A question on neck turning

[260AckImp]

I shoot a 260AI and have recently necked down some 308 brass to 260 ready for fireforming. Ive discovered that after necking down to 260 my loaded neck diameter is .296 to .297 and my chamber is a .298 neck. I like to have .004" clearance as a minimum and would even rather .005 to .006 of clearance.

My question is how much are you able turn off a neck in 1 pass? Would I be able to turn off the .002" in one pass or do you turn down in a couple of passes taking smaller cuts each time?

I have a Sinclair Deluxe 1500 neck turner coming in the mail.

 

[Bill Norris]

Yes you can turn .002 at one pass with no issues. Makes for a better quality job to make 2 passes at whatever you are planning to remove unless you are just doing a slight clean-up turn.

 

[Big Mc]

I shoot a 260AI and have recently necked down some 308 brass to 260 ready for fireforming. Ive discovered that after necking down to 260 my loaded neck diameter is .296 to .297 and my chamber is a .298 neck. I like to have .004" clearance as a minimum and would even rather .005 to .006 of clearance.

My question is how much are you able turn off a neck in 1 pass? Would I be able to turn off the .002" in one pass or do you turn down in a couple of passes taking smaller cuts each time?

I have a Sinclair Deluxe 1500 neck turner coming in the mail.

What Bill said. Tommy Mc

 

[762plinker]

yes two passes is better, a ruff cut to get close..say .0008/.0005 and then a final to target number

 

[260AckImp]

Yes you can turn .002 at one pass with no issues. Makes for a better quality job to make 2 passes at whatever you are planning to remove unless you are just doing a slight clean-up turn.

Thanks for the advice, ive got some old cases to practice on first before trying the Lap cases.

 

[Bill Norris]

Thanks for the advice, ive got some old cases to practice on first before trying the Lap cases.

Oh yes, always good to practice on old cases before putting the blade to the good stuff. Run the cutter up to and kiss the shoulders but I would not cut into the shoulder.

 

[FNSafari]

.oo2 is not much...just .001 a side. One pass is a piece of cake for that much imo. It takes a bit, unless you are lucky, to get the tool adjusted to do just what you want. Once you do at
002 just go for it.

 

[Bill Norris]

.oo2 is not much...just .001 a side. One pass is a piece of cake for that much imo. It takes a bit, unless you are lucky, to get the tool adjusted to do just what you want. Once you do at
002 just go for it.

I think he was wanting to take .002 per side according to his numbers in his first post.

 

[FNSafari]

I think he was wanting to take .002 per side according to his numbers in his first post.

If so Bill, I still think that is a one pass deal. imho. Tks

 

[Bill Norris]

If so Bill, I still think that is a one pass deal. imho. Tks

I agree, but it seems to me when I take it off in two steps the job comes out more evenly around the case circumference when measuring with a micrometer of course.

 

[LHSmith]

Maintain the tool and brass at a constant temperature. I place the tool on something cool in between passes- i.e. a cold wet cloth.

 

[Bill Norris]

Maintain the tool and brass at a constant temperature. I place the tool on something cool in between passes- i.e. a cold wet cloth.

Absolutely better not to run it hot. On another note Jack Neary says to expand one case just prior to turning it.

 

[Mark611]

This is why Sinclair/ Brownell's sells both the expander and turning mandrels just for this purpose!

 

[Straightshooter1]

Maintain the tool and brass at a constant temperature. I place the tool on something cool in between passes- i.e. a cold wet cloth.

Because my work bench is in my garage where there's no temperature controls, the hot Arizona summer can be a problem keeping things cool. I figure out to do this same thing, only instead of a cold wet cloth, I simply set my tool on top of an frozen jell pack after finishing a case, while loading up the next. It actually works quite well in keeping the temperature of the tool down and without having to wait for it to cool down in order to go on to the next case.

 

[JimPag]

If so Bill, I still think that is a one pass deal. imho. Tks

I agree Greg.

 

[Ray123]

I don't neck turn with hand tools...to get precision you should probably do a finish cut into the shoulder, so 2 passes, rough cut finish cut.
But I don't do it that way...
I use a precision lathe with collets and a piece of metal I just turned for zero runout. Grind a super sharp carbide OD tool with the correct angle and radius (leave the R smaller than the print) in the diamond grinder... then make a holder to hold the case OD for a 1" collet with the correct case taper and use a small carbide boring bar to bore the neck ID. So I can take a .010" cut or more with no effort...in very short time... big electric motor does all the work. With radical case forming ...even re cutting the extractor grooves and solid head ...like 308 to 6 mm ARC. When cases are in short supply, make your own...a 308 will make a lot of different cases...never out of brass...only have shotgun primers ...modify a few 308 cases.
All reloaders and shooters should own and be able to use machine tools....new school curriculum, forget the critical race theory crap and learn something useful, machine tool technology, apprenticeship, so without a manufacturing base you can make it yourself.
I could be a high-school instructor, "Welcome to my high-school class." ..."students,.. today we will be learning to build an accurate AR 15." "The accuracy of your project and the difficulty of your modifications, will determine your grade."
"Let's begin."

 

[Mark611]

You know I agree to some level that some people should learn to use tools like this some have no business touching them!!! I am a supervisor at a very large machine shop, that makes CV joints for automotive industry, NDI, IMO and I see this everyday most people can't even master a set of micrometers correctly, turning necks like your doing takes a lot of skill most people don't possess let alone having access to that kind of machinery or tooling, IMO if you know how to use a hand neck turning set up you can still achieve your goal, also my Wilson trimmer has tooling to do inside neck turning or reaming, it may not quite precise as a lathe set up with a boring bar, but it will get the job done if need be! also, the way your doing this is very time consuming even tho it's probably the most precise.

 

[ebb]

Set depth of cut to make finished diameter neck. Make a pass to remove most of the metal, it will not be smooth and have ridges in it make a second pass very slowly on feed rate and it should be very smooth (no ridges). No need to adjust depth and make a light cut them readjust to the final depth.

 

[260AckImp]

Set depth of cut to make finished diameter neck. Make a past to remove most of the metal, it will not be smooth and have ridges in it make a second pass very slowly on feed rate and it should be very smooth (no ridges). No need to adjust depth and make a light cut them readjust to the final depth.

On the first pass do you feed the case a bit faster so it doesnt remove the full amount of brass? And then on the second pass when you feed it slower it removes the full amount set on the neck turner?

I also forgot to ask what lube everyone uses on their mandrels? I only got Imperial Wax for the time being

 

[Bill Norris]

I feed both runs slowly. I use Lee "white stuff" and Imperial sizing wax.