Polish expander ball

GaryO7 · February 10, 2014, 01:23 PM

I guess the theory is to polish the expander ball in our sizeing die to minimize case neck stretching. Does this sound valid? What say you? Thanks...

NoSecondBest · February 10, 2014, 02:39 PM

I haven't done it yet in almost fifty years of reloading. I'd suggest dipping the neck in powdered graphite or lightly lubing the inside of the case neck if it's sticking on the expander ball. I've never seen the expander ball stretch cases or cause any problems other than making the handle stick a little. I think you're fixing a problem that doesn't exist. Also, polishing the ball will/could reduce its diameter. Minutely, but less never the less.

wogpotter · February 10, 2014, 02:46 PM

I've always done this on my rifle dies because I don't like to crimp so I use the method to increase neck tension instead.
I just spin the heck out of it in a power drill using green ScotchBrite as a fine abrasive. I did note it made the stroke a little easier as well even though it wasn't the main reason for it.

Eppie · February 10, 2014, 05:19 PM

Quote:

I guess the theory is to polish the expander ball in our sizeing die to minimize case neck stretching. Does this sound valid?

If accuracy requirements are reasonably low, then the answer is yes.

AllenJ · February 10, 2014, 05:58 PM

If done properly it would help some. What brand dies are you using?

BumbleBug · February 10, 2014, 06:41 PM

Sinclair International's Book: "Precision Reloading & Shooting Handbook" devotes several pages & a number of photo's on polishing expander balls to improve the quality of reloads when using regular sizing dies. They recommend using a hard sharpening stone with the die stem chucked in a drill. They emphasis that what you are trying to do is smooth & taper the edges while avoiding any reduction in the ball's diameter. A final polish with super-fine emery cloth is performed to complete the job. Of course, lube inside case necks is recommended.

FWIW...

..bug

Mike / Tx · February 10, 2014, 06:51 PM

Quote:

If accuracy requirements are reasonably low, then the answer is yes.

While I do have quite an assortment of different dies from different makers, I have also found that with some the expander ball benefited greatly from a light polishing. Some even needed a bit more than that.

While it usually isn't necessary with most of today's die sets, there was a time when the tooling simply wasn't up to the higher standards they are nowadays.

Even so if you want a smidgen more neck tension you can polish them down a touch. As long as your not going after them with a bastard file or 100gr emery cloth you should be fine.

As for accuracy I haven't found on instance where it was degraded by what little polishing I had done, and in some cases it actually improved. Adding to this I have also dropped the diameter of handgun expander balls .001 to .002" to get a better case tension than what they would do to start with.

It is certainly not unheard of for something mass produced to come out slightly over what you actually needed.

jaguarxk120 · February 10, 2014, 08:46 PM

You will be farther ahead if you clean the case necks before sizing. A brass brush chucked in a drill motor turning slowly is enough to remove any carbon/fouling in the case neck.

I wash my case's after sizing so when sizing I lube the case necks in a nylon brush that has a few drops of oil on it. That's enough to allow the sizing ball to slip through the neck easily.

I also tumble my case's with stainless steel pins, my case's come out like factory new clean inside and out.

jepp2 · February 10, 2014, 09:01 PM

I polish the expanders and lube the necks. Keeps the necks straighter. But for the calibers I load more of, I convert to carbide expanders. Those REALLY reduce the friction.

Since I use Redding body dies and Lee collet dies, I find that neck stretching and being pulled off axis is much less common now.

Eppie · February 10, 2014, 09:48 PM

Gary,
Most people (me included) when they first start reloading use the expander ball that comes with the die. However, after you've been reloading a while you discover that your ammo is not as accurate as you'd like and you decide to improve it. That opens Pandora's box and you quickly learn that the expander ball maybe affecting the accuracy (there's that word again) of your beloved reloads. It does, so you learn more about case necks..... "Come into my parlor says the spider to the fly."

It's a very interesting journey and there is lots to be learned and cherished. however, before you go down that road make sure you have the 1. money, 2. time and 3. inclination/intelligence/persistence to see it through. Two out of three won't cut it.

I've enjoyed it, I hope you will too. That doesn't mean that I didn't have my share of frustration along the way, but after you overcome it, you'll feel so much better.

Kevin Rohrer · February 10, 2014, 09:51 PM

Quote:

polish the expander ball

Never heard of a Polish expander ball. Nothing against the Poles, but I always buy American.

Wallyl · February 11, 2014, 10:40 AM

I have useing very fine sandpaper (1,000 grit) ..after you use it awhile, you will see that it will have minute longitudinal scratches on it. If you polish them out, they will reappaer after using it a short while...IOW nothing is gained from doing so in my experience.

Have some carbide expander buttons for a no. of CF rifle calibers..they don't have any scratches on them. But nobody that I know makes expander buttons out of carbide for pistol calibers.

Bart B. · February 11, 2014, 12:53 PM

I've measured case neck length from shoulder to mouth after it's come out of a gelded (ball removed) full length sizing die and compared that to the same dies that are not gelded. Both staring out at the same over all length. Insiginicant change in neck length when standard and polished balls are used.

Note the ability to make finely machined and smoothed metal parts has not changed much over the years. Take a look at some of the Swiss mechanical watch parts made back in the 1930's and 1920's. They're finished a lot smoother that virtually all expander balls these days.

Fired case necks get longer when they're sized down by the die. A bit longer if the case shoulder's set back, too. If the ball has a lot of resistance to the neck, it's possible to pull part of the case shoulder forward which can make the case tight in the chamber and the bolt closes with more effort.

February 10, 2014, 01:23 PM	#1
GaryO7 Member Join Date: November 14, 2007 Location: Roseville, CA Posts: 48	Polish expander ball I guess the theory is to polish the expander ball in our sizeing die to minimize case neck stretching. Does this sound valid? What say you? Thanks... __________________ Gary NRA Member

February 10, 2014, 02:46 PM	#3
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	I've always done this on my rifle dies because I don't like to crimp so I use the method to increase neck tension instead. I just spin the heck out of it in a power drill using green ScotchBrite as a fine abrasive. I did note it made the stroke a little easier as well even though it wasn't the main reason for it. __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”

February 10, 2014, 09:01 PM	#9
jepp2 Senior Member Join Date: December 24, 2008 Location: Loveland, CO Posts: 1,476	I polish the expanders and lube the necks. Keeps the necks straighter. But for the calibers I load more of, I convert to carbide expanders. Those REALLY reduce the friction. Since I use Redding body dies and Lee collet dies, I find that neck stretching and being pulled off axis is much less common now. __________________ NRA Benefactor Life member

February 10, 2014, 09:48 PM	#10
Eppie Senior Member Join Date: January 7, 2010 Location: Houston, TX Posts: 802	Gary, Most people (me included) when they first start reloading use the expander ball that comes with the die. However, after you've been reloading a while you discover that your ammo is not as accurate as you'd like and you decide to improve it. That opens Pandora's box and you quickly learn that the expander ball maybe affecting the accuracy (there's that word again) of your beloved reloads. It does, so you learn more about case necks..... "Come into my parlor says the spider to the fly." It's a very interesting journey and there is lots to be learned and cherished. however, before you go down that road make sure you have the 1. money, 2. time and 3. inclination/intelligence/persistence to see it through. Two out of three won't cut it. I've enjoyed it, I hope you will too. That doesn't mean that I didn't have my share of frustration along the way, but after you overcome it, you'll feel so much better. __________________ "Socialized Medicine is the Keystone to the Arch of the Socialist State.” -Vladimir Lenin "I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them." - Thomas Jefferson (An early warning to Obama care) Last edited by Eppie; February 10, 2014 at 09:54 PM.

February 11, 2014, 12:53 PM	#13
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	I've measured case neck length from shoulder to mouth after it's come out of a gelded (ball removed) full length sizing die and compared that to the same dies that are not gelded. Both staring out at the same over all length. Insiginicant change in neck length when standard and polished balls are used. Note the ability to make finely machined and smoothed metal parts has not changed much over the years. Take a look at some of the Swiss mechanical watch parts made back in the 1930's and 1920's. They're finished a lot smoother that virtually all expander balls these days. Fired case necks get longer when they're sized down by the die. A bit longer if the case shoulder's set back, too. If the ball has a lot of resistance to the neck, it's possible to pull part of the case shoulder forward which can make the case tight in the chamber and the bolt closes with more effort. Last edited by Bart B.; February 11, 2014 at 01:10 PM.

February 10, 2014, 02:39 PM	#2
NoSecondBest Senior Member Join Date: December 7, 2009 Location: Western New York Posts: 2,736	I haven't done it yet in almost fifty years of reloading. I'd suggest dipping the neck in powdered graphite or lightly lubing the inside of the case neck if it's sticking on the expander ball. I've never seen the expander ball stretch cases or cause any problems other than making the handle stick a little. I think you're fixing a problem that doesn't exist. Also, polishing the ball will/could reduce its diameter. Minutely, but less never the less.

February 10, 2014, 05:58 PM	#5
AllenJ Senior Member Join Date: December 11, 2009 Location: Northern California Posts: 1,766	If done properly it would help some. What brand dies are you using?

February 10, 2014, 06:41 PM	#6
BumbleBug Senior Member Join Date: March 11, 2013 Location: Near Heart of Texas Posts: 870	Sinclair International's Book: "Precision Reloading & Shooting Handbook" devotes several pages & a number of photo's on polishing expander balls to improve the quality of reloads when using regular sizing dies. They recommend using a hard sharpening stone with the die stem chucked in a drill. They emphasis that what you are trying to do is smooth & taper the edges while avoiding any reduction in the ball's diameter. A final polish with super-fine emery cloth is performed to complete the job. Of course, lube inside case necks is recommended. FWIW... ..bug

February 10, 2014, 08:46 PM	#8
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,619	You will be farther ahead if you clean the case necks before sizing. A brass brush chucked in a drill motor turning slowly is enough to remove any carbon/fouling in the case neck. I wash my case's after sizing so when sizing I lube the case necks in a nylon brush that has a few drops of oil on it. That's enough to allow the sizing ball to slip through the neck easily. I also tumble my case's with stainless steel pins, my case's come out like factory new clean inside and out.

February 11, 2014, 10:40 AM	#12
Wallyl Senior Member Join Date: September 8, 2011 Posts: 255	I have useing very fine sandpaper (1,000 grit) ..after you use it awhile, you will see that it will have minute longitudinal scratches on it. If you polish them out, they will reappaer after using it a short while...IOW nothing is gained from doing so in my experience. Have some carbide expander buttons for a no. of CF rifle calibers..they don't have any scratches on them. But nobody that I know makes expander buttons out of carbide for pistol calibers.