Scratches/grooves INSIDE neck after neck turning

[FrenchPewPiou]

Hi,

First time neck turner here. I'm using the K&M Neck Turning tool with 6.5 Creedmoor Lapua cases (LR primers).

I started with a big mistake: didn't lube enough and a ring of brass formed on the pilot (see on the picture below):

This caused deep scratches/grooves to form INSIDE the necks of the cases (I did 50 before noticing it...). On the video below you can see and hear the scratches:



I put the pilot in copper remover for a few hours and the golden ring completely disappeared.

I thought I fixed the issue for good, but now, even when using lots of lube (Redding Imperial Sizing Die Wax), there are light scratches (this time not deep, you can't/can barely feel them) but still, there are scratches...

Is this "normal" or should the inside of the neck be 100% free of any scratches? Did you ever experience this issue? What lube do you use to turn necks?

 

[John Glidewell]

polish it

 

[FrenchPewPiou]

polish it

What would you use (to also avoid polishing it too much)?

 

[John Glidewell]

either use a Dremel with buffer and a good polish or chuck the pilot on a drill and use a cloth with polish on it. You will see it smooth out. Might have to do it a few times. Just watch the pilot and brass as you go, if it starts leaving marks, polish it again. I do this with mandrels too.

Adding: also make sure you chamfer the case mouth. I typically run brass on a 3 way cutter to make sure they are all trimmed to the same length and case mouths are chamfered and deburred before neck turning.

 

[simonp]

Wow, I've not seen that before, at first, I thought it was a matter of you using the pilot with a cutting edge and rotating the brass as you pushed down but your pilot doesn't appear to have the cutting edge to remove the donut in the neck.

Are you using a mandrel on your brass beforehand? I anneal, mandrel, then turn the necks or alternatively I turn them after once firing and before cleaning - the carbon makes for a great dry lube. If I am turning necks on clean brass, I will use the imperial dry lube.

 

[FrenchPewPiou]

either use a Dremel with buffer and a good polish or chuck the pilot on a drill and use a cloth with polish on it. You will see it smooth out. Might have to do it a few times. Just watch the pilot and brass as you go, if it starts leaving marks, polish it again. I do this with mandrels too.

Adding: also make sure you chamfer the case mouth. I typically run brass on a 3 way cutter to make sure they are all trimmed to the same length and case mouths are chamfered and deburred before neck turning.

I didn't have anything else on hand so I tried the pilot on drill + cloth with some BoreTech Chameleon Polish gel but it didn't do anything (the light scratches are still present). I will get a proper polish paste tomorrow and try again.

I chamfer the case mouth, and I also tried on a brand new case that I only passed through the expander mandrel, same issue.

Wow, I've not seen that before, at first, I thought it was a matter of you using the pilot with a cutting edge and rotating the brass as you pushed down but your pilot doesn't appear to have the cutting edge to remove the donut in the neck.

Are you using a mandrel on your brass beforehand? I anneal, mandrel, then turn the necks or alternatively I turn them after once firing and before cleaning - the carbon makes for a great dry lube. If I am turning necks on clean brass, I will use the imperial dry lube.

Indeed there is no cutting edge on my pilot. Yes I'm using the K&M expander mandrel with some Redding Imperial Sizing Die Wax. I also have and tried the Redding Imperial Dry Lube (both on mandrel & on pilot) but with the same issue unfortunately .


Just to make sure, you guys don't have the slightest scratch inside your necks after neck turning?

 

[Evintos]

Never seen it it that deep and I also neck turn with K&M with Redding Imperial Sizing wax. Very light scratches on the other hand do appear and doesn't affect anything.

Edit - the amount of brass left on your K&M pilot is kind of a lot. What size expander mandrel and pilot are you using?

For reference, here's a pic of one of my pilots after neck turning 400 pieces of virgin brass, expanded using a .0025 mandrel + using .0025 pilot.

 

[FrenchPewPiou]

I polished both the pilot and mandrel, twice, with grit 500 polish paste. They are now both very shiny and clean, but still, there are light scratches... see the new video I just made. I don't "hear"/feel the scratches anymore though.

Never seen it it that deep and I also neck turn with K&M with Redding Imperial Sizing wax. Very light scratches on the other hand do appear and doesn't affect anything.

Edit - the amount of brass left on your K&M pilot is kind of a lot. What size expander mandrel and pilot are you using?

For reference, here's a pic of one of my pilots after neck turning 400 pieces of virgin brass, expanded using a .0025 mandrel + using .0025 pilot.

Thank you for your feedback! Are the scratches in my video above what you'd consider "light scratches"?

I use the K&M 6.5mm Expander Mandrel, brand new, and the K&m 6.5mm Pilot, brand new as well.

 

[Evintos]

I polished both the pilot and mandrel, twice, with grit 500 polish paste. They are now both very shiny and clean, but still, there are light scratches... see the new video I just made. I don't "hear"/feel the scratches anymore though.




Thank you for your feedback! Are the scratches in my video above what you'd consider "light scratches"?

I use the K&M 6.5mm Expander Mandrel, brand new, and the K&m 6.5mm Pilot, brand new as well.

Yes, in your new vid, that's how it looks on the ones I've turned in terms of depth. I don't feel any of mine with a paper clip.

In terms of visual amount there's less scratches overall on the ones I've turned. Unfortunately I don't have any personal pics for you to reference because I've applied a layer of Neolube #2 to all of my neck turned brass already. Using your vid as an example though, my cases visually look more like 'A' than 'B' at all angles of light with only 2-3 rings average at certain points/unevenly spaced out in the neck. Your 'B' shows that the rings are from case mouth and down to the shoulder. Hope I'm describing it adequately.

A few tips -

1. Apply the the sizing wax to both the inside case neck and the neck turn pilot.

2. Keep a little brush with the neck turn kit and brush the turner pilot and cutter every so often (it depends on how much you turn and how much brass particles there are) brush the turner clean.

3. if you're using the steel pilot (as opposed to the carbide pilot), don't let the pilot get hot if you're neck turning with the power adapter (especially if you're turning at "high" speed). If the pilot starts to feel warm. Stop, let it cool down. While it's cooling down, brush as much of the brass particles/bits away, wipe the pilot with a clean paper towel. Reapply a thin layer of the Redding Imperial sizing wax onto the pilot.

4. Keep the neck ID and turning pilot as close in diameter as possible. Example, You wouldn't want the turning pilot to be 0.001" larger in diameter than what you expanded the neck to. It would add extra friction.

 

[memilanuk]

Get a better lube. Sizing die wax is made for... sizing dies, not dealing with high speed rotary friction. Yes, it can work... until it doesn't. Sinclair / Brownell's used to sell a cutting oil that worked well, but was messy as hell and a right PITA to clean off. PMA and 21st Century both sell lubes specifically for neck turning. Of the two, I'm currently using the Delta Carbon No-Oil from 21st Century.

As mentioned... lube the insides of the case necks initially, then apply lube to the turning mandrel in between every case or two. Too much is better than not enough, in this case. Keep a chip/acid brush handy to clear away debris. Assuming you are using a variable speed drill, do not use it on the 'high speed' setting. If you're turning a larger batch, put some ice in a ziploc baggie, and set it in a bowl. When you set the turner down to change cases, set it on top of the baggie of ice. That's all it really takes to keep it cool, IME.

Whatever you're doing, you're burning off whatever lube you managed to get inside the necks / on the mandrel, which is causing it to heat up and gall. More lube, less speed.

And polished to 500 grit? You probably just ruined both. Order new.

 

[Baron23]

What would you use (to also avoid polishing it too much)?

Semichrome on a buffing wheel in a dremel or drill. Wow, I'm no machinist but 500 grit seems to be a bit much, no?

 

[simonp]

I didnt see that you were using a drill, that might explain why you are getting the results you are. I hand turn, slower yes, but a dash of dry lube is sufficient and I dont run into this issue. I tend to turn 20-30 cases at a time then move on to something else.

 

[XLR308]

I use a 12v drill on low speed exclusively for neck turning brass and have never seen anything like what you described and pictured.
The only main differences i see is i use 21st Century neck turning tools instead of K&M and shouldnt make any difference since both are quality tools.
I have allways used Lee sizing past as the lubricant with no noticable heating issues and i use Titanium Nitride coated turning arbors.

 

[straightshooter1]

I polished both the pilot and mandrel, twice, with grit 500 polish paste. They are now both very shiny and clean, but still, there are light scratches... see the new video I just made. I don't "hear"/feel the scratches anymore though.




Thank you for your feedback! Are the scratches in my video above what you'd consider "light scratches"?

I use the K&M 6.5mm Expander Mandrel, brand new, and the K&m 6.5mm Pilot, brand new as well.

Polishing does help! Imperial sizing wax helps a little, but there's other ways to lube that works better, for example: Delta Turning Lube from 21st Century; light weight synthetic motor oil works real well.

A couple of other things, you may already be aware of:

1. Size the brass to .001 larger ID than the turning mandrel.
2. Keep the heat down that's generated from any of the turning friction, excessive heat will cause the mandrel to expand and often results in that kind of galling.

 

[FrenchPewPiou]

Yes, in your new vid, that's how it looks on the ones I've turned in terms of depth. I don't feel any of mine with a paper clip.

In terms of visual amount there's less scratches overall on the ones I've turned. Unfortunately I don't have any personal pics for you to reference because I've applied a layer of Neolube #2 to all of my neck turned brass already. Using your vid as an example though, my cases visually look more like 'A' than 'B' at all angles of light with only 2-3 rings average at certain points/unevenly spaced out in the neck. Your 'B' shows that the rings are from case mouth and down to the shoulder. Hope I'm describing it adequately.

View attachment 8404669

A few tips -

1. Apply the the sizing wax to both the inside case neck and the neck turn pilot.

2. Keep a little brush with the neck turn kit and brush the turner pilot and cutter every so often (it depends on how much you turn and how much brass particles there are) brush the turner clean.

3. if you're using the steel pilot (as opposed to the carbide pilot), don't let the pilot get hot if you're neck turning with the power adapter (especially if you're turning at "high" speed). If the pilot starts to feel warm. Stop, let it cool down. While it's cooling down, brush as much of the brass particles/bits away, wipe the pilot with a clean paper towel. Reapply a thin layer of the Redding Imperial sizing wax onto the pilot.

4. Keep the neck ID and turning pilot as close in diameter as possible. Example, You wouldn't want the turning pilot to be 0.001" larger in diameter than what you expanded the neck to. It would add extra friction.

Thank you very much for your detailed reply! Very clear, thanks. I will make sure to follow your tips! I tried again with proper cutting oil, low speed, properly sized neck... it's the same result as my last vid. I ordered a new pilot and cutter just to see if it makes a difference.

Get a better lube. Sizing die wax is made for... sizing dies, not dealing with high speed rotary friction. Yes, it can work... until it doesn't. Sinclair / Brownell's used to sell a cutting oil that worked well, but was messy as hell and a right PITA to clean off. PMA and 21st Century both sell lubes specifically for neck turning. Of the two, I'm currently using the Delta Carbon No-Oil from 21st Century.

As mentioned... lube the insides of the case necks initially, then apply lube to the turning mandrel in between every case or two. Too much is better than not enough, in this case. Keep a chip/acid brush handy to clear away debris. Assuming you are using a variable speed drill, do not use it on the 'high speed' setting. If you're turning a larger batch, put some ice in a ziploc baggie, and set it in a bowl. When you set the turner down to change cases, set it on top of the baggie of ice. That's all it really takes to keep it cool, IME.

Whatever you're doing, you're burning off whatever lube you managed to get inside the necks / on the mandrel, which is causing it to heat up and gall. More lube, less speed.

And polished to 500 grit? You probably just ruined both. Order new.

Thank you for your explanations about the lube and speed/heat issues. As mentioned above, I tried with cutting oil, very low speed, it's cleaner but there are still scratches. I ordered a new pilot and cutter to see if it makes a difference.

About the 500 grit... yeah, now it's very shiny... it doesn't seem to make a big difference compared to before though (maybe they were already ruined...).

Semichrome on a buffing wheel in a dremel or drill. Wow, I'm no machinist but 500 grit seems to be a bit much, no?

@memilanuk seems to agree!

I didnt see that you were using a drill, that might explain why you are getting the results you are. I hand turn, slower yes, but a dash of dry lube is sufficient and I dont run into this issue. I tend to turn 20-30 cases at a time then move on to something else.

I'll also try by hand and keep you posted.

I use a 12v drill on low speed exclusively for neck turning brass and have never seen anything like what you described and pictured.
The only main differences i see is i use 21st Century neck turning tools instead of K&M and shouldnt make any difference since both are quality tools.
I have allways used Lee sizing past as the lubricant with no noticable heating issues and i use Titanium Nitride coated turning arbors.

Thank you for the feedback!

Polishing does help! Imperial sizing wax helps a little, but there's other ways to lube that works better, for example: Delta Turning Lube from 21st Century; light weight synthetic motor oil works real well.

A couple of other things, you may already be aware of:

1. Size the brass to .001 larger ID than the turning mandrel.
2. Keep the heat down that's generated from any of the turning friction, excessive heat will cause the mandrel to expand and often results in that kind of galling.

I bought a cutting oil. For the brass ID, I don't really have choice because I use the standard K&M expander mandrel for 6.5mm and nothing else is available here (in France).

 

[FrenchPewPiou]

Update!

I received the new K&M steel pilot today. I hand-turned (didn't use the drill this time) very slowly, barely pushing the handle, tried with cutting oil (inside and outside), then with Redding Imperial Bio-Green case lube (inside and outside)... same as before. There are light scratches. At the case mouth I can't feel them, but close to the shoulder I can feel them.

At this point I'm not sure if it's expected or if it's wrong then what's wrong...

Do you guys have this kind of scratches inside your cases necks? I did a new video below.



EDIT: I tried to "turn" the necks without touching the cutter (stopping before touching the cutter). I put the case onto the lubricated pilot, turn it (by hand) a few turns and then check. Well... scratches are already there. And it's a brand new pilot. No signs of any scratches after the mandrel expander step, they appear after turning onto the pilot. So are K&M pilot just bad or is this expected?

 

[Evintos]

Take and a pic of both the expander mandrel and pilot (remove them from the turner and die body), would like to see the laser marking.

If you have a micrometer, measure the diameter of the pilot and the mandrel, within 0.0001"

Edit - excluding the section closest to the case mouth, the rest looks like what I normally see. Which is like the one random scratch ring in the middle of the neck.

 

[FrenchPewPiou]

Take and a pic of both the expander mandrel and pilot (remove them from the turner and die body), would like to see the laser marking.

If you have a micrometer, measure the diameter of the pilot and the mandrel, within 0.0001"

The small numbers on the pilot are "23-11" and "23-04" on the expander mandrel if that matters.

I only have a caliper with a resolution of 0.0005" but I got 0.2630" for the pilot and 0.2640" for the expander mandrel. This makes me wonder: the Sinclair neck turning tool pilot is 0.262" and the expander mandrel 0.263" (so 0.001" smaller). Is one of them theoretically better?

 

[Evintos]

I'm wondering whether or not your expander is 0.2625" or 0.2630" and your pilot is .2645". A 1.5 to 2 thousandths difference would provide a lot of friction and that would give you more scratches than if you had a more closer matching pair. Default pilot may be a 0.2645" diameter.

@rustybend may be able to answer it.
https://www.snipershide.com/shootin...-6-5mm-pilot-too-large-is-it-just-me.7100526/

 

[straightshooter1]

The small numbers on the pilot are "23-11" and "23-04" on the expander mandrel if that matters.

I only have a caliper with a resolution of 0.0005" but I got 0.2630" for the pilot and 0.2640" for the expander mandrel. This makes me wonder: the Sinclair neck turning tool pilot is 0.262" and the expander mandrel 0.263" (so 0.001" smaller). Is one of them theoretically better?

View attachment 8405827

I've not had any experience with the K&M turner as I only have the Sinclair and PMA tool. When I first started turning necks, the pilot was steel and I had that problem with galling and quick heat build up. I switched out the steel pilot for a carbide pilot and have not had the galling problem since. Both my Sinclair and PMA turning pilots are carbide and neither produce any of those kinds of galling or scratches, and . . . I rarely use any lube. I should add that my brass is fired and annealed at least once, usually twice, before I turn the necks. The annealing reduces the amount of springback so they're not at tight on the pilot as when there is no annealing done.

 

[memilanuk]

So... been busy getting ready for an event next week. Needed to neck turn some cases, and because of this thread, decided it was a good excuse to stick a borescope down the mouth of one of the case necks.

Video clip

That's Alpha OCD .308 Win SRP brass, neck turned to 0.013" on a K&M setup - 0.308 expander mandrel, 0.307 turning pilot, then ran through a Bullet Central Micron F/L bushing sizing die with a 0.332 bushing to net a finished ID of 0.305. Case neck IDs were lubed with Delta Carbon No-Oil lube before expanding, and another quick swipe applied to the turning pilot between each case. Both the mandrel and the pilot have the original factory mirror polish finish.

I've turned more than a few necks for .223 Rem, 6BR, even 6.5-08 back in the day, and a metric $hitload of .308 Win over the years for FTR competition. I highly doubt the problem is on K&M's end.

 

[FrenchPewPiou]

I'm wondering whether or not your expander is 0.2625" or 0.2630" and your pilot is .2645". A 1.5 to 2 thousandths difference would provide a lot of friction and that would give you more scratches than if you had a more closer matching pair. Default pilot may be a 0.2645" diameter.

@rustybend may be able to answer it.
https://www.snipershide.com/shootin...-6-5mm-pilot-too-large-is-it-just-me.7100526/

I bought a micrometer and measured both:
- Mandrel: 0.2642in
- Pilot: 0.2629in
So I guess it's all good...

I've not had any experience with the K&M turner as I only have the Sinclair and PMA tool. When I first started turning necks, the pilot was steel and I had that problem with galling and quick heat build up. I switched out the steel pilot for a carbide pilot and have not had the galling problem since. Both my Sinclair and PMA turning pilots are carbide and neither produce any of those kinds of galling or scratches, and . . . I rarely use any lube. I should add that my brass is fired and annealed at least once, usually twice, before I turn the necks. The annealing reduces the amount of springback so they're not at tight on the pilot as when there is no annealing done.

View attachment 8405999View attachment 8406001

I bought the Sinclair tool with carbide pilot and carbide mandrel. Can't wait to try it out, but I got to wait a little because it comes from the US (to France) so it's going to take ~3-4 weeks before I can try it out. I will update this thread when it arrives for sure!

So... been busy getting ready for an event next week. Needed to neck turn some cases, and because of this thread, decided it was a good excuse to stick a borescope down the mouth of one of the case necks.

Video clip

That's Alpha OCD .308 Win SRP brass, neck turned to 0.013" on a K&M setup - 0.308 expander mandrel, 0.307 turning pilot, then ran through a Bullet Central Micron F/L bushing sizing die with a 0.332 bushing to net a finished ID of 0.305. Case neck IDs were lubed with Delta Carbon No-Oil lube before expanding, and another quick swipe applied to the turning pilot between each case. Both the mandrel and the pilot have the original factory mirror polish finish.

I've turned more than a few necks for .223 Rem, 6BR, even 6.5-08 back in the day, and a metric $hitload of .308 Win over the years for FTR competition. I highly doubt the problem is on K&M's end.

Thank you for the video and feedback! Do you use the steel pilot/mandrel or the carbine ones?

 

[memilanuk]

Steel. Most of mine predate the relative easy availability of carbide mandrels/pilots. The only carbide (K&M) ones I have are for reaming inside neck donuts.

 

[FrenchPewPiou]

Update! I received my Sinclair NT-4000 neck turning tool with carbide neck turning mandrel and carbide expander mandrel. Well... it works much better than the K&M kit! Now I almost don't have any scratches inside, and the few scratches are very very light (barely visible, can't feel them).