Neck Turning with RCBS Trim Pro Power - why not?

[HuntingBronco]

Why not? RCBS says NO. Have had Trim Pro-Power for years and can't see why not, so for $47, I figured I'd give it a try. Set stop to stop at shoulder. Loosen thumbscrews so it manual feeds... seems to work like a charm. I'll attach a photo and video (couldn't) Seems to be very consistent, coming out at .135" Anyone see anything bad going on here? I can attach different photos....

 

[Reelamin]

I'm in to see what comes out. I already have the tools. Never wanted to buy a separate neck turner. I absolutely don't see why it would be a problem. Only question is the smoothness of the cut. What do you mean loosen thumb screws so it manually feeds?

 

[HuntingBronco]

Cool. Maybe extra images will help. Rate of feed in and out seems to dictate how smooth - but that's likely true for all. Seems like it's just a lathe after all. The motor unit has three black thumb screws to lock it on the carriage. Normally, you set this and let the springs feed the cutter to cut the mouth for length and chamfer. I just loosened them, set the depth collar and manual feed. The 4 in my hand, two on left hit with Scotch Brite pad. Two on right not hit with pad.

 

[Orange Dust]

Cool. Maybe extra images will help. Rate of feed in and out seems to dictate how smooth - but that's likely true for all. Seems like it's just a lathe after all. The motor unit has three black thumb screws to lock it on the carriage. Normally, you set this and let the springs feed the cutter to cut the mouth for length and chamfer. I just loosened them, set the depth collar and manual feed. The 4 in my hand, two on left hit with Scotch Brite pad. Two on right not hit with pad.

Been doing the same thing with a Forster trimmer for years, many years. I would go a few thousands deeper into the shoulder though. You need a slight relief cut into it to prevent doughnuts and having to ream the inside of the necks. The neck turning adapter for a Forester trimmer does cut much cleaner and smoother.

 

[HuntingBronco]

The rcbs pilot inclues a reamer. Was wondering about how far to push into the neck junction. Cutter doesn't appear to be ground for it the way some tools are.

 

[Orange Dust]

doughnuts won't appear until the turned case has been fired and resized. May take a couple of firings to appear. If you get them you can remove them with the inside reamer. To avoid them, you have to turn the neck a little into the shoulder. this makes a relief cut giving the brass a place to flow to. It isn't much. Fingernail thickness about.

 

[Orange Dust]

Another thing. don't get carried away turning necks. If you are turning necks for a chamber designed for turned necks, turn to the correct clearance. BUT, if you are turning for a SAAMI chamber, watch out. Turn to clean up no more than 1/2 way around the neck. Just knock off the high side. Figure out what that is and make every case the same, but don't take any more off than absolutely necessary. do it right and you can enhance accuracy. Do it wrong and not only will accuracy go down, the cases are more or less ruined.

 

[HuntingBronco]

Hard to unturn! This is mostly junk brass. So good to learn on. Appreciate the wisdom passed along.

 

[HuntingBronco]

So this gave a skim cut on 50% of circumference. Thin side is about .0135. Cut side is about .016.

 

[HuntingBronco]

This about 95%. Thin spot still at .0135. Cut is now at .014. What should I be aiming for? Also note - i adjusted cut further into shoulder.

 

[HuntingBronco]

Not sure if this is a reason to turn or not, but this 264wm winchester brass neck thickness varies a lot, it seems. .0135 to .017 or .018 on a single case. Using ball mic to measure

 

[QuietTexan]

3 thou+ variance, the junk part of the brass description is accurate The last box of Lapua I cracked open, none of the ten cases I selected randomly to measure neck thickness on varied more than 0.0008", average was 0.0006".

This about 95%. Thin spot still at .0135. Cut is now at .014. What should I be aiming for? Also note - i adjusted cut further into shoulder.

You should basically start at this point with decent brass, then when you skim them down to between 50-75% of the neck cut you should be at a less than a half-thou variance. If you fully turn them down you should be at 0.0001".

This kind of turning begs the question though, what's your neck clearance, and what's "too thin" for your chamber? I wouldn't clean up anything past 80% unless it's tight necked and needs it.

 

[HuntingBronco]

I really appreciate everyone's comments and guidance. I am going to walk away from this feeling like, if I need to turn necks, I have a tool that is capable (maybe not perfect) - but a solution for $50 invested. Happy to now have a platform that let's me learn about neck turning.

It also sounds like I could have saved $50, as I don't have any custom chambers with tight necks.

 

[QuietTexan]

NO! No showing self-awareness and pulling back. Down the rabbit hole and through the looking glass with you!

Cleaning up necks can be very useful, but as much of variance as you were seeing IMO points to the rest of the case having similar tolerances. I think you could upgrade to a more uniform brass (not saying you don't already, just comparing to what you were using) and get more benefits than just uniform neck thickness.

I don't think there's a downside to skimming necks to 50% for any chamber, but when you start cutting the full neck and reducing thickness more that's when neck clearance comes into play.