Everything can flex, you can measure it or even run an FEA on it and see where/why.
That said there have been billions of rounds loaded on machines that flex more than the most ridged one ever made.
As far as material goes there are lots of aluminum presses for benchrest shooters to choose from and they seem to get satisfactory results. If you’ve ever shot a benchrest match, you’ve been beat by ammunition loaded on an aluminum framed press.
As we get into the minutia of press-springing, I wonder what the readings off a turret press would be?
That little Grizzly press has been around for quite a while & that is a good price on it.
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I form too many cases to fool with a "C" press. Sizing brass they are probably fine but I know I've put a lot more stress on presses when forming some cases than I ever did just sizing any brass.
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NO! Just would like him to share his findings. jmorris stated he has tested his press. I reload 90% of my ammo on a Co-Ax and due to the design, I believe there would be some vertical die movement, but FWIW I've been able to hold some lineal dimensions to .001" variation. I also have a "C" press that I sometimes use...
If I'm in doubt, I'll just say so...
Last edited by mdi; 11-28-2018 at 03:31 PM.
My Anchor is holding fast!
I would have to go back and look at my notes for deflection measurements. I never finished this project of mine (to test many different presses) but I did get far enough to have some data.
https://www.thehighroad.org/index.ph...-exert.826834/
From what I did post in that thread the mechanical advantage can be significant, like less than 22lbs on the handle is more than 1000lbs of force .100” from the top of the stroke.
The late Richard Lee was an engineer who knew the strengths and weaknesses of various metals and alloys quite well. The aircraft aluminum alloys he chose to design his presses around have tremendous tensile strength, more than enough for common reloading chores.
Lee wanted to allow users to adjust the lever for their own needs so he made the toggle block in two parts that allowed angular adjustment.
Every photo I've ever seen or heard about a "broken" Lee alum alloy press was the two part toggle block cracking and that because the user failed to properly keep the steel bolt holding the two blocks together. That's user neglect and it's hardly the presses' fault!
Thick, heavy chunks of expensive steel and iron are obviously "stronger" than the lighter size chunks of the hard cast alum alloy Lee uses. But, Lee makes their presses more than strong enough to handle the expected work of the vast percentage of reloaders and spending more than they need to do the job seems foolish to me. And, as someone mentioned above, Dillon (and Hornady) and their users obviously agree. (RCBS has made some alum alloy presses that broke if over loaded too!)
So far as broken presses go, some clutzy people can destroy an anvil with a spoon but who blames the anvil? I've seen two and heard of more of the highly vaunted Big Green RC's like mine with snapped top bars, probably due to efforts to "cam over" way more than the hefty cast iron could take! Just meaning that when something mechanical is engineered to be fool proof there will always be a random few more talented fools who can succeed.
Limited life stress cycles for alum alloys may be true but that doesn't seem to hurt automobile, motorcycles and outboard engine blocks and pistons or actions for many rifles, shotguns and pistols, etc.
I've long reformed military .30-06 to various other cases, down as far as .22-250, and (not being a fool) I do that work on my RC II. But, be honest, what percentage of reloaders will ever do that?
I have five presses, mostly iron, but when a noob asks "What loading tools should I get?" I try to use my experience to suggest tools based on HIS likely needs, not mine. So, I often point them to Lee's tools. I know that IF he later outgrows the Lee tools, and some do, he should then have the experience to wisely chose whatever he needs or wants to add to his bench without asking me .... or anyone else. And I've NEVER heard of any avid reloader saying "I wish I didn't have so many presses and dies and scales and powder measures", etc.
Just to state what should be obvious to truly experienced reloaders, Big Green's big presses are good but they are NOT in any way superior to other brands of presses of similar design. In fact, it's my judgement that a young friend's Lee Classic Cast (iron) is at least as strong as my RC and he has some much better user features such as a fully adjustable lever, a spent primer catcher that actually works, and a more massive and wear resistant ram. If I ever have to replace my 25 year old green press my next one will be as red as his!
Last edited by 1hole; 11-29-2018 at 05:10 PM.
Aluminum costs more than steel or cast iron per pound. One good reason to use it though is tool life and the speed at which you can machine it.Thick, heavy chunks of expensive steel and iron are obviously "stronger" than the lighter size chunks of the hard cast alum alloy Lee uses.
Okay Now Ill throw in another area that may be related to stretch. That nice shiny set of 7/8 14 dies in a belted magnum or large heavy case size ( Some of these new cases are pretty large now) when sizing cases. How much to they swell in dia due to the radial force of squeezing the case down? All materials under force will expand swell or stretch.
I knew I posted a video, just didn’t remember what account I used, here you go.
I watched the video, but I'm not sure what I saw. Did the indicator move? I couldn't tell and on my computer the sound was a bit garbled...
No I am not arguing the point. I'm looking for answers. I set up a similar dial indicator/press test many years ago (I like to confirm stuff I read on line) but as far as I can remember, my test didn't work out well (setting up on an alum. press with limited indicator accessories). This is one of those often repeated (parroted) but untried posted "facts" I see, and a much touted reason for condemning some presses, without actually confirming.
BTW the pressure test was very informative, thnx...
My Anchor is holding fast!
A crummy video for sure but if you pause it at 9 seconds, you can see it’s on zero and at 23 seconds it’s off zero.
I think we are one in the same that’s why I started the testing was to gather some facts. Life has just gotten in the way of finishing the work.
IMO, that YouTube clip is so poorly done that it's meaningless.
Several method-type things affect press spring tests while resizing, including these:
1. Hardness of the metal alloy and degree of case reduction, especially near the head
2. How far down the sizer is adjusted (headspace)
3. External size of the individual fired case(s) compared to the internal size of the individual FL die's chamber
4. Case lube type, and especially it's proper application near the web.
Obtaining accurate press spring measurement depends on a good dial indicator, ideally one reading in tenths of a thousanth inch (.0001") AND set so the test plunger is in vertical alignment with the FL die. The dial indicator/mount MUST be firmly anchored directly to, or firmly with, the press' body.
When performing a reloading press "springing during resizing test" each case used is a "once and done" item because once a case has been resized, the hard (springy) part is done. Ideally, all tested cases should be of the same maker and lot number AND have been fired the same number of times in the same chamber with the same load.
When testing to compare spring in two or more presses it is imperative that the same cases, FL die (adjusted to achieve the same shoulder set back) and case lube is used.
Unless the press is bolted tightly down on a cast bed plate and the dial indicator is located on the plate , the frame stretch can be measured.
I do mean heavy cast iron plate 4 or more inches thick.
I think there are presses that do not have any stretch, such as the Redding Ultra Mag where the linkage arms are
attached at the head of the press.
I have the Pacific Super Mag press, three rams - no flex - swage bullets - form case's no problem.
Worth every dollar I've spent on it.
Last edited by jaguarxk120; 11-29-2018 at 06:19 PM.
It does not look to be designed to be especially strong. I would not trust it when reloading Big-Boy cartridges.
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It’s hard for me to disagree with that, most important is that you agree that “spring” exists, if the video had more information and I had captured it better, I would have posted it on one of my other accounts and started a thread here. It was just evidence that it does exist, to someone meaningless to this conversation, even with crude measuring instruments.IMO, that YouTube clip is so poorly done that it's meaningless.
Several method-type things affect press spring tests while resizing
You get something more precise and you can see even the strongest of devices flex.
In any case if you can measure deflection with a .001” indicator (even in a crummy video) you don’t need one that has a .00002” resolution to prove that something is moving.
I would be interested in new angles to approach the problem. Some presses can be difficult to measure. Like the Co-ax, lots of stuff happening on the press that doesn’t effect runout, concentricity, OAL and such in the finished product but measurements are not as easily repeatable as most presses on the market.
I guess that’s the hard part, you don’t know what you don’t know, until you learn it.
Last edited by jmorris; 11-29-2018 at 10:51 PM.
You get something more precise and you can see even the strongest of devices flex. I would LOVE to own that 20 micro-inch indicator!
You're absolutely right, everything flexs to some degree. Part of what I've meant here is, "Yes, there is always some press springing under load but how much does a tiny amount of press spring matter to us?"
IMHO, no American made press flexs enough to bother reloaders. I doubt that even people who get consistent groups of < 1/4 minute accuracy will ever see any (proveable) degregradition of their accuracy due to flex from any normal press.
Truth is, case brass is an imprecise metal alloy and brass deforms quite easily and cases aren't made with rocket precision so our FL sized cases seldom spring back exactly the same. All this means that normal case spring back effects usually exceed the hard to measure differences in press springing.
Thus, agonizing to produce FL sized cases constant within 1/4 of a gnat's **** and/or stoutly defending a favorite press may be fun for some ... but it's virtually futile.
Press frame springing/flex during the pressure of bullet seating is so slight I believe we can safely think of any common press effectively as being totally rigid for that task!
I guess that depends on the “us”. I have loaded rounds on the above Lee that are 3/8 MOA so the fact that it flexes doesn’t bother me and I have won lots of matches with ammunition loaded with numerous aluminum presses."Yes, there is always some press springing under load but how much does a tiny amount of press spring matter to us?"
I was just answering the statement,
And the answer is yes, one can.I seriously doubt if the "flex" would be measurable (someone could place a dial indicator on the top of the frame and size a large case and measure just how much, if any a press will flex)...
Last edited by jmorris; 11-30-2018 at 10:01 PM.
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