Expander Mandrel - Scratched brass

[Tony1320]

I wanted to try using an expander mandrel this year so I bought a 21st century titanium nitride turning mandrel. I read that it was normal to use dry so I tried it on virgin 308 palma brass but it scored the inside of the necks. Is this brass ruined or is it fine?

Should I be using imperial die sizing wax on the mandrel?

 

[Uncle Ed]

You should use some sort of lube on the mandrel so the case neck floats on a film of lube.

Also titanium nitride is a plating and I would rather have steel or preferably carbide. I bought a Hornady 9mm titanium nitride die and out of the box it scratched the cases, and none of my carbide dies ever scratched a case.

Again lube the mandrel and let the case neck "float" on a film of oil.

NOTE, look at your mandrel with a magnifying glass, and see if any brass is sticking to the mandrel and building up.

 

[Tony1320]

You should use some sort of lube on the mandrel so the case neck floats on a film of lube.

Also titanium nitride is a plating and I would rather have steel or preferably carbide. I bought a Hornady 9mm titanium nitride die and out of the box it scratched the cases, and none of my carbide dies ever scratched a case.

Again lube the mandrel and let the case neck "float" on a film of oil.

I will use imperial die sizing wax going forward

Are my scored cases ruined or just cosmetic?

 

[Tony1320]

You should use some sort of lube on the mandrel so the case neck floats on a film of lube.

Also titanium nitride is a plating and I would rather have steel or preferably carbide. I bought a Hornady 9mm titanium nitride die and out of the box it scratched the cases, and none of my carbide dies ever scratched a case.

Again lube the mandrel and let the case neck "float" on a film of oil.

NOTE, look at your mandrel with a magnifying glass, and see if any brass is sticking to the mandrel and building up.

There is brass residue on the mandrel, I wiped the mandrel down with alcohol but there still some scoring on it

 

[Uncle Ed]

Clean the mandrel with a strong copper solvent and remove as much brass as possible then polish the mandrel smooth.

In my opinion your cases are not ruined and still can be used.

NOTE, a stronge bore cleaner is one that if you sniff it your nose hairs fall out and you get whiplash from jerking your head back from the bottle.

 

[Tony1320]

Clean the mandrel with a strong copper solvent and remove as much brass as possible then polish the mandrel smooth.

In my opinion your cases are not ruined and still can be used.

NOTE, a stronge bore cleaner is one that if you sniff it your nose hairs fall out and you get whiplash from jerking your head back from the bottle.

I have sweets 7.62 I can try on it. Would iosso work to polish the mandrel?

That's good news thanks for the help

 

[Straightshooter1]

I think that manufacturers a purposefully taking advantage of consumer's ignorance when it comes to something like titanium nitride as a coating on some tools. Or, maybe some of them don't fully understand the properties of that coating either??? For a lot of tools, it just doesn't make a lot of sense to me for the coating when one finds out just what coating is actually designed to do. That is . . . to reduce friction under HIGH pressure, (which helps to reduce heat and prolong the life of cutting edges of tool . . . tools under HIGH pressure), like one can have with large drill bits drilling steel under a drill press. Without the high pressure, it doesn't really provide much of any lubricating qualities and therefore not must better than regular hardened steel. . . though the gold color is pretty. This is what I found out a couple years ago after some extensive research as I tried to find out if there was something better than steel mandrels and not as expensive as carbide ones. So . . . I grit my teeth going into my wallet and go with carbide whenever it's available, and it really does work well. . . even without lube.

 

[BenPerfected]

Another option is to spray your brass with One Shot Spray Lube including the inside of the necks. I use a custom Forester full length sizing die and then follow up with 1-2 K&M expander mandrels in .0005 increments as needed. If your neck walls are consistent, your bullet seating tension can also be very consistent. If your neck walls are close to perfect, you will only need a few expander mandrels in .0005 increments. If your neck thickness varies, another option is use a complete set of expander mandrels to control neck tension.
Ben

 

[AJC]

Did you chamfer the neck first? I would hope to do this dry as a final step right before powder and bullet, without yet another cleaning step. I plan to order the set for 308 from 21st and use the redding dry lube.

Uncle ed below posted a picture of the product i have and would recommend thanks

 

[Uncle Ed]

I have sweets 7.62 I can try on it. Would Iosso work to polish the mandrel?

That's good news thanks for the help

Iosso might work just fine but so will ultra fine wet and dry sandpaper. I say this because the titanium nitride coating might be rough and pickup brass if not smoothed down.

Grit 1500 2000 2500 3000 5000 7000 High Precision Polishing Sanding Wet/dry Abrasive Sandpaper Sheets - Germany, Pack of 12
https://www.amazon.com/dp/B075L2D9HG/?tag=accuratescom-20

NOTE, the marks inside your case neck in your photos are straight and run the length of the neck. And you do not have spiral marks from rotational turning. Meaning your marks were caused when expanding the necks and not turning the necks.

I dip my cases in graphite neck lube below to prevent scratching and galling when expanding my necks with a expander die.

Question, are you wet tumbling these cases, in your photos I see small brass flakes around the case mouth. If you are not wet tumbling then the inside of the case mouths have a rough edge and it is flaking off.

 

[jepp2]

I wiped the mandrel down with alcohol but there still some scoring on it

Just spin it in a drill and use some Flitz on a paper towel and it will come right off.

 

[foxguy]

In regards to your brass, I would.....

try Polishing the scratches out on the inside of the necks with some Steel wool wrapped around on a Nylon or Bronze Caliber brush. Place some steel wool around the Brush, place the brush in a power Drill and spin the brush with the steel wool on it into the neck. I would suspect 3-7 seconds would be long enough.

000 or 0000 Steel wool.

000 Extra Fine For buffing, polishing, and removing. Polishes stainless steel, aluminum, copper, brass and zinc. ​

You will want to get all of the Steel Wool out of the brass when completed, You can use compressed air or rinse them out good and let them dry.

 

[oldduc]

I have sweets 7.62 I can try on it. Would iosso work to polish the mandrel?

I have used plain steel, titanium nitride, and carbide mandrels over the years. They will all pick up brass and/or carbon out of the case necks, eventually. The carbide doesn't really do a better job than plain steel and still requires lube, in my experience. When they get dirty, just spin them and use 0000 steel wool and they cleanup easily. I never use any non-dry lube in case necks. Too much of a PITA to clean out. I am using graphite now and have used white mica powder in the past. The graphite will leave a thin coating that helps seat the bullets easily.

 

[spclark]

Clean the mandrel with a strong copper solvent and remove as much brass as possible then polish the mandrel smooth.

In my opinion your cases are not ruined and still can be used.

NOTE, a stronge bore cleaner is one that if you sniff it your nose hairs fall out and you get whiplash from jerking your head back from the bottle.

That's what I do.

I use SS mandrels & still see some brass after awhile. IMHO the scratches you see inside necks don't affect their longevity. I have Palma brass I've fired & re-sized for going on 7 or 8 years that will still shoot X's at 600 and 1000 yards if I'm paying attention when they go off.

The copper solvent thing is a good idea for getting brass off. Polishing the mandrels will help some but remember a mirror-smooth mandrel surface has a greater tendency to collect brass just like a mirror-polished bore will collect copper. If you can find 800 or 1,000 grit emory cloth that's better than any polish for returning the surface to something like what it left the factory with. Don't use it dry either, use a bit of oil to wet it and the mandrel you're using.

 

[Bamban]

Get a regular steel mandrel and have it Melonited. Not carbide hard, it is the next best thing. Melonited surfaces are tough enough that file won't bite them.

 

[foxguy]

Before using the expanding mandrel did you inside chamfer the new brass?

 

[Petros284]

Always use lube with all of our mandrels in stainless steel or TiN coated. I have found Ballistol spray to work wonders. Imperial wax very lightly works well too.

As for WHY we offer the TiN coating? It aids in reducing friction and in turn reduces galling of your brass while using a proper lubricant.

 

[Willie]

Late to the party, but the OP's pic looks like new, tight necks. I would suggest the vertical marks could possibly be caused by expansion to some degree. Still, I always use dry lube. It makes a big difference in pressure on the press handle.

 

[Webster]

Did you chamfer the neck first? I would hope to do this dry as a final step right before powder and bullet, without yet another cleaning step. I plan to order the set for 308 from 21st and use the redding dry lube.

Uncle ed below posted a picture of the product i have and would recommend thanks

I wanted to try using an expander mandrel this year so I bought a 21st century titanium nitride turning mandrel. I read that it was normal to use dry so I tried it on virgin 308 palma brass but it scored the inside of the necks. Is this brass ruined or is it fine?

Should I be using imperial die sizing wax on the mandrel?

Had a similar problem. Chamfer the case i.d and o.d. Lube and you won't have any problem. All new cases have little nibs of brass high spots on the neck end probably because they don't trim the case ends. If you don't chamfer enough little high pieces of the brass break free and get dragged down the the neck. Pieces ajdhere to a mandrel or sizing die and cause scratches on every neck. From your pictures you have a lot of brass adhering to your mandrel. I wouldn't polish the mandrel unless it's a last resort. Soak in Sweets. Ammonia won't damage steel don't know about TiN.

I didn't chamfer some cases enough on the o.d. My sizing die broke tiny pieces of brass off the necks. Eventually I had brass adhering to the die. The scratches were on the necks and body. I removed most of it with Sweets then polished the die by spliting a wooden dowell and 600 or 1200 grit sand paper wrapped around the dowell in an electric drill. I didn't try to remove every trace of copper. I just made it smooth with no obvious high spots. I never bought special lubes. I prefere petroleum oils. Cheap and they are the best lube. Currently using petroleum based Hydraulic Fluid from AutoZone. About $8 a quart. I roll my cases on a pad.

 

[rwj]

What was the difference in the mandrel OD and case neck ID before expanding?