" nipple is a disadvantage.

I loaded 8 cylinders and didn't want to fire 48 caps to clear them all.....

This is more information than anyone asked for isn't it? Flint

Flint,
It's good info, not too much at all.

I would use #11s because they do seat more easily, but I have 2 Cash Cappers (both are in the gun cart already for tomorrow) and both of them have problems with a few of the shorter #11s getting turned sideways every time I use them. OK for practice sessions but a pain at the loading table when other people are waiting their turn to load. It seems Ted designed it for the taller cap knowing both would "fit." The caps are almost exactly 1/32" different in height (.175 and .144), I guess I need to modify one sometime by adding a spacer to the inside of the lid. I was going to shorten the other side to make it the way a #11 capper really should be made, but that is a bunch of work including redoing the hinge. I guess I'm feeling a bit lazy since I have #10s right now. The #10s work perfectly, I can go an entire match without having to rotate or pull a turned cap at the spring lips. I have a couple of straightline cappers from different manufacturers that don't seem to care which size are put in, but I keep the Cash Capper in my cap pouch and it holds enough for a match.

It also seems that #11s have gotten to be more common around here, or maybe it's just what I am looking for always seems to be the one in short supply. Any more I just buy 10 or 20 tins of whatever they seem to have in stock. Last time I stopped by a Cabelas they only had 11s and I tried to buy the entire racks worth. The guys in the loading area told me they were limiting us to 5 tins. I sent a friend the next day and he bought the 27 or so they had left and not a word was said. I guess he just took his up to the cashier. So in today's market it would seem prudent to have a capper for each size.

I wish Powder Inc. would carry primers then I'd just order everything from them. I got in on a cap buy maybe three years ago, but there aren't enough guys shooting C&B at my clubs to get an order together very often. I'm not picky any more, I buy them where ever and whenever I see them, I just hate paying 5 cents per cap.

I'm like you, I hate snapping caps, in fact I hit my nipples with carburetor cleaner just a couple of hours ago. Then blew them and the chambers out with compressed air, never had a problem yet. I leave them stored during the week with ballistol in them and degrease just the nipples and chambers with a can of cleaner and a spray straw to keep it off of everything else the night before.

Regards,
Mako
P.S. I'll PM you back about the sights, I might have you do one the other pairs.

RollingThunder · June 13, 2009, 07:12:52 PM

Well, I went on a run today, armed with the information I received here, I decided to hit a few gunshops and see what I could come up with. Well, only one gunshop in the area had anyone willing to help me. Apparently if you're not needing service on a high-end AR of some form or another, no one can bother with you.

The best "guess" I got was from the place I purchased the gun. They said to try 6x1mm nipples. This was after they recommended I use the 1/4 x 28 nipples, which Flint so kindly did the math for me here. When I explained that, upon visual inspection, those nipples were obviously longer that these. The gentleman on the other side of the counter explained that it wouldn't damage my hammer in the slightest if it's case hardened. I was more concerned about the nipple being mushroomed from the hammer, and needing replaced, much less the obvious difference in the threads.

So, seeing as I struck out at the hardware store as Mako said I likely would, and struck out at the gun stores (I even brought the cylinder in, and removed a nipple so they could see it -- ouch that hurt!

) I guess I'm just gonna take a WAG and contact the Possibles Shop and hope I get a lucky guess. I'll start with the 12-28s and see how it works.

Wish me luck!

Gun Butcher · June 13, 2009, 08:08:51 PM

RT, just a thought before you wing it . Is there a machine shop anywhere close to you. If there is I would think you might be able to get a machinist to 'mic' the threads or use a thread gauge to tell you what they are.

Mako · June 13, 2009, 11:21:03 PM

RT!!!!
Don't listen to any of those guys in the gun store! 12-28 doesn't refer to the length at all. It is the thread diameter and the pitch. The diameter is Ø.2150 Max and Ø.2085 Min. Flint gave you an excellent formula to allow you to calculate the diameter of unified screw threads. The 28 tells you how many threads per inch there would be. In no case does it tell you anything about the overall length. This isn't like a cartridge designation like the 9X19 or the 5.56X45 those do have a length component. This just describes the thread form, nothing else.

And the other part is rubbish as well. A correctly fit hammer should not hit the nipple. That is assuming the nipples are all at the correct height. If you have an interference fit you will mushroom the nipple. There are a couple schools of thought on hammer engagement/clearance. I'll tell you what I like.
Set the nipple height, or set the hammer face so it will just touch the empty nipples with the cylinder pushed to the rear if you push the cylinder forward to take up the cylinder gap a clearance will just show at the hammer nipple interface. A way to check is to strip the revolver and put only the hammer in the frame without a hand. Set the cylinder on the arbor pin and hold it vertically rotate the cylinder to each nipple and push the hammer forward while observing the cylinder it should just begin to be pushed up.

This way the hammer will never peen your nipples and a fully seated cap always sits about .039-045" higher than the face of the nipple.

The alternative is to do the same thing but with the barrel on and the cylinder pushed against the rear of the barrel. The hammer should just touch the nipples when the cylinder is at the furthest excursion forward. The problem with this is that the hammer will hit the nipple if dropped on a bare one most of the time. If I was using them for self defense I might have them set this way to maximize cap strike no matter the cylinder position. But for sport and as much as we shoot them I would rather them not hit hammer to nipple. That creates it's own problems, the caps sometimes seat short and you get soft hits and misfires.

When you get your new nipples take your pistols apart and try the first method and tell us what you observe. You may have to use pieces of very thin paper to act as feeler gages to see if you are touching.

You could try what Gun Butcher offered, but those guys at a general machine shop haven't ever seen a 12-28 thread before. They might have an inch pitch gage they could use, 28 TPI isn't uncommon, then just mic the diameter for you. But if they just try a quick thread gage plate there won't be a gage spot for it or for a 6X.75 either. 0.75mm isn't a common pitch for metric threads. If they are smart and actually listen to you they can figure it out.

The best of luck,
Mako

Pettifogger · June 14, 2009, 01:09:00 PM

This whole post has been about nipples and "shoulders." What the heck is a shoulder?

Mako · June 14, 2009, 01:35:56 PM

Quote from: Pettifogger on June 14, 2009, 01:09:00 PM
This whole post has been about nipples and "shoulders." What the heck is a shoulder?

Shoulders are usually above the nipples, unless of course they are bending over...

Mako · June 14, 2009, 01:38:51 PM

Pettifogger,
Seriously now, I took it to mean the area where the wrench engages.

I hope you smiled...

~Mako

RollingThunder · June 14, 2009, 02:45:51 PM

The shoulder on the nipple is the thinner part that has been machined away for the fingers of the nipple wrench to slot over, so that the slot engages the unmachined part to turn it. It covers the thread, and in this case, is not hard enough for any extra jostling the pistol produces through recoil to not be damaged. I gathered this from an old post by Cuts Crooked on fine-tuning cap fit on a nipple. Mentioned putting a nipple in a vice (ouch!) to contour it for a better cap fit, but that you should be careful or you may break off the shoulder if you put it in the vice incorrectly.

Best explanation I could do anyway.

Unfortunately, there are no machine shops around here that I would trust with much. I had one build a crazy wheel for my rough-cut mower last year, and then had to rebuild it myself because they forgot the bearings in the wheel (yay, fun!). Welds were decently strong, but looked like crap. They weren't real apologetic about it either. I just don't have much luck with folks standing behind their work.

I went ahead and ordered a set of 12-28s from The Possible Shop. If those don't fit, I'll send them back and order the 6x.75s.

If that don't work, I'm buying a whole new gun!

I'll be checking the hammer to nipple clearance as you described as soon as they arrive, Mako. Should be a really enlightening experiment. Do I back the hammer away, or do I file the nipple tops down?

On a serious note, I did take the wife out and shoot today. Shot on the un-broken nipples. She shoots really well, but prefers double action. Then we reloaded and I got to shoot, and it was really funny. She was sorta surprised that I could hit essentially the same spot on each shot. I rang the T-Post backing the target with each shot, in a one-inch spot. I told her it was flat-out luck. LOL. Which it was. I couldn't repeat that if I wanted to.

All the same, it never hurts to impress the War Department every now and again. Makes ya feel young.

Pettifogger · June 14, 2009, 04:45:03 PM

DO NOT file the nipple tops down. You will never get them square or equal length. If you need to adjust anything, adjust the hammer.

Mako · June 14, 2009, 10:27:58 PM

Quote from: Pettifogger on June 14, 2009, 04:45:03 PM
DO NOT file the nipple tops down. You will never get them square or equal length. If you need to adjust anything, adjust the hammer.

Listen to him RT he's absolutely correct. Not only that but you will mess up the taper fit for the caps. After you install the tubes you need to check just to make sure they are all the same height. If you have a caliper measure the distance from the back end of the cone to the front of the cylinder, they should be ± .002" to each other.

If you're going to be doing anything to the face of the hammer you might as well have the safety pin notch welded up. This will help stop caps that get pulled off if they extrude or rupture into that feature. Those safety pins are of little use to CAS shooters because you're only allowed to load five.

Regards,
Mako

Noz · June 15, 2009, 09:56:11 AM

Quote from: Mako on June 14, 2009, 10:27:58 PM

If you're going to be doing anything to the face of the hammer you might as well have the safety pin notch welded up.

Regards,
Mako

Mako, a 4 month or so fix for the safety pin notch is to buff it out well with a wire brush and fill it with JB Weld or a similar material. Not a permanent fix but lasts for a good while.

Mako · June 15, 2009, 01:01:35 PM

Quote from: Noz on June 15, 2009, 09:56:11 AM
Mako, a 4 month or so fix for the safety pin notch is to buff it out well with a wire brush and fill it with JB Weld or a similar material. Not a permanent fix but lasts for a good while.

Noz,
That's very true, in some cases it wall last for years

. I was just giving him list of things that he might want to do if he had to remachine the face of the hammer. He said he had people with welding skills llocally. If he was going to go to the trouble of remachining or filing the hammer face he might as well get the most out of it.

JB Weld works very well, like you said it just has to be super clean.

~Mako

P.S. For RT's sake I hope he just has to install the Treso tubes without modification.

RollingThunder · June 15, 2009, 02:56:15 PM

Quote from: Mako on June 15, 2009, 01:01:35 PM
P.S. For RT's sake I hope he just has to install the Treso nipples without modification.

For the sake of this poor gun, I hope you're right!

RollingThunder · June 20, 2009, 06:53:54 AM

I got the Treso nipples yesterday in 12-28, and installed them last night. The first one went in nice and smooth, with only a wee bit of resistance. I think the threads are sharper on the Treso nipples than they were on my OEM nipples. I thought perhaps I was gonna have a fitting issue after the first one though, as they seemed to have more resistance going in, and it sort of felt like they were rethreading, but as it turned out once it got the nipple into the cylinder, they went in smooth as butter.

And with the brass frame, they look really smart too!

So, they look good, and they fit snug and happy. Next item up for business is to measure for fitment as Mako described.

As for the safety pin notch, to which part are you referring? Is that the notch on the cylinder where the hammer rests between the chambers of the cylinder?