First neck turning experience, start with GI brass?

[stubbicatt]

Heya guys. I haven't decided on a neck turning tool just yet, but wondered whether it would be a good idea to start my neck turning lessons on old GI brass? I would hate to screw up my Lapua cartridges.

Thanks.

Oh -- recommendations on the neck turner?

 

[savageshooter86]

YES. Or scrap range brass. Practice on them to get the feel and set it up close then fine tune it. That is what we did when did my 300 pieces of virgin 308 win Lapua brass

 

[Martin52]

I think that is a great way to start if you have not neck turned before. It is way too easy to stuff up your good brass, use discarded range brass until you get it right.
As to tools, there are a few good options. Personally, I use a K&M turner with matching expander mandrel that screws into my press.
Before practicing, go through all the case prep. steps, there are plenty of articles on the forum if you do a search, basically, deprime, clean, FLS (use a non bushing die before turning), trim to length then turn the necks.
Accurate measuring of the turned neck thickness will require a ball or tube micrometer. You can get close though by attaching a dial indicator to some neck turners eg the K&M but clean the case and the mandrel of all lube before trying to measure.
That's just a few basic comments, try the "search" and you'll find plenty of info to guide you.

Martin

 

[nosualc]

As long as it's clean, cheaper (whatever the source) brass is a great to learn turning. You will destroy a few cases along the way getting a feel for it and getting things adjusted, might as well do it inexpensively.

I recommend the pumpkin turners. They're pricey, but once you get the hang of em they produce really nice results.

-nosualc

 

[jonbearman]

It appears to me the pma model a is the way to goI believe but it should have a click micrometer if I have the right model.Go to pma and take a loo at what they offer and get the carbide turning mandrels if you can afford to buy the right one for your application.

 

[thefitter]

It appears to me the pma model a is the way to goI believe but it should have a click micrometer if I have the right model.Go to pma and take a loo at what they offer and get the carbide turning mandrels if you can afford to buy the right one for your application.

+1

I learned on a pumpkin which is a great tool, but if I had to recommend one turner especially for a beginner it would be the PMA. Very easy to set up!

 

[bouddha]

PMA cured my neck turning blues!

 

[Three44s]

I don't have the good tools that other members here have ........... I use a Forester case trimmer set up .......

My suggestion is to go easy. Watch out that you don't harm the shoulder of the case .... running too far down the neck ........

...... and don't try to take all the cut at first ....... even if you leave a very slight low spot now and then.

The reason is that it's all too easy to thin your necks more than you should at first. The downside is you'll unnecessarily lose neck tension.

You can always cut more off ....... but it's real hard to grow some back on .... and yes, don't touch your Lapua brass for a while.

Three 44s

 

[stubbicatt]

Lemme see if I get this right.

Step 1: Full length resize case without any expander ball. Decap.

Step 2: Trim case

Step 3: Use mandrel to expand case neck.

Step 4: Measure with tube micrometer the case neck

Step 5: Set up trimmer per instructions

Step 6: Make light trim.

Step 7: Adjust to cut a little deeper. Repeat as necessary.

Is there a thickness that is considered minimum allowable case neck thickness? Like maybe .01" or something?

Tnanks guys so very much.

 

[savageshooter86]

For a 308 win? If so Lapua cases will probably be close to 0.015 neck wall thickness average. I recently took mine down to 0.014 thickness and cleaned up 100% of the necks. They turned out really nice. Out of 300 cases I had maybe 5 that had low spots left on part of the neck

 

[jo191145]

Lemme see if I get this right.

Step 1: Full length resize case without any expander ball. Decap.

Step 2: Trim case

Step 3: Use mandrel to expand case neck.

Step 4: Measure with tube micrometer the case neck

Step 5: Set up trimmer per instructions

Step 6: Make light trim.

Step 7: Adjust to cut a little deeper. Repeat as necessary.

Is there a thickness that is considered minimum allowable case neck thickness? Like maybe .01" or something?

Tnanks guys so very much.

Just remember, (assuming non fitted custom chamber) the more you take off the more your brass will need to move upon firing and resizing. The more it moves the faster it will harden causing accuracy issues.
If you have a largish factory chamber 9 out of 10 times your better off in the long run not turning brass. Get brass that doesn't show huge variations in thickness and your done.

FWIW the K&M turner (which I use) has a problem with heat build up. The Aluminum body can throw off cutting depths very quickly by just body heat. I do five pieces at a time run by drill then let it cool to room temperature about five minutes before picking it up again.

 

[Martin52]

[/quote]

FWIW the K&M turner (which I use) has a problem with heat build up. The Aluminum body can throw off cutting depths very quickly by just body heat. I do five pieces at a time run by drill then let it cool to room temperature about five minutes before picking it up again.
[/quote]


Anyone know if the heat build up is a problem with the PMA N/T ? I have the K&M.
Martin

 

[jlow]

The K&M neck turner body which hold the pilots (mandrel) are aluminum but the pilot themselves which is the only part outside of the cutter is the only place your brass has direct contact with is steel not aluminum.

You should not build up heat from cutting unless you do not lubricate the pilot and case neck well with Imperial and/or you are taking too big a cut and at too fast a rate of cut both of which will not only build up heat but give you erratic cutting depths which should be avoided.

All these problems I think would be true for all neck turners if you do not take the above precautions.

 

[jo191145]

The K&M neck turner body which hold the pilots (mandrel) are aluminum but the pilot themselves which is the only part outside of the cutter is the only place your brass has direct contact with is steel not aluminum.

You should not build up heat from cutting unless you do not lubricate the pilot and case neck well with Imperial and/or you are taking too big a cut and at too fast a rate of cut both of which will not only build up heat but give you erratic cutting depths which should be avoided.

All these problems I think would be true for all neck turners if you do not take the above precautions.

I'm not referring to heat from cutting friction. Its simply body heat in comparison to ambient temperature that can create variable cutting depths. K&M sells an ergonomic rubber boot to cover the Cutter body. Me thinks its more of an insulator than ergo thing but that's just a guess.
The first time I used my K&M I made the mistake of doing it outside on the patio. The job began in the shade but as the sun rose I got full sun. I thought my new turner was a piece of junk. I then remembered reading a post about such things on BR Central.
The K&M does a fine job if you can keep that Aluminum body a fairly consistent temperature and are aware of that fact.
I usually turn five pieces then take a five minute break. Works well for me and I have no problem with taking breaks LOL.

 

[jlow]

Thanks! I understand where you are coming from now. The pilot and cutter holder is indeed small and I can see how you can transfer body heat to it. Have not seen the “rubber boot”, but they do sell this “Ego Holder” which is a much bigger hunk of aluminum and would only be connected to the pilot/cutter holder via a set screw and it allows you to hold it much easier – highly recommended especially if you are going to turn with a hand drill as it gives you a much better grip and prevents any binding from torturing your hand.

http://www.kmshooting.com/catalog/neck-turner-tools/ergo_holder.html

But from my personal experience, the biggest heat and the resultant expansion threat comes not from your body but the turning itself. Turning a piece of brass fast and deep will heat it up to temps that are almost too hot to hold. A good way to test how well you are doing is to turn the brass, slide it off the pilot and put the neck of the brass up against the skin of your face. If it feels cool – you are golden. If it feels warm and especially hot, you are turning too fast and you will have irregularities in thickness.

 

[GPat]

Every neck turner will warm up a bit when used, even with carbide and good lubricant, don't get me wrong, carbide and good lube will make your neck turning a LOT better, with less heat, but everything in the system is going to get warm from use. To avoid excessive friction and therefore heat, make sure the case necks fit the turning mandrel well, if that means running the cases over the expander twice or polishing a mandrel, do it. Use a good lubricant when neck turning and if you feel the tool heating up don't be afraid to douse it in water or rubbing alcohol. Let it cool off a bit than get back to it.

As far as the OP about G.I. or range brass. I wouldn't use it simply for the fact of the extra work you'll put into getting it cleaned and ready and that the metallurgy is likely very different from what you'll actually be using. What I do and what we recommend is that for every new set up for neck turning a new cartridge, use culled brass. That is the heaviest or lightest ones or the ones with big dings. Use those to set up the tool. You won't find the big dinged ones in your box of Lapua, but you'll definitely find a few that weigh light or heavy.

Neck turning isn't rocket science, when you're new to it, it can be scary at first. You'll ruin a couple of cases, MAYBE, but set the tool up to cut them thick, then take the rest off in a second pass. That first pass will ever so slightly change the fit on the mandrel so be mindful of adjusting it for the second pass, but that's not a big deal either.

Most importantly (especially if you're uncomfortable with doing this new case prep step) Watch some videos not only on setting the tool up, but mostly how to actually do the turning. Pay close attention to the feed rate and RPM. You'll get better results if you go slowly onto and off of the mandrel, don't just cram it on there. I've watched guys neck turn like that and I cringe.

Pat

 

[jlow]

Warm is a relative term and so always up for debate, but from a practical standpoint, temperature elevation is directly proportional to how deep a cut is made and how fast it is done. So with this in mind, one can see that it is entirely possible to do cuts that do not significantly heat up the brass i.e. slow and shallow cuts. It can be done, I do it all the time.

 

[stubbicatt]

A good way to test how well you are doing is to turn the brass, slide it off the pilot and put the neck of the brass up against the skin of your face. If it feels cool – you are golden. If it feels warm and especially hot, you are turning too fast and you will have irregularities in thickness.

I can imagine a bunch of guys at the benchrest match with several "cigarette burn scars" on their faces from this method of testing... LOL. This is how you tell a long time competitor... Nonetheless, the advice as I understand it is, if the brass at the neck is too hot to touch, you are either going too fast or cutting too much at a time. Thanks Jlow.

Thanks to all. I really appreciate you guys sharing your wisdom and experience with me on this subject. I'll approach it slowly and hopefully all will turn out well. The goal is to just uniform the necks, and to do this, it is best to go slowly.

 

[jlow]

Those are our “dueling scars”! LOL!

But seriously, the brass is done best when it feels cold after turning and not even warm. If you can do that, your neck thickness consistency around the neck using a three point measure will vary around 0.0002”. If it feels hot, you are way over the edge…

 

[savageshooter86]

interesting to know. My brass felt fairly hot when I was doing mine. I was using the PMA tool and their case holder chucked in a variable speed drill at low speed and didn't force the case onto the mandrel, just let it do it's own thing. Has me thinking now... :-\