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Posted: 12/20/2015 12:21:58 AM EDT
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I am waiting on my first stamp and planning my next 2, one will be a 762 and one will be a 22 lr. I have a good lathe and a mini-mill and am learning how to use them
I have some good books and my brother has some experience running them. My question is on a 22 lr can what would be the optimal wall thickness for cutting threads while still maintaining the strength needed? I would like to practice threading so when I finally get permission to make them I don't have any mistakes on my tube I will be using. Thanks KC |
| I assume you are talking about threading the tube. Your answer depends entirely on what threads you choose to use. There is no standard tube thread diameter or pitch to use. In general, finer threads are shallower and can be cut safely into a thinner wall, but that is a major generalization. If you don't understand that basic tenet of machining, I would seriously consider taking some classes before you attempt to make a silencer. You risk injury to yourself, or at the minimum accidentally fucking up a sizeable investment. |
| Im not really sure what you mean by the basic tenets of machining, I am pretty mechanically inclined and have been practicing turning down scraps it does not appear to be rocket science. For my first can i am using a SD tube that is already made and am planing on turning the baffles when my stamp comes in. My question was more pertaining to cutting the threads and if there was a sweet spot for the wall thickness, i am not concerned about losing a sizable investment because i am planning on knowing how to cut threads before begin making my own suppressor tube i just needed a starting point, as for injuring myself im not an idiot before i screw anything on the barrel of any of my firearms i will make sure it will be safe. Thanks for the help though |
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For a 22 LR 0.035 inch seamless SS tubing is plenty strong. The problem is having enough meat on the ends for threading for the caps and still have sufficient wall thickness. Smallest thread I would use is 28 TPI. I prefer 26 - 24 TPI since these are easier to cut and easier to thread together.
To calculate thread depth: Depth = P x 0.649 P (pitch) = 1/TPI For 28 TPI: P = 1/28 = 0.0357 D = 0.0357 x 0.649 = 0.023 inch For 24 TPI depth = 0.027 inch To have sufficient wall thickness of 0.035in with 28 TPI you would need 0.035 + 0.023 = 0.058 inch walled tubing. For 24 TPI you would need 0.062 wall. The closest commercial tubing is 0.065 wall. Simple answer is use 0.065 wall tubing and thread with 24 TPI. This will result in a heavier than needed wall thickness for the none threaded portion of the tube. If you want to reduce the weight you can turn down the exterior of the tube between the threaded ends on a lathe. I suggest you first cut & thread the endcaps to size. These are easier to thread and measure correct thread depth than internal threads. You then use your caps as a thread gauge when you cut the internal threads on the tube. Go slow cutting the last couple of thousandths and check for a good fit with the caps. If you have never done internal thread cutting in SS you will need to practice, it's not hard to do but it takes some skill. Good luck |
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Quoted:
For a 22 LR 0.035 inch seamless SS tubing is plenty strong. The problem is having enough meat on the ends for threading for the caps and still have sufficient wall thickness. Smallest thread I would use is 28 TPI. I prefer 26 - 24 TPI since these are easier to cut and easier to thread together. To calculate thread depth: Depth = P x 0.649 P (pitch) = 1/TPI For 28 TPI: P = 1/28 = 0.0357 D = 0.0357 x 0.649 = 0.023 inch For 24 TPI depth = 0.027 inch To have sufficient wall thickness of 0.035in with 28 TPI you would need 0.035 + 0.023 = 0.058 inch walled tubing. For 24 TPI you would need 0.062 wall. The closest commercial tubing is 0.065 wall. Simple answer is use 0.065 wall tubing and thread with 24 TPI. This will result in a heavier than needed wall thickness for the none threaded portion of the tube. If you want to reduce the weight you can turn down the exterior of the tube between the threaded ends on a lathe. I suggest you first cut & thread the endcaps to size. These are easier to thread and measure correct thread depth than internal threads. You then use your caps as a thread gauge when you cut the internal threads on the tube. Go slow cutting the last couple of thousandths and check for a good fit with the caps. If you have never done internal thread cutting in SS you will need to practice, it's not hard to do but it takes some skill. Good luck Great, this is exactly what I need. Thank you, KC |
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