neck wall thickness

[Bkluke]

how thin is to thin on the neck wall? just trying neck turning for the first time. not sure

 

[expiper]

HI Luke.....I had a .260 nk 6mm BR bak in the 70's and had to turn the necks to .0075 ....that doesnt sound like much thinner than .0085....but if you just bumped em into each other or handled them a lil rough...they would get a flat spot or ding on the neck....very delicate.....so that is too thin....and that was on a 6mm.......but you may be asking what is too much clearance..???? ....that is a good un....most folks say one half a thou per side or a total of one,.001") is very close ....I usually run .0025 to .003 total and have NO problems....with pressure or neck splits or wear etc. etc...so If you have a .340 nk ...a loaded neck at aroudn .337-338. would be great .....and a typical no turn nk on a 6mmBR is .271 or .272 so most of my un-turnd ctgs measure aprox .2685 ....just rite and NO TURNIN...that is why I went that route....but no matter what you gotta have clearance....so do the math....you will ruin a coupla brass rite off the bat....,,,at least I do...))) ....I use culls and old stuff layin around to get the cutter depth real close ...then go to work on the real thing.....Roger
I forgot ....if can ...make two cuts or passes....if your goin way down...like a .262 nk....take most off the first cut ...then shave the last lil bit off ...this method usually give more uniformity and less torn or damaged necks,,less torque required to do the work......lube the mandrel with le-clear or half stp and half synthetic motor oil....keep things smooth and simple....and of cours trim to length first because the spud on the turner stops at the case mouth....so if they are not all the same ...the ammount turned will vary....

 

[Bkluke]

thanks for the help roger