Hydraulic pressure on the Star can break boolits!

[MBTcustom]

You guys gotta see this. I really don't have a problem, its just kewl and I thought I would share:
Pushing the boolits through the Star, and "POP!" the tip falls out, and the base follows when the second boolit is pushed in. WOW, huh?
This happened a couple two or three times, so I thought "Gee, maybe I should back off on the lube pressure?" LOL!
106075

[Sgtonory]

Wow. That may be a little to much pressure :)

[6bg6ga]

Ok, I'll bite...how much pressure?

[gtgeorge]

Was that a bullet defect? I have seen that when molds were opened too quick and hot as well as the bullet cocking as it fell. Never saw it happen on a good bullet.

[HATCH]

Bad boolit

[dragon813gt]

Is that a Mihec 30 Sil bullet? If so it wasn't from the hydraulic pressure. It was from the bullet being bent. I got rid of that mold because it didn't like releasing bullets and to many of them were damaged(bent) when they did release. I had the same type of breakage in a RCBS LAM.

[MBTcustom]

This is the Mi-Heck 30 Sil, but it's one of the remakes.
The boolits drop from the mold perfectly, and I have never had any problems with "bent boolits".
Besides, these had already gone through a rigorous inspection, and anything like that would have been thrown out.
These boolits were cast from 50/50 WW/Pure water dropped. The lube groove on the 30SIL is very deep rendering a thin little shank that connects the top of the boolit to the bottom of the boolit.
I know it was hydraulic pressure that cracked these, because of the way it did it. If I just pushed them through, but didn't follow through with the squirt at the bottom of the stroke then they would run on through with lube streaks ahead of the groove etc etc, but if I pushed them in and bottomed the handle, there was this "Pop!" sound and the nose of the boolit would fall out of the die followed by a gob of lube.
I had just emptied the press of 2700+ and filled it with LARS 2500+ but I didn't give the press time to cool, and I was running the air pressure at the same 50psi that I was using for 2700+.
I corrected this problem by letting the press cool down for a while, and dumping the pressure to about 20 psi.
I sized about 200 boolits then without a problem and I was going the full stroke.

Just thought it was interesting is all.

[6bg6ga]

I'm going to go with the bad bullet idea. If you stop and calculate the possible pressure give the diameter and stroke of the pump and the pressure on the lube in the tube I sincerely doubt it broke the bullet. I am however not an engineer and I would assume that one will pop up out of the brush at any minute with an answer.

As a note... I have run in excess of 100 psi with the Mark VI and with my Star without breaking a thing.

[dragon813gt]

I wasn't aware he made new blocks. I gave up and sold it off. Figured since I have the hollowpoint version it wasn't worth the trouble. I find it amusing that your bullet broke just like mine did.

[jmorris]

I'm going to go with the bad bullet idea. If you stop and calculate the possible pressure give the diameter and stroke of the pump and the pressure on the lube in the tube I sincerely doubt it broke the bullet. I am however not an engineer and I would assume that one will pop up out of the brush at any minute with an answer.

You already have the PSI he used, 50 PSI. Now all you need is to know he area that the force is acting on. If its 1 sq/in you have 50 lbs of force, 2 sq/in 100 lbs, etc.

[MBTcustom]

You already have the PSI he used, 50 PSI. Now all you need is to know he area that the force is acting on. If its 1 sq/in you have 50 lbs of force, 2 sq/in 100 lbs, etc.

Actually, 50psi is only the pressure that is placed on the lube column.
In a Star, the pressure from above is only there to feed lube to the piston that is actuated at the bottom of the stroke and the pressure that piston is able to create far outstretches the pressure on the column. Ordinarily, this piston just gives a small shot of lube (about enough to feed you lube grooves) and it's being fed lube that is just warm enough to be plastic, so it's doesn't really get full value for it's stroke, but it's more than enough to squirt lube in the grooves (through .040 diameter holes BTW. A Lyman uses 1/8" holes because it depends on the column pressure alone to feed the lube grooves.).
In my case, I had just melted all the lube out of the press with a torch, so it was cooking pretty hot when I slid the new lube in there. Also, I was running pretty high pressure on account that I had turned it up to squirt all the old lube out of the press.
This created a situation where the piston was being fed lube that wasn't just plastic, it was completely liquid. This allowed the piston to give full value for it's stroke and create a lot more pressure than usual. Coupled with the fact that I am using a boolit that has the most fragile midsection of any that I have ever used, and the boolits are able to pop apart.

I broke the first boolit when I pushed the handle all the way down. I knew what had happened by the way it felt, so I pushed 5 more through but I didn't push the handle all the way down. Just gave the piston enough of a bump to fill the groove. So then I tried it again, pushed the handle all the way down on the next two, and it broke both of them in two.
No big deal, I chuckled a little and turned the heat and pressure down so that the piston would get fed it's standard diet of slightly softened lube. Once the temperature and column pressure was back at a reasonable level, I sized and lubed a whole pile of boolits, full stroke, and none of them broke.

It was hydraulic pressure that broke them, and any of you would agree with me had you been there.
I just thought it was interesting that's all. I really don't know of another boolit design that is fragile enough to be susceptible to this phenomenon.

[gtgeorge]

In your case I am sure you know what caused yours to break. I have however seen them blow apart with a snap on the 125gr Mihec 9mm mold when I was creating some weakness from bullet angling out of the mold and not solid enough before they came out. Another case of a small column holding the bullet as well with the deep lube groove. In my case it was random bullets in the batch and I corrected my casting technique after that.

Since you could do it repeatable at the end of the stroke I am sure that did do it from your description. If I overheat the lube on mine to be too liquidity I have no pressure other than coming from the air cylinder. I wonder if I need a new plunger and brass bushing?

[freebullet]

You did a fine job on that boolit.

A liberal smiles every time a bullet is destroyed without firing.

I try not to let that happen much.

[6bg6ga]

You already have the PSI he used, 50 PSI. Now all you need is to know he area that the force is acting on. If its 1 sq/in you have 50 lbs of force, 2 sq/in 100 lbs, etc.

I kinda realize the pressure involved. That is why I don't buy the pressure breaking the bullet idea.

[jmorris]

I kinda realize the pressure involved. That is why I don't buy the pressure breaking the bullet idea.

It sounds like there is more going on than just air PSI and bore size, from his reply. I also don't have one of the machines to actually know what we are talking about.

I can tell you that I have pneumatic over hydraulic devices that can convert 90 psi to around 3000 psi. So, not knowing more than I do I cannot disbelieve it.

[MBTcustom]

It's true that 50 PSI is not enough to break these boolits. But lube isn't fed directly to the die by that 50PSI source. The 50 PSI only supplies the piston with lube. The piston is what squirts the lube through the .040 holes and into the lube grooves, and it generates extremely high PSI. Ordinarily the lube is so stiff that it requires all that pressure to push it gently into the lube grooves, but if you thin out the lube it robs less pressure from the piston and is transferred directly to the lube groove. In this case, that was enough to break the boolits in two if I gave it the full stroke.
It was consistent, repeatable, and preventable.
Once the lube temperature was reduced, the lube thickened up and required more pressure to move through the tiny holes in the die, thus protecting the boolit from the piston as well it should.

[6bg6ga]

As one that had spent 20 years in a factory working on hydraulic cylinders and machines I fully realize the pressures involved and the possibility to obtain high pressures from a little cylinder. I still support my idea the breakage was probably more likely caused by a bullet defect that it was high pressure. Believe what you feel comfortable with.

Still waiting for someone to install a pressure gauge in the clean out plug.:kidding:

[6bg6ga]

It sounds like there is more going on than just air PSI and bore size, from his reply. I also don't have one of the machines to actually know what we are talking about.

I can tell you that I have pneumatic over hydraulic devices that can convert 90 psi to around 3000 psi. So, not knowing more than I do I cannot disbelieve it.

So not knowing more than I do cannot disbelieve it? Cocky attitude. Until someone can provide an ACTUAL pressure in this instance all ideas are just that.

[gtgeorge]

Well I will see if I can fit a pressure gauge in the tiny port on the side of mine to see but I am pretty sure the pressure will be quite low and even lower with thinned out lube since the piston and bushing are not a perfect fit (at least not on mine). That is if inquiring minds just have to know LOL.

I have thought about machining a groove in the piston and installing a Teflon ring from a transmission to see if that improved lube performance since my Star is picky in so much as it does not always fill the grove on every bullet that passes through her dies.

I for one can believe something that doesn't make sense though if it is repeatable more than a few times either way. I think goodsteel is an experienced caster that could make a good judgement call on the quality of his cast soldiers. Which brings me to ask if there is a better seal in the later Star sizers or Magma sizers than the semi loose fit of my old San Diego Star?

[6bg6ga]

I'm sure that goodsteel is a good caster but even the best casters can run into trouble with the right mold and circumstances. Speculation is nice but it would be much more helpful to to back up an idea with proof. If say the Star/Magma is capable of x number psi then lets get the facts down and documented then its fact. This fact will then serve to help every caster that is using the Star/Magma.

[jmorris]

So not knowing more than I do cannot disbelieve it? Cocky attitude.
I didn't intend for it to come off as "cocky", just didn't have enough information to disprove it. I know I could develop enough pressure to do that kind of damage, so how could I disbelieve his machine could, without more knowing more about it?

[MBTcustom]

Please tell me nobody is going to start slinging mud over the quality of my boolits (or lack thereof).
I only posted it because I thought you fellers would get a chuckle out of it. It was a lighthearted post.
If you need to believe that my boolits were damaged and I (who have been building, maintaining, designing, and creating machinery for the last 15 years, and have been casting even longer) am completely cross-eyed and mistaken about what my equipment is doing, then please be happy in that belief (you are not the first nor will you be the last).
I'm not torn up about it.
I do scratch my head though, because if my boolits were damaged, I had the magic touch to precisely choose the five bad ones right out of the pile, break them, then proceed to size and lube the remaining 300 good ones.
That seems like a long shot to me, but I'd rather be lucky than good any day of the week.
Don't sweat it fellers.

[dragon813gt]

I suggest you pick up a couple Powerball tickets because you seem to be lucky ;)

I don't understand how this thread got to the point it has.

[MBTcustom]

It got here because people have an opinion, as well they should. There's nothing wrong with that.
I just wish you guys were closer, so you could come over and we would investigate this further. If indecision remains, then there's always beer and cigars! LOL!

[Springfield]

I have that happen sometimes with some of my Big Lube bullets. Mostly it happens when I was running too hot, and on some of the bullets, especially the 45-70 ones, you can see a crack in the corner of the lube groove. So I also believe these bullets were cast just a bit hot. It almost never happens when I am casting properly, just when I get going too fast and run hot and get frosted bullets. It has happened too often to just be a coincidence. I can't prove it, of course, just been my experience. For what it is worth I generally run 100 psi on the air lube feed.

[6bg6ga]

So far you have a theory and one that has no proof behind it. You have no pressure reading, nothing to prove that there was enough pressure to actually fracture the bullet. Instead of the typical "walking on the moon" comments how about a pressure reading? In my primitive mind gentlemen there are two possibles here. 1.) There was enough pressure to simply shear the bullet in two. 2.) There is a possibility the bullet looked good and had an internal flaw and broke.

Possibilites here to consider... The mold has a reputation for being flawed/ producing flawed bullets. Goodsteels sizer actually has a tighter fitting piston than most sizers out there and is capable of producing very high pressures.

If indeed goodsteels machine is capable of pressures high enough to fracture bullets then there is a possibility that any Star/Magma when the pressure is turned up should be able to fracture ANY bullet run thru it. Can these results be repeated with a different bullet?

[MBTcustom]

So far you have a theory and one that has no proof behind it. You have no pressure reading, nothing to prove that there was enough pressure to actually fracture the bullet. Instead of the typical "walking on the moon" comments how about a pressure reading? In my primitive mind gentlemen there are two possibles here. 1.) There was enough pressure to simply shear the bullet in two. 2.) There is a possibility the bullet looked good and had an internal flaw and broke.

Possibilites here to consider... The mold has a reputation for being flawed/ producing flawed bullets. Goodsteels sizer actually has a tighter fitting piston than most sizers out there and is capable of producing very high pressures.

If indeed goodsteels machine is capable of pressures high enough to fracture bullets then there is a possibility that any Star/Magma when the pressure is turned up should be able to fracture ANY bullet run thru it. Can these results be repeated with a different bullet?

OK, here are a few facts that might have helped create a perfect storm here.
1. The Mi-Heck 30 SIL is a very week design with a very thin little shank at the bottom of the single lube groove. (yes it is true that it is difficult to get it to fill out properly, but I have already encountered this, adjusted my casting style. These boolits were cast at a very specific rhythm , sorted by visual inspection (especially in the lube groove and the edges on either side of it), sorted by weight, and were finally ready for the sizer. You can read all about this in my thread "how consistent are you really?")

2. My Star is an old Sante Fe model, and it was absolutely unused when a got it running a few months ago. At this point, it's had less than 2000 rounds pushed through it.

3. The lube was over heated when this happened which made it very thin. (why do they use oil for hydraulics and not wax?)

I think the inherent weakness of the design, the newness of the machine, and the fluidity of the lube contributed to making this perfect storm.

However, I was just giving my opinion for the enjoyment/amusement of others. I was not prepared to have to back up my thoughts with proof. That said, I love science, and I'm willing to run a test if you fellers can help me a little bit.
It so happens that I have some blank Star dies here that I could use to plug off the main hole, thereby forcing the lube out of the die lock screw hole. I think this would be as close as we could get to a true idea of what is possible, because it is directly in line with the die (exactly the same distance from the piston) which I'm sure you all agree is rather important for measuring hydraulic pressure.
Now, that lock screw hole is 1/4-20 threads. Does anybody have a pressure gauge they could loan me that would fit in that thread? I've got bupkis for hydraulic pressure gauges around here, and I would think they might be harmed by the lube? Don't know, never tried it.
How else could I utilize that 1/4-20 hole to take a pressure reading on molten boolit lube?

[square butte]

Jim from Floyd may be smiling and chuckling

[gtgeorge]

My thinking for hooking up a pressure gauge would be to use an adapter just as I do when reading transmission pressures. I have the quages and likely the adapter to test mine and I think pressure will go down as the wax becomes liquidous since the piston and bushing are not sealed from leaing and designed to push lube in a semi fluid state. Either way I look forward to comparing pressures and others that can do the math to calculate the possibilities. [smilie=f: I will try to do this at some point during the weekend on mine.

[cbrick]

John (winelover) recently bought this mold and was complaining the boolits wouldn't drop, had to beat the heck out of the hinge pin to get them out. He brought the mold over to my place and I tried casting with it with my alloy. I cleaned the mold with my usual method & pre-heated it in the mold oven & cast at 700 degrees (PID controlled Magma pot). The boolits released fairly well, usually 2 boolits fell out and 2 took a couple of taps to drop, not too bad. I pre-heated the mold too hot and the result was cracking inside the lube groove, cooling the mold with a fan solved that problem.

I had two thoughts after casting with this mold. The first was that I was surprised that Miha made these molds with such a deep lube groove. The second and more important was what happens to that very thin section of boolit at the lube groove when subjected to peak pressure when firing? I would sure like to see some of these recovered boolits & inspect the lube groove.

I can easily see Tim's theory of hydraulic pressure causing the cracking being correct especially if he cast with the mold/alloy temp too high and a low Sn alloy. So if hydraulic pressure can cause that what about peak pressure and especially with faster powders?

Rick

[jmorris]

Now, that lock screw hole is 1/4-20 threads. Does anybody have a pressure gauge they could loan me that would fit in that thread? I've got bupkis for hydraulic pressure gauges around here, and I would think they might be harmed by the lube? Don't know, never tried it.
How else could I utilize that 1/4-20 hole to take a pressure reading on molten boolit lube?
I would make you an adapter to go from 1/4-20 to 1/8" NPT and you could get a gauge of your choice at a local welding supply.

[MBTcustom]

I would make you an adapter to go from 1/4-20 to 1/8" NPT and you could get a gauge of your choice at a local welding supply.

I can make an adapter easily enough (although the further you get the gauge from the source the worse the reading will be) but what pressure gauge is there made that will allow molten boolit lube to be squirted into it? Also, as soon as the hot lube get's into/up to the gauge, it will solidify again and screw things up?
What sort of gauge should I be looking for? Is there one that does not require the stuff being tested to be inside the gauge?

Rick, the one difference that I see between the pressure that the Star puts on the boolits and the pressure that the cartridge puts on them is that the Star is applying pressure inside the lube groove which would try to force the metal on both sides of it apart, while the pressure the cartridge applies to the rear of the boolit will only serve to compress the lube groove, forcing the lube towards both ends of the boolit.
Like so many things, I think the boolit would be much stronger under compression than it would be under tensile strength.
Personally, I really like this boolit design for reasons I outlined in my latest threads on boolit deformation at launch, and accuracy in the M1A. I suspect that the boolit was designed for strength under the stresses of firing, not necessarily sizing.

[btroj]

Would it be somewhat easier to determine the pressure required to break a bullet at the lube groove then decide if it was reasonable to obtain that pressure from the sizer?

I happen to have an engineering student willing to do the math.

[ssnow]

..... the Star is applying pressure inside the lube groove which would try to force the metal on both sides of it apart,....

I think there you have it in a nutshell. It would not require enough pressure to fracture or deform lead as we would usually think of in those terms, it only has to push apart a very thin section. A section that is weak due to design, and of the whole bullet, the most likely to have a defect if there is to be one. A section that at that point, has already been compressed by the punch, if there is any compression to be had.

[VHoward]

The amount of compression would be very hard to measure as it isn't going to compress much. That lube groove is a weak point whether there was a flaw in the bullet or not. I have had 9mm bullets that had deep lube grooves do that. I may have been casting them too hot, i don't know. This really isn't anything to be making a federal case over though. I just toss them in the pot to be recast.

[ReloaderFred]

You guys find the darnedest things to argue over................

Fred

[6bg6ga]

You guys find the darnedest things to argue over................

Fred

Thats what keeps it interesting.:smile:

[MBTcustom]

You guys find the darnedest things to argue over................

Fred

I'm not arguing. I'm stating fact, and waiting for everybody to realize how right I was all along!
:kidding:

[jmorris]

I can make an adapter easily enough (although the further you get the gauge from the source the worse the reading will be) but what pressure gauge is there made that will allow molten boolit lube to be squirted into it?

I have a corner weight gauge that uses water (actually antifreeze) that has a point gauge that is 1 cubic inch in diameter that the other end is connected to a pressure gauge.

In the old days, it is what we used to corner weigh race cars. I only use it anymore to check trailor toung weight. Lots of ways to measure things.

Just fill the container/piston with something that wouldn't squirt the fluid right past and measure the pressure or look for the high point in the curve.

Likely not worth he effort but would be neat to know....

[MBTcustom]

If you hold a grease gun upside down next to the Star sizer, you suddenly realize where some of the inspiration for the design came from.
The Star sizer is just an upside down grease gun with a shorter stroke.
Just throwing it out there.

[6bg6ga]

common design for a number of different uses.

[gtgeorge]

And a grease gun has a rubber seal that stays tight against the bore to push the grease as well. ;)

[M-Tecs]

For the people that want to do the math.

http://www.glasscampus.com/tutorials/pdf/Stretching%20Lead.pdf (http://www.glasscampus.com/tutorials/pdf/Stretching%20Lead.pdf)

http://www.eng-tips.com/viewthread.cfm?qid=180873 (http://www.eng-tips.com/viewthread.cfm?qid=180873)

http://www.glasscampus.com/tutorials/pdf/Stretching%20Lead.pdf (http://www.glasscampus.com/tutorials/pdf/Stretching%20Lead.pdf)

http://mysite.du.edu/~jcalvert/phys/lead.htm (http://mysite.du.edu/~jcalvert/phys/lead.htm)

http://www.ila-lead.org/UserFiles/File/factbook/chapter2.pdf (http://www.ila-lead.org/UserFiles/File/factbook/chapter2.pdf)

[ssnow]

Do you know how to tighten the tracks on a Bulldozer? A grease gun :)

[longbow]

Slightly off topic but I am with cbrick on the thin stem collapsing under high firing pressure. I do not like any of the designs with extremely deep lube grooves/small stems for that reason

I can state for a fact the a Lyman 429421 can collapse at the lube groove under the compression of a top end powder charge because I have recovered boolits that collapsed at the lube groove. These were cast of range scrap and air cooled. They seemed slightly softer than ACWW but not hardness tested.

Tim: Since you will not be checking hydraulic pressure of flowing lube the distance the gauge is from the piston doesn't matter. Once pressure is built up it is static pressure so makes no difference as to distance.

As for lead tensile and compressive strength, I believe lead like most ductile materials has about equal tensile and compressive strength but I will check to see if I can find some back up. Lea dis an odd one because it creeps so badly that tensile strength is hard to measure accurately... at least with near pure lead.

Longbow