Re: Barrel flutinz!
I don't think it'd be possible with a water jet. A sinker EDM could I guess if your a sicko who loves to make life extra complicated.
Understand that ANY machining operation using a cutter/insert to remove material does not "induce" stress. It relieves it. Seriously.
A simple example. Take a ball of rubber bands. Start snipping at it with scissors. Your removing stress by doing so. The caveat though is that you may not be removing it symmetrically or with a predictable outcome. Meaning no certainty that the ball remains spherical. You might end up with an egg instead.
Materials (most anything) behave in much the same manner.
If we throw a plate of steel in a vice and fly cut one side it's very possible that when we pop it out of the vice it'll bow up like a cat does when being petted. Did we create stress? No, we removed it from one side of the piece which caused a distortion due to the material "stress relieving".
Barrels, good ones anyway, are "normalized" as part of the manufacturing process. This is nothing more than an attempt to put the steel in a "dead" state so that things like temperature change, machining, etc. doesn't influence the material in the finished state. (Meaning the hole down the middle where the bullet passes)
A properly normalized barrel shouldn't take on the form of a banana due to fluting. Be that as it may, it's still probably a sound practice to machine conservatively and to use a quality cutter (sharp) with flood coolant to mitigate wild changes in temp. The intent being to avoid further stress relief that could possibly distort the hole down the middle.
For the record I am no expert on this. I've only fluted 4 barrels in my life. 3 of which were done yesterday. I have however made quite a bit of stuff in a machine shop and the principles are all the same. These were Rock Creek barrels which are cut rifled. Button barrels are supposedly a little more sensitive to fluting operations, but a number of other smiths do it day in/day out with no ill effects. I've avoided doing this kind of work in the past due to lack of proper fixturing, tooling, and the assumed risk. It's one thing to scrap a piece of AL or steel while making something. You cuss a little and then go make another one. The obscenities really fly when you take a $300+ dollar part that can take up to a year to get and ruin it due to a bad number in a program or setup goof.
One thing I do really like about the cutter geometry I'm using is that the flutes AREN'T razor blades. Few things in a gun shop will slice the piss out of your hand the way a fluted barrel will right after being spun polished. The cutter I chose has a chamfer on each side with a flat bottom. Similar to an Acme thread I guess. The chamfer takes the razor sharp edge away. Nothing earth shattering but kinda cool. -different. . .
The internet can be a wonderful tool. It can also a great source for disinformation.
Hope this helped.
C.
Good stuff - thanks!!
