ANY ACTUAL TESTING on neck hardness before/after ss pin cleaning ?

[retired]

the samples were in ss cleaning media for 4 hours
'POLISHED' is not a word i use with ss pins..cleaned is the word.

Did they say the case was pin polished. I have done microhardness for 45 years. It's impossible to get closer than several thousanths


Good point the flat sides of the pins touch the cases not the ends.

 

[divingin]

AMP said that testing the hardness of the neck while the case was on a mandrel showed hardening occurred. When they repeated the test on the cross section of the neck, they showed that the hardness was microscopically thin and confined to the outer surface. This is entirely consistent from some slight work hardening of the case exterior due to the impact of the pins.

I would hazard a guess that the hardening was due to impact, either the pins or case to case impact. In thinking about it, the case to case scenario would probably generate more force.

 

[retired]

the cases and pins FLOAT in a sea of pins.
impact is very minimal..as the testing showed, same for look to the surface.

I would hazard a guess that the hardening was due to impact, either the pins or case to case impact. In thinking about it, the case to case scenario would probably generate more force.

 

[suasponte]

No work hardening can occur from tumbling brass in stainless media.

 

[retired]

no "significant" work hardening can occur in normal pin cleaning.
BUT
surface hardening did occur...insignificant to reloading.
documented by AMP.

No work hardening can occur from tumbling brass in stainless media.

 

[amlevin]

To me, any work hardening from tumbling in SS Pin's is a non issue. I tumble first and then anneal. Takes care of any perceived issue with hardening AND my cases get nice and dry REAL QUICK

 

[stifffingers]

To me, any work hardening from tumbling in SS Pin's is a non issue. I tumble first and then anneal. Takes care of any perceived issue with hardening AND my cases get nice and dry REAL QUICK

A side note, tumbling in a large volume tumbler like the Thumbler will change the case mouths by they being thrust against each other when they go over the top and land on anything, cases or pins. The result is a peening of the case mouth, you can measure it for your self. This is why you should neck size after tumbling. However the neck sizing will take care of the outside diameter of the neck, but the peening also altered the inside of the neck. You have to chamfer the inside neck, if you don't and seat a bullet it will push the extra brass that reduced the inside diameter outward and now the loaded round is oversized at the neck. If you are a Benchrest shooter with tight neck chambers the bullets won't chamber and you wasted a trip to the range. It happened to me. I have a .263 chamber and the rounds were .265, they should be .261....Thus I returned the Thumblers tumbler and chose the Harbor Freight dual canister instead. 50 cases in each canister so I can tumble without mixing lots. Large volume units are great for most shooters but not for group,F class, 1K and such.

 

[retired]

If this is happening, then i believe, you do not have the correct mix of brass water and pins.
there should never be weight bearing impact.
operator error.
IMHO

A side note, tumbling in a large volume tumbler like the Thumbler will change the case mouths by they being thrust against each other when they go over the top and land on anything, cases or pins. The result is a peening of the case mouth, you can measure it for your self. This is why you should neck size after tumbling. However the neck sizing will take care of the outside diameter of the neck, but the peening also altered the inside of the neck. You have to chamfer the inside neck, if you don't and seat a bullet it will push the extra brass that reduced the inside diameter outward and now the loaded round is oversized at the neck. If you are a Benchrest shooter with tight neck chambers the bullets won't chamber and you wasted a trip to the range. It happened to me. I have a .263 chamber and the rounds were .265, they should be .261....Thus I returned the Thumblers tumbler and chose the Harbor Freight dual canister instead. 50 cases in each canister so I can tumble without mixing lots. Large volume units are great for most shooters but not for group,F class, 1K and such.

 

[stifffingers]

If this is happening, then i believe, you do not have the correct mix of brass water and pins.
there should never be weight bearing impact.
operator error.
IMHO

Followed the instructions to a tee. Since then there have been many articles on this happening if you are not tumbling large amounts of brass. That's the reason for the small canisters on the Harbor Freight unit.

 

[retired]

so you have results that AMP did not duplicate in their test.
AMP has no dog in the fight.
if you followed instructions to a t why do you have a problem and they did not ??
i'll stick with my reply.

Followed the instructions to a tee. Since then there have been many articles on this happening if you are not tumbling large amounts of brass. That's the reason for the small canisters on the Harbor Freight unit.

 

[stifffingers]

so you have results that AMP did not duplicate in their test.
AMP has no dog in the fight.
if you followed instructions to a t why do you have a problem and they did not ??
i'll stick with my reply.

If you read my post properly, it has nothing to do with hardness of the neck. As I stated "as a side note". This has nothing to do with AMP or testing hardness, it refers to tumbling small amounts of brass (100) cases in a large volume tumbler. Try it, measure your case mouths inside and out, then tumble for two hours and measure the mouths again. Not the case necks, just the case mouths. Benchrest shooters don't mix their brass lots. We keep tract of every time we reload each box of 50. I was tumbling 50 6PPC and 50 6BR in a Thumbler tumbler, 5 lbs. of pins, water up to 1 inch of top per directions. If the unit had another 300 or 500 cases in it, the peening would not have happened. With the Harbor Freight unit their is only enough room for 50 cases in each canister. I too will stay with the meaning of my first post. The thread started with a question of cleaning with ssPins and hardening of the necks. So I thought while everyone's attention is on tumbling, maybe they should be aware of a 'rare' but absolute problem that could occur. As far as your weight bearing impact theory how many case mouths have you dinged up when they hit something. It doesn't take much. My cases weren't dinged just slightly peened...On the home page do a search for "case neck peening". 140 results.