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Posted: 3/20/2005 5:15:06 PM EDT
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i got a 16" heavy barrel i want to flute it on my mill ! does any one know what sixe ball end mill and the depth for 4 flutes on the barrel ..and also how far to stay away from the breach end thanks for any help ' ' |
| I don't know about actual gunsmithing procedures, but I do run a mill and lathe, and it seems to me that a rifle barrel would be hardened so that it would be prohibitive to mill without first annealing the metal, then re-tempering it. I tried to mill and turn some parts from a car transmission that were hardened, and they chewed up even carbide tooling, unless you have some replaceable insert ball end mills, I wouldn't try it. I think if you did have to anneal and re-temper the barrel, plus, add in the cost of tooling wear and tear, it would be very cost prohibitive and you might as well buy a fluted barrel. Just my opinion, like I said, I'm not that familiar with just how hard barrels are baked to. I will add that you should be very careful if you do not anneal it, and just have your machine "muscle through it" with something like that, you could cause stress cracks to form and through the explosive firing process, they could get worse and cause barrel failure. |
| Heck, if barrels were that hard you couldn't touch them with a hacksaw, and guys cut them off regularly.!! A HS ball mill should cut flutes just fine, don't try to do it all in one pass!!. Biggest problem you will have is clamping/supporting the barrel evenly. End the flutes 2 inches from the muzzle to prevent any distortion, distance from the breech would probably be controlled by the barrel contour, you dont want to be fluting on a shoulder. Flute width (size of the tool) is a matter of individual preference, try a piece of round stock to see what you like (3/32 ball X 1/8 deep, depending on your barrel diameter). |
Barrels are not that hard at all and a 4 flute carbide endmill will work just fine. Id start with a half inch endmill and cut in .050 depth increments until satisfied. Mill from muzzle end all the way up till your about an inch or so away from where the barrel starts to heavily taper around the chamber. Dont forget to lock Y axis unless your on a prototrac mill using manual feed. Post pics when done 
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| the rockwell hardness of a barrel is typically around 28-32. if it were so hard you couldn't mill it then it would go kaboom when you shot it. as steel get harder it also becomes less ductile and more brittle. ductility is a good thing for a barrel as firing a shot is a high stress ordeal. the ductility allows the barrel to expand on an ever so minute basis and then return to its original dimesions with no ill effect. when a kaboom happens and the barrel splits the pressure was high enough to expand the barrel beyond the acceptable stretch. |
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