Honing the neck of a full length sizing die
- Thread starter jepp2
- Start date
I don't have any answers for you Jepp but I'd like to follow the thread.
Is it your intent to open the neck portion of the die to eliminate having to pull an expander ball up through the case neck where you end up with a dedicated "bushing" die?
If yes, you will have to know a lot about the chamber in your gun and you need to be certain your brass neck thickness is consistent piece to piece.
Is it your intent to open the neck portion of the die to eliminate having to pull an expander ball up through the case neck where you end up with a dedicated "bushing" die?
If yes, you will have to know a lot about the chamber in your gun and you need to be certain your brass neck thickness is consistent piece to piece.
Brian Pfleuger
Moderator Emeritus
jepp2 said:
No way to know without your brass.
Neck thickness is probably around 0.015-0.0165, give or take. At least that's what my Norma .243 brass runs.
If you're going to hone the neck out on the die, you'll be needing to uniform/turn the necks too.
If you neck thickness was 0.015 a .250 hone would be just about perfect. 0.250-(.015*2)=0.221
What to do to open up a FL die's neck..... more or less... without that hone.
Read through this 3 or 4 times to memorize the process before you acutally do it. Chances of goofing are reduced by 97.5 percent. Using a lathe spins the die chamber on its axis; using a hand drill with the hone/lap in it is hard to keep the opened up die neck straight.
You may want to practice and learn on a junk die; I'm glad I did.
1. Measure the neck diameter of 10 loaded rounds of the same ammo lot; write down the largest diameter to the nearest .0001". Don't loose that paper you wrote it down on.
2. Strip a die then chuck it up bottom out in a lathe headstock.
3. Saw a 1 inch fine groove in the tip of a wood dowel about 1/16 or 1/32 inch smaller than the number on that paper in step one.
4. Get some 600 grit emery paper for metal, then insert a strip of it about 1 inch wound around the dowel so its diameter is about .001 inch larger than that number in step 1.
5. Turn the lathe in the direction that won't unwrap the emery paper off the dowel; speed about 200 rpm.
6. Hold the emery paper onto the dowel then push it back and forth into and out of the die's neck for several strokes.
7. Turn the lathe off, clean out the die, then use a hole micrometer to see what the die's neck diameter is.
8. Repeat steps 7 and 8 over and over until you get the feel of what you're doing. Then go on to step 9.
9. Stop lapping out the die when its neck diameter's about .002" less than what's on that now crumpled piece of paper. Depending on the case brass properties and thickness, you may need to open up the die's neck to only .003" less than that of a loaded round's neck. Buy a couple of extra dies at a gun show cheap, then make a set in .001" steps.
10. Clean up your mess and resize some cases with that die, but don't put the expander ball back into it.
Using a hone as Unclenick mentioned is the same except it's used instead of an emery wrapped dowel.
Forster hones their own dies for ten bucks a pop. Just tell them what neck diameter you die needs and they do it; very well indeed.
Read through this 3 or 4 times to memorize the process before you acutally do it. Chances of goofing are reduced by 97.5 percent. Using a lathe spins the die chamber on its axis; using a hand drill with the hone/lap in it is hard to keep the opened up die neck straight.
You may want to practice and learn on a junk die; I'm glad I did.
1. Measure the neck diameter of 10 loaded rounds of the same ammo lot; write down the largest diameter to the nearest .0001". Don't loose that paper you wrote it down on.
2. Strip a die then chuck it up bottom out in a lathe headstock.
3. Saw a 1 inch fine groove in the tip of a wood dowel about 1/16 or 1/32 inch smaller than the number on that paper in step one.
4. Get some 600 grit emery paper for metal, then insert a strip of it about 1 inch wound around the dowel so its diameter is about .001 inch larger than that number in step 1.
5. Turn the lathe in the direction that won't unwrap the emery paper off the dowel; speed about 200 rpm.
6. Hold the emery paper onto the dowel then push it back and forth into and out of the die's neck for several strokes.
7. Turn the lathe off, clean out the die, then use a hole micrometer to see what the die's neck diameter is.
8. Repeat steps 7 and 8 over and over until you get the feel of what you're doing. Then go on to step 9.
9. Stop lapping out the die when its neck diameter's about .002" less than what's on that now crumpled piece of paper. Depending on the case brass properties and thickness, you may need to open up the die's neck to only .003" less than that of a loaded round's neck. Buy a couple of extra dies at a gun show cheap, then make a set in .001" steps.
10. Clean up your mess and resize some cases with that die, but don't put the expander ball back into it.
Using a hone as Unclenick mentioned is the same except it's used instead of an emery wrapped dowel.
Forster hones their own dies for ten bucks a pop. Just tell them what neck diameter you die needs and they do it; very well indeed.
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I appreciate the response! But some of your input seems different than my experience?
I use bushing dies and don't have to turn or uniform necks.
After posting, I did more searching and found a .250" flex cylinder head hone (for valve guides) that can hone diameters from .215" to .260". That should cover my range.
Why am I doing this? I am loading for a 222 Rem Mag. I use Redding body dies and Lee collets on everything else. Since I can't buy a Redding body die, I am going to take a full length sizing die and start to open it up. On the way I will stop at the point I can size without using the expander. I expect to open it up to the same bore as the body dies for .224 bullets (around .260"). So that is my project.
Brian Pfleuger
Moderator Emeritus
It depends on how demanding you are on consistent neck tension. Varying neck wall thickness will mean varying inside diameters, which means varying neck tension.
BTW, a quick glance at the case dimensions tells me you could also just cut 0.078" off a .22-250 collet.
BTW, a quick glance at the case dimensions tells me you could also just cut 0.078" off a .22-250 collet.
Run this through my mind about two weeks ago. Well when you use a expander in my RCBS FL dies, resize .002 for bolts or .004 for autos (which I don't have) and work up a load and can shoot same ragged hole in hunting rifle, I don't see or think I can get any more accurate. Seems like a waste of time for nothing to me. That's if we're talking accuracy.
Forster supposedly uses Hardinge collet lathes to hone out the sizer die necks. That would be the fast way to get low run out.
I have honed dies in the 4 jaw with shims. It is as hard or harder to set up than chambering a rifle. I prefer to pay Forster.
I sent my 6mmBR, 257RAI, 30-30, 308, 30-06, 8mm, and 338WM all at once to cut down on shipping.
Forster does Bonanza too, so let's assume that is where they got those expensive lathes.
For each new rifle cartridge I like to get a Forster set and a Lee collet neck die.
I have also started making dies.
Necking down brass necks is best done in 10% change or less steps.
With 7/8-14 threaded rod, one can make neck dies in a few minutes on the a lathe to any size desired.
I have honed dies in the 4 jaw with shims. It is as hard or harder to set up than chambering a rifle. I prefer to pay Forster.
I sent my 6mmBR, 257RAI, 30-30, 308, 30-06, 8mm, and 338WM all at once to cut down on shipping.
Forster does Bonanza too, so let's assume that is where they got those expensive lathes.
For each new rifle cartridge I like to get a Forster set and a Lee collet neck die.
I have also started making dies.
Necking down brass necks is best done in 10% change or less steps.
With 7/8-14 threaded rod, one can make neck dies in a few minutes on the a lathe to any size desired.
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Brian, neck wall variance up to .001" seems to me as totally acceptable. That'll put bullets no more than .0005" off the bore axis when case necks are well centered on case shoulders. Gelded full length sizing dies do that to fired cases.
= = = = = =
If you don't have a lathe, I suggest setting up something like this to keep the tool head straight in the die's neck:
It's a 7/8x14 nut with a .308 Win. FL die on the left and a ruined .243 Win FL die on the right. An M1 cleaning rod section fits good in the .243 die's neck to keep the tool axis well aligned with the .308 die's axis. A hone or other head's screwed into the rod section's female end.
= = = = = =
If you don't have a lathe, I suggest setting up something like this to keep the tool head straight in the die's neck:
It's a 7/8x14 nut with a .308 Win. FL die on the left and a ruined .243 Win FL die on the right. An M1 cleaning rod section fits good in the .243 die's neck to keep the tool axis well aligned with the .308 die's axis. A hone or other head's screwed into the rod section's female end.
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"BTW, a quick glance at the case dimensions tells me you could also just cut 0.078" off a .22-250 collet."
Brian can you expound on this? You're talking about the faceted insert that pushes down on the mandrel ... correct? Or are you talking about the tubular piece that sticks out the bottom of the die that makes contact with the shell holder?
Brian can you expound on this? You're talking about the faceted insert that pushes down on the mandrel ... correct? Or are you talking about the tubular piece that sticks out the bottom of the die that makes contact with the shell holder?
Brian Pfleuger
Moderator Emeritus
Well, both actually. If you cut the collet you'd have to shorten the decapping pin by the same amount. Not the easiest thing in the world but not really any harder than honing a die
Unclenick's reference to Flex Hone tools is in post 17 on this thread:
http://thefiringline.com/forums/showthread.php?t=543610&highlight=hone+die
http://thefiringline.com/forums/showthread.php?t=543610&highlight=hone+die
I think that the 0.0001" concentricity and parallel measurements dialing in with a spud and Intrepid test indication when chambering a rifle may be overkill.
That is because the eccentricity of the chamber is consistent, and flings the off bore center center of mass of the bullet into the same small hole in the target.
But when dealing with the eccentricity of ammo, that is more important, as the bent ammo is randomly oriented when inserted into the chamber.
The bullet center of mass his then, upon escapement from the muzzle, flung in random directions making a large group in the target.
No gunsmith would tolerate the sandpaper on a stick type methods described above to open a die neck, to be used on a chamber neck, where it would make a lot less difference.
The math is explained in:
American Rifleman" with article copyrights from 1950 - 1968
"Gauging Bullet Tilt" By A. A. ABBATIELLO
That is because the eccentricity of the chamber is consistent, and flings the off bore center center of mass of the bullet into the same small hole in the target.
But when dealing with the eccentricity of ammo, that is more important, as the bent ammo is randomly oriented when inserted into the chamber.
The bullet center of mass his then, upon escapement from the muzzle, flung in random directions making a large group in the target.
No gunsmith would tolerate the sandpaper on a stick type methods described above to open a die neck, to be used on a chamber neck, where it would make a lot less difference.
The math is explained in:
American Rifleman" with article copyrights from 1950 - 1968
"Gauging Bullet Tilt" By A. A. ABBATIELLO
I know its not likely you will have access to one,but just for fun,there is a machine called a Sunnen Hone.
Parts are often machined with precision holes slightly undersize,then heat treated.Then the hone brings them to size and roundness.
A precision ring gage is used to calibrate an air gage.This is used to check progress and form(taper,belling,jugging)Final size is confirmed with plug gages.
The hone machine is pretty much a spindle over a coolant pan.Speeds are set per a chart and step pulleys.
The spindle is loaded with a mandrel of appropriate size.The mandrel is fitted with a stone specific to the material and finish desired.
There is a drawbar in the spindle which connects to the mandrel which causes the stone to cut larger.
The stone is first dressed with a dressing sleeve,and and some cutting pressure/size parameters are set.
The part is slipped over the mandrel,coolant turned on,a foot pedal controls spindle start.
I might have run one of those a bit.
Clark,FWIW,these parts would be hand held,self aligning on the mandrel.The hone followed the original axis of the hole.
And,as far as honing on a Hardinge...there are a variety of Harding lathes,some just secondary operation machines.
But,on a full fledged HLV toolroom lathe,one shop I worked in,it was a firing offense to use any abrasive product,even a piece of wet/dry paper,while using the lathe.
Not everyone uses them to hone dies.Maybe Forster does,I don't know.
Parts are often machined with precision holes slightly undersize,then heat treated.Then the hone brings them to size and roundness.
A precision ring gage is used to calibrate an air gage.This is used to check progress and form(taper,belling,jugging)Final size is confirmed with plug gages.
The hone machine is pretty much a spindle over a coolant pan.Speeds are set per a chart and step pulleys.
The spindle is loaded with a mandrel of appropriate size.The mandrel is fitted with a stone specific to the material and finish desired.
There is a drawbar in the spindle which connects to the mandrel which causes the stone to cut larger.
The stone is first dressed with a dressing sleeve,and and some cutting pressure/size parameters are set.
The part is slipped over the mandrel,coolant turned on,a foot pedal controls spindle start.
I might have run one of those a bit.
Clark,FWIW,these parts would be hand held,self aligning on the mandrel.The hone followed the original axis of the hole.
And,as far as honing on a Hardinge...there are a variety of Harding lathes,some just secondary operation machines.
But,on a full fledged HLV toolroom lathe,one shop I worked in,it was a firing offense to use any abrasive product,even a piece of wet/dry paper,while using the lathe.
Not everyone uses them to hone dies.Maybe Forster does,I don't know.
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Bart B. thanks for the link, that is exactly the thread I was looking for but couldn't find.
I have a Lee collet die for the 222 Rem Mag. So I already have that covered.
Today I was sizing some LC 223 brass, so I checked and the die (Redding FL sizing die) reduced the neck OD to .241" and after I pressed the carbide expander through it, the diameter was .244". Those are just caliper readings as I didn't bother to get out my mic. So in that case I would need to remove 3 thousandths +/- a thousandth.
I have quite a bit of experience throating revolver cylinders. Normally I just use a throating reamer and a fired casing as a guide on the back side. I needed to enlarge the throats on a Ruger Blackhawk in 30 carbine. No reamer was available, so I used the sandpaper wrapped around a wood dowel (I use a small bit of electrical tape to secure the sandpaper to the dowel) and it worked just fine. I would rather use a reamer but none were available.
Since I expect to wide up making the new die a body die, any lack of concentricity or off axis will not be an issue. But I will try to make it just right for FL sizing without the expander. I can measure neck runout and I will report back. I'm just not sure how hard the die will be. One time I was going to put a witness mark on the top of a Redding FL sizing die, and all it die was blunt the punch. Some hard stuff.
I have a Lee collet die for the 222 Rem Mag. So I already have that covered.
Today I was sizing some LC 223 brass, so I checked and the die (Redding FL sizing die) reduced the neck OD to .241" and after I pressed the carbide expander through it, the diameter was .244". Those are just caliper readings as I didn't bother to get out my mic. So in that case I would need to remove 3 thousandths +/- a thousandth.
I have quite a bit of experience throating revolver cylinders. Normally I just use a throating reamer and a fired casing as a guide on the back side. I needed to enlarge the throats on a Ruger Blackhawk in 30 carbine. No reamer was available, so I used the sandpaper wrapped around a wood dowel (I use a small bit of electrical tape to secure the sandpaper to the dowel) and it worked just fine. I would rather use a reamer but none were available.
Since I expect to wide up making the new die a body die, any lack of concentricity or off axis will not be an issue. But I will try to make it just right for FL sizing without the expander. I can measure neck runout and I will report back. I'm just not sure how hard the die will be. One time I was going to put a witness mark on the top of a Redding FL sizing die, and all it die was blunt the punch. Some hard stuff.
I have been doing that, with my floating pilot reamers, for ~ 14 years.
The problems are:
How are you going to get the barrel concentric with the lathe spindle?
How are you going to get the barrel bore parallel with the lathe spindle?
How do you keep the rear of the reamer from wandering off center?
There are plenty of guys arguing about how to do that, but my shpeal is that it does not matter much. Better off with a chamber that is bent than ammo that is bent.
I can shoot sub moa with a chamber that finishes 0.006" off center at the rear.
Those old gunsmiths that wasted their lives dialing in barrels to 0.0001" should have put their effort in to sizer dies.
With the 1941 Southbend I use,the last .0001 doesn't matter so much,maybe.
But,I have a 4 screw spider on the back end of the spindle,and a 4 jaw chuck.
I also have two indicators available,and sets of pin gages.
I don't "spend my life" to get Total Indicated Runout inside .0005 both ends
I'd guess about 15 minutes or so.
I bought a floating reamer driver from Elliot Reamers...simple,but it works.
But a commercial die is not a barrel.A die will be harder than woodpecker lips,and you'll just mess up a reamer.
OP,you might go to MSC's site,and search for "brass lap" or "barrel lap"
The "barrel" part is not about rifle barrels.Its about barrel staves,like whiskey barrels.
They have a steel mandrel,with a piece of brass tube the appropriate size attached.The brass is split,like a collet,and there is an adjusting screw the makes the lap expand.
You charge the brass lap with abrasive.Diamond,silicon carbide,or aluminum oxide.
Diamond is nice but expensive.Silicon carbide cuts aggressively but may not leave as fine a finish.Aluminum oxide is probably the stuff I'd use.
Some kerosene or diesel for supplemental lube.
I'd probably set it up in a Bridgeport in a vee block instead of a lathe,easier to stroke in and out with the spindle.
Those laps are not to spendy and work pretty good for .001 or .002.
They would do throats on a wheelgun OK.too.
I know this will bring a gasp of disapproval,but I have patiently cut a chamber with a barrel vertical in a vise,holding the reamer with a tap wrench,turning it by hand.Let the pilot follow the bore,the trick is to apply rotational force without applying side force.If you can hand tap through 1/4in of stainless with a 2-56 tap,you can do that.Keep turning clockwise to back out the reamer.Tap handle has to be tight My results were fine.
But,I have a 4 screw spider on the back end of the spindle,and a 4 jaw chuck.
I also have two indicators available,and sets of pin gages.
I don't "spend my life" to get Total Indicated Runout inside .0005 both ends
I'd guess about 15 minutes or so.
I bought a floating reamer driver from Elliot Reamers...simple,but it works.
But a commercial die is not a barrel.A die will be harder than woodpecker lips,and you'll just mess up a reamer.
OP,you might go to MSC's site,and search for "brass lap" or "barrel lap"
The "barrel" part is not about rifle barrels.Its about barrel staves,like whiskey barrels.
They have a steel mandrel,with a piece of brass tube the appropriate size attached.The brass is split,like a collet,and there is an adjusting screw the makes the lap expand.
You charge the brass lap with abrasive.Diamond,silicon carbide,or aluminum oxide.
Diamond is nice but expensive.Silicon carbide cuts aggressively but may not leave as fine a finish.Aluminum oxide is probably the stuff I'd use.
Some kerosene or diesel for supplemental lube.
I'd probably set it up in a Bridgeport in a vee block instead of a lathe,easier to stroke in and out with the spindle.
Those laps are not to spendy and work pretty good for .001 or .002.
They would do throats on a wheelgun OK.too.
I know this will bring a gasp of disapproval,but I have patiently cut a chamber with a barrel vertical in a vise,holding the reamer with a tap wrench,turning it by hand.Let the pilot follow the bore,the trick is to apply rotational force without applying side force.If you can hand tap through 1/4in of stainless with a 2-56 tap,you can do that.Keep turning clockwise to back out the reamer.Tap handle has to be tight My results were fine.
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Clark, remember that all ammo's bent in the chamber when it fires. Except for those whose cases' diameters are exactly that of the chamber at all points around the case. The other 99.999% have their back end off center from that external force applied to them; it's called a spring loaded extractor.
All the cases are perfectly centered in the chamber at peak pressure when the bullets several inches down the barrel, but then it doesn't matter. The bullet's already taken a set to the bore.
All the cases are perfectly centered in the chamber at peak pressure when the bullets several inches down the barrel, but then it doesn't matter. The bullet's already taken a set to the bore.