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!
Attachment 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.

[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.