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Old February 16, 2012, 08:35 PM   #26
totaldla
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Quote:
Originally Posted by dacaur

The cast iron press is in no way, shape, or form weaker than aluminum. Cast iron will ALWAYS win out in durability....
Look up the material properties and then comment.

The benefit of cast iron is that you can get it manufactured in China with less screwups.
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Old February 16, 2012, 10:18 PM   #27
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Not so sure

Quote:
Originally Posted by totaldla
The benefit of cast iron is that you can get it manufactured in China with less screwups.
RCBS tried that for a while, then went back to U.S. made press frames.

Quote:
Originally Posted by totaldla
The cast iron press is in no way, shape, or form weaker than aluminum. Cast iron will ALWAYS win out in durability....

Look up the material properties and then comment.
Aluminum is lighter than Cast Iron or steel by a factor of about 2.8 so is much lighter for its strength. The modulus of elasticity:
aluminum - 69 million pounds per square inch
Gray cast Iron 130
Wrought Iron or Steel 200

So, for the size, iron and steel are two to three times as strong as aluminum. However, Aluminum is lighter than steel by a factor of about 2.8. So Aluminum can be actually stronger (by weight) than steel.

I haven't found a handy source to compare the abrasion resistance of the three metals under discussion, but I thinkg everyone knows that cast iron is more abrasion resistant than aluminum , so will last much longer.

If anyone has comparative abrasion data, please contribute.

How do you define strength?

For my own self, I prefer my metals ferrous, whether cast or forged, but do recognize that aluminum does not rust, is cheaper and lighter. So I believe either choice is valid, so choose your poison and go in peace.

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Old February 17, 2012, 10:50 PM   #28
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Quote:
Look up the material properties and then comment.
Other than abrasion resistance, where cast iron wins vs aluminum, The really important quality here is fatigue life. Steel and cast iron have a much longer fatigue life than aluminum. What that means is that with steel and cast iron, as long as you dont exceed its structural strength, cast iron or steel will last somewhere in the order of hundreds of times longer than aluminum. (Not hundreds as in 100-500 more cycles, if aluminum lasts 5x10 to the seventh power cycles, steel or cast iron will last 100-500x10 to the seventh power cycles) Take 3 bars, one steel, one cast iron, and one aluminum, and put bending pressure on them equal to half their strength, then release, then repeat that over and over. Steel and cast iron will go on MUCH longer than aluminum millions of cycles more, despite the fact that you are not even really straining it. Aluminum has the lowest fatigue life of any metal out there. This is why airliners, which are mostly aluminum, have a service life, that once it passes a certain number of takeoff/landing cycles, its scrap, because the aluminum skin can only handle so many pressure cycles from gaining and losing altitude.

I'm not saying you will ever break an aluminum press, just that the aluminum one WILL break before a cast iron one, barring abuse.

Chances are the ram going up and down will wear out the aluminum before it ever reaches its fatigue limit, long before the ram wears out the cast iron unit...
Show me an aluminum instrument that has any chance of lasting generations like many cast iron ones HAVE.
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Old February 18, 2012, 12:42 AM   #29
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This is my Lee Deluxe set up. As I mentioned I have it such that the primers come out the bottom into a garbage bin. It may not be as good as the Classic, but if it lasts be a few solid years while I cut my teeth at reloading I'll be happy!
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Old February 18, 2012, 01:00 AM   #30
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ah... my problem is that my primers dont go into the holes in the press base... If I keep the primer arm in they do, but in decapping many at a time, it gets gritty and starts to stick then flies out onto the floor (the primer arm).... I guess going slow would help, but me no likey go slow!
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Old February 18, 2012, 01:05 AM   #31
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A bunch of those deluxe turrets have been in operation for quite a few years, meatsaw.

I doubt you'll have to worry about wearing it out unless you willfully abuse it.
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Old February 18, 2012, 01:14 AM   #32
totaldla
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Quote:
Originally Posted by dacaur

Other than abrasion resistance, where cast iron wins vs aluminum, The really important quality here is fatigue life. Steel and cast iron have a much longer fatigue life than aluminum. What that means is that with steel and cast iron, as long as you dont exceed its structural strength, cast iron or steel will last somewhere in the order of hundreds of times longer than aluminum. (Not hundreds as in 100-500 more cycles, if aluminum lasts 5x10 to the seventh power cycles, steel or cast iron will last 100-500x10 to the seventh power cycles) Take 3 bars, one steel, one cast iron, and one aluminum, and put bending pressure on them equal to half their strength, then release, then repeat that over and over. Steel and cast iron will go on MUCH longer than aluminum millions of cycles more, despite the fact that you are not even really straining it. Aluminum has the lowest fatigue life of any metal out there. This is why airliners, which are mostly aluminum, have a service life, that once it passes a certain number of takeoff/landing cycles, its scrap, because the aluminum skin can only handle so many pressure cycles from gaining and losing altitude.

I'm not saying you will ever break an aluminum press, just that the aluminum one WILL break before a cast iron one, barring abuse.

Chances are the ram going up and down will wear out the aluminum before it ever reaches its fatigue limit, long before the ram wears out the cast iron unit...
Show me an aluminum instrument that has any chance of lasting generations like many cast iron ones HAVE.
Wow! Good thing that high-end presses don't use aluminum
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Old February 18, 2012, 01:23 AM   #33
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Quote:
Wow! Good thing that high-end presses don't use aluminum
Again, I'm not saying aluminum isnt a suitable material for a press, read the second to last paragraph you quoted, I was simply replying to the guy that thinks aluminum is stronger than cast iron....
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Old February 18, 2012, 01:33 AM   #34
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Quote:
ah... my problem is that my primers dont go into the holes in the press base... If I keep the primer arm in they do, but in decapping many at a time, it gets gritty and starts to stick then flies out onto the floor (the primer arm).... I guess going slow would help, but me no likey go slow!
I'm a slow n steady kind of guy. As such I am getting about 90% of the primers to fall into the base (and therefore into the bin) -- the other 10% wind up right next to the press which is easy to sweep into the bin. An effective and cheap solution would be to use cardboard and block off the back and far side. This would force them to fall back into the base. I have lots of cardboard -- I will try this out. I have about 150 rounds to de-prime. I will try it out and purposely speed up and see if its effective.

Quote:
A bunch of those deluxe turrets have been in operation for quite a few years, meatsaw.

I doubt you'll have to worry about wearing it out unless you willfully abuse it.
This is too much fun to be worried over.
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Old February 18, 2012, 08:00 AM   #35
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Well,I got the press,4 hole and this one looks to be made of cast iron..I do know it is heavyer than the other one is..
And I could give a rats ass what it is made of as long as it works..And works like it is suppose to..Thanks for all of your infomation filled replies...

GOD BLESS AMERICA.....John
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Old February 18, 2012, 11:44 AM   #36
totaldla
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Quote:
Originally Posted by dacaur

Again, I'm not saying aluminum isnt a suitable material for a press, read the second to last paragraph you quoted, I was simply replying to the guy that thinks aluminum is stronger than cast iron....
But cast aluminum is stronger than cast iron. Not sure why that is so hard to understand. Pound for pound, cast aluminum is stronger than cast iron. The only reason why Lee is using cast iron now is that they can get it cheaper and with less defects from China and they can get away with steel on steel wear points and not need bushings. It is a cost issue to Lee. This design approach is why Lee can sell a best in class Turret press for less than an RCBS Rockchucker.
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Old February 18, 2012, 01:00 PM   #37
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Evidence?

Quote:
Originally Posted by totaldla
The only reason why Lee is using cast iron now is that they can get it cheaper and with less defects from China ... (edited for brevity)
RCBS used to get press blanks from China, but only did this for a short time before returning to American iron. Do you have any more detailed information? Is it ingots, is it finished frames? Is it second-hand information?

Would you bet your Diamondback against my Judge on the accuracy of your statement?

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Old February 18, 2012, 03:25 PM   #38
dacaur
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Quote:
Pound for pound, cast aluminum is stronger than cast iron.
LOL, ok I see the problem here. "pound for pound"? Yea, that would be stronger, but that would also defeat the purpose of using aluminum, since it would have to be so much bigger. No MFG would make something out of aluminum and make it the same weight as they would if it were cast iron. The whole reason to use aluminum is to make it "strong enough" while still being light.
Nobody uses aluminum when ultimate strength is required, because "inch for inch" its hard to find a weaker metal.
A 1"x2" bar of cast iron 12 inches long would weigh 6 1/4 pounds vs aluminum the same size would weigh 2 1/3 lbs, but to get the aluminum bar to weigh the same as that 1"x2"x12" bar of cast iron, the aluminum bar would need to be 32" long... thats nearly 3 feet of aluminum to make the same "pound for pound" weight of one foot of cast iron....

The fact of the matter is we are not talking about the "pound for pound" strength of cast iron vs aluminum, we are talking about the strenght of lees' cast aluminum press vs their cast iron press, and the cast iron press is stronger in every way. Your original statment
Quote:
The cast iron [press] is weaker than aluminium.
is wrong, get over it.

Also
Quote:
This design approach is why Lee can sell a best in class Turret press for less than an RCBS Rockchucker.
The cast iron lee classic is only a few dollars more than the cast aluminum press, and i can guarante those dollars dont come from the aluminum vs cast iron base. IT comes from a whole lot more steel in the linkages, the double diameter hollow ram, and more steel in the thicker and longer uprights.

The classic press has a cast iron base because it needs the EXTRA STRENGTH of cast iron to handle the additional leverage required for the bigger cartridges the classic can handle.

Last edited by dacaur; February 18, 2012 at 03:31 PM.
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Old February 18, 2012, 04:29 PM   #39
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In terms of weight aluminum wins. "Pound for pound" is a comparison of strength per weight. In terms of the base of the press weight really doesn't matter. Its bolted to a bench. So "pound for pound" strength doesn't really mean much. What does mean a lot is strength per volume. If you cast a press and are restricted to 4 cubic inches then the 4 cubic inches of iron is going to be a lot stronger than 4 cubic inches of aluminum.

But in the end what difference does it make to you? I personally will only be using my deluxe kit for 40, 45, and 223. Aluminum will work fine in its intended use.

decaur -- good post!
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Old February 18, 2012, 04:48 PM   #40
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Grey cast iron has a tensile strength of about 50,000 psi. That would be the most likely type used for a press.

Depending on the exact type of aluminum and how it is hardened or annealed, varies widely.

My guess is that press bases are made of 6061-0 or 6061-T4. 6061-T6 is a lot more expensive, but a lot stronger (comparable to grey cast iron).

O has a fairly low tensile strength, T4 more so, at about 18,000 psi and 30,000 psi respectively.

Not sure how that would translate into a press base, but I do know that over time the aluminum base of my Lee Turret (the original 3 hole design) began to flex and crack and is no long suitable for use as a press.

My RCBS Rockchucker, though, is close to, if not over 50, years old, and has had a similar number of rounds run through it.

Its base is still the same as it always was.
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Old February 18, 2012, 10:13 PM   #41
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The whole point of online forums is the exchange of information. If someone is going around giving out wrong information, they need to be advised and the correct info posted.
Sure it would save a whole lot of forum space to just "let it go". I know I'm right an thats all that matters, right? Wrong.
The problem with just letting it go is that then you have X number of people who see the incorrect info, see that no one disputed it, and now thats "good" info in their mind, that they are going to one day pass on to someone else, and so on and so forth. It becomes a vicious cycle and has got to be stopped whenever its seen, even though it does at times detract from a thread, its a necessary part of online forums.....
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Old February 19, 2012, 12:30 AM   #42
totaldla
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Quote:
Originally Posted by Mike Irwin

Grey cast iron has a tensile strength of about 50,000 psi. That would be the most likely type used for a press.
Actually, grey cast iron starts at 20Kpsi for ASTM 20. And it is very cheap, and easy to machine. I would think this is what would be used mainly because it easy to work with.

Quote:
Originally Posted by Mike Irwin
Depending on the exact type of aluminum and how it is hardened or annealed, varies widely.
Very true. 380 Aluminum has 46Kpsi tensile strength and is common in die casting. Lee uses this for their Challenger single-stage press.

I was just staring at my Dillon (aluminum) and my LCT (cast iron) and I believe that the design of the LCT really doesn't put much stress on the base.

Last edited by totaldla; February 19, 2012 at 12:43 AM.
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Old February 19, 2012, 12:44 AM   #43
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You're right, I was thinking A48, which is the kind often used for machine tool bases, lathe beds, and the like.
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