I bought a Jenks Carbine several months ago and posted some photos of it and a nipple wrench I made in the Percussion Rifles section - https://www.muzzleloadingforum.com/threads/the-jenks-carbine-a-blast-from-the-distant-past.117571/
I became curious about finding a replacement nipple and assumed it was the same as those use on other U.S. muskets. U.S. musket cones are 5/16" x 24 TPI (threads per inch) and are 3/4" overall length. So I removed the Jenks cone and found that it is probably unique to the Jenks carbine/rifle. The cone is 9/32" x 22 TPI x .625" overall and here's a photo of the wrench and nipple -
I machined the threads on a 3/8" diameter rod and it wouldn't thread into the barrel, so I thought maybe the thread was 23 TPI and I made one & it wouldn't thread into the barrel. I messed around 3 more times threading the 3/8" rod but nothing would thread into the barrel. Here's a photo of the rod with 22 TPI & the Jenks cone -
They sure looked similar. I took a loupe and looked at the Jenks cone and the threads are standard 60 degree vee threads but instead of a vee point at the bottom of the thread there is a flat instead of a vee. So today I tried grinding a small tool to match the Jenks thread and I finally got the rod to thread into the barrel.
So here are a couple of photos machining the nipple:
I machined the 2 notches for the wrench, then I drilled the rod with a 1/16" drill through the length of the cone, then counter drilled with a 5/64" drill in the bottom 5/32" deep and here I have turned the nipple cone area -
Here I'm cutting the cone to rough length (the photo is blurry because the camera decided the lathe cross slide was more interesting) :
Here I'm enlarging the 1/16" hole to 5/64" on the front of the cone (I've seen drawings of cones the English used on their Enfield rifles and I know they used tapered holes - but I'm fresh out of tiny tapered drills.):
Finally a comparison photo of the cones:
I still have some minor filing to do on the notches and checking the overall length.
Tomorrow I'll test harden the threaded rod and then harden & temper the nipple.
Later, Mike
I became curious about finding a replacement nipple and assumed it was the same as those use on other U.S. muskets. U.S. musket cones are 5/16" x 24 TPI (threads per inch) and are 3/4" overall length. So I removed the Jenks cone and found that it is probably unique to the Jenks carbine/rifle. The cone is 9/32" x 22 TPI x .625" overall and here's a photo of the wrench and nipple -
I machined the threads on a 3/8" diameter rod and it wouldn't thread into the barrel, so I thought maybe the thread was 23 TPI and I made one & it wouldn't thread into the barrel. I messed around 3 more times threading the 3/8" rod but nothing would thread into the barrel. Here's a photo of the rod with 22 TPI & the Jenks cone -
They sure looked similar. I took a loupe and looked at the Jenks cone and the threads are standard 60 degree vee threads but instead of a vee point at the bottom of the thread there is a flat instead of a vee. So today I tried grinding a small tool to match the Jenks thread and I finally got the rod to thread into the barrel.
So here are a couple of photos machining the nipple:
I machined the 2 notches for the wrench, then I drilled the rod with a 1/16" drill through the length of the cone, then counter drilled with a 5/64" drill in the bottom 5/32" deep and here I have turned the nipple cone area -
Here I'm cutting the cone to rough length (the photo is blurry because the camera decided the lathe cross slide was more interesting) :
Here I'm enlarging the 1/16" hole to 5/64" on the front of the cone (I've seen drawings of cones the English used on their Enfield rifles and I know they used tapered holes - but I'm fresh out of tiny tapered drills.):
Finally a comparison photo of the cones:
I still have some minor filing to do on the notches and checking the overall length.
Tomorrow I'll test harden the threaded rod and then harden & temper the nipple.
Later, Mike
