Nipple wrench?

[Marplot]

"There’s a good chance they would be a standard 1/4-28 nipple. No way of knowing for sure just yet. I have a J.D. Dougall double built in Glasgow, and it takes standard 1/4-28’s.

Ratcheting Nipple Wrench | TDC - Cash Mfg​

Easy to use ratcheting nipple wrench! Heavy duty *American made* ratchet with custom made ratchet head made with hardened steel that fits #11 nipples on rifles, musket nipples or pistol nipples. Tapered fit, standard 1/4" hex, interchangeable heads. Don't be afraid to push hard on the head to...

www.tdcmfg.com
Use the drop-down to select which combination or single attachment you’d like."

I am getting close. I see the attachments, "Pistol, Rifle, Musket" but don't see the 1/4-28?

 

[flconch53]

"There’s a good chance they would be a standard 1/4-28 nipple. No way of knowing for sure just yet. I have a J.D. Dougall double built in Glasgow, and it takes standard 1/4-28’s.

Ratcheting Nipple Wrench | TDC - Cash Mfg​

Easy to use ratcheting nipple wrench! Heavy duty *American made* ratchet with custom made ratchet head made with hardened steel that fits #11 nipples on rifles, musket nipples or pistol nipples. Tapered fit, standard 1/4" hex, interchangeable heads. Don't be afraid to push hard on the head to...

www.tdcmfg.com
Use the drop-down to select which combination or single attachment you’d like."

I am getting close. I see the attachments, "Pistol, Rifle, Musket" but don't see the 1/4-28?

The 2 different standards for thd measurement are metric and English. They certainly weren't using metric when that shotgun was made. They would more than likely be 1/4 28

 

[Keyhole]

I’ve had some luck in using small ignition wrenches to break loose a stubborn nipple

 

[BoomStick]

I am getting close. I see the attachments, "Pistol, Rifle, Musket" but don't see the 1/4-28?

Likely the rifle or musket fitting. If you get one of each you'll have a ready tool in your box for either common type of percussion nipple available.

All the advice about soaking in a penetrating oil, soaking some more and working with taps on the wrench has worked on stuck nipples for me.

 

[bpd303]

I make my own nipple sockets, 1/4 in breaker bar and sockets cut to fit snugly with a Dremel cut off wheel.

 

[Dusty_Traveler]

but don't see the 1/4-28?

1/4-28 refers to the thread size of the actual nipple itself. You will not know this measurement until you remove the nipples from your shotgun and measure them.

 

[Old Hawkeye]

I have some antique percussion shotguns and have damaged or badly plugged nipples. I see a lot of nipple wrenches for sale on Amazon. Some are for #11 or #12. Not sure what size I have on my guns. Is there a universal wrench?

Based on your questions & posts it appears you are new to the ML world & don't have a complete understanding of the various nipple types & sizes nor the appropriate tools & experience to remove the nipple in your picture. That nipple would not be a good choice for a "first time" attempt, as it appears to be very old & corroded in. I recommend you have a gunsmith familiar with this type work remove it, confirm the thread size & insure the threads are still within specs & safe to shoot. Best of luck!

 

[Dusty_Traveler]

@Marplot, how handy are you? Have you any experience working on small or delicate mechanical pieces? If you possess 'the feel' then you should be good to do your own work. I cannot describe 'the feel' any other way other than knowing when to stop applying force before something breaks.

@Old Hawkeye, if his gunsmith situation is anything like mine, there isn't one in a 300 mile radius that he would let touch his gun with a wet noodle. I can't recommend any of the smiths, even muzzleloader smiths, I have taken guns to.

 

[Pete G]

The 2 different standards for thd measurement are metric and English. They certainly weren't using metric when that shotgun was made. They would more than likely be 1/4 28

Don’t forget Whitworth threads.

 

[Johnny Tremain]

What's a "racket"?

Look up US government, its a racket.
what the "H" makes all the difference the world.