Rocket Press

[hondo]

I fixed my bottle jack and attached a pressure gauge, I also signed up for pass fire, in the rocket section there is a calculator for detrrmining pressure, when I calculate it I come up with about 3500 psi, on the site it comes up to 1918 psi, I am making 1 pounders, 0.750 Id, my press ram is 1.375 and the rammer is 0.747. I tried to press on last night and can get to 3500 with out cracking the casing, is the calculation on passfire the right pressure?

[Mumbles]

Where are you getting the force measurement? Are you just using the maximum your press can produce, or do you have a gauge of some sort?

[hondo]

Yes I have a pressre gauge, and that is where I am getting the readings

[FrankRizzo]

What's your gauge pressure reading?

[hondo]

sorry, but read my first post cause I told you that there. The question is if any one has a pressure gauge on their hydrolic press and pressing 1 pound rockets what pressure are you pressing them. If I press at 3500 psi I split the casing on purchased tubes not hand rolled

[Mumbles]

In your first post you say when you calculate it, you get 3500. You never state this is a reading in anyway.

 

Anyway, assuming it's the actual pressure being read by the press, you have roughly 11750 psi on the tooling. Even higher if using a cored rammer, such as one used for ramming nozzles.

 

It's really easy if you look at the units. 3500 pounds per square inch. Pounds is the force. So multiply this by the area of your ram, which is 1.4848 sq in. This gives 5196 pounds of force. Divide this by the area of your ram, which is .4382 sq in, and you get your value.

[NightHawkInLight]

The first post says it comes to 1918psi on site. I don't know if that was an edit or not.

[Mumbles]

I think he means passfire when refering to "the site". Thats the way I read it at least.

[hondo]

Ok on passfire, in the rocket section there is a fill in the blank formula section for pressing rockets and when I enter the variables the pressure at the gauge says 1918 psi. and in the formula section when I work out the formula and enter the same variables I get a differnt answer( 3500 psi), so am I to assume I calculated it wrong or passfire is wrong, all I know ,I cannot press the black powder fuel to 3500 psi (gauge reading) with out splitting the casings

[Mumbles]

I understand what you're saying now. You calculated it wrong, passfire is right. With your setup, the following are your values

 

Gauge Reading - applied pressure

1918 - 6500psi

3500 - 11750 psi

 

You want 1918 on your gauge for BP rockets.

[hondo]

thanks thats what I needed to know, now I just need to redo my press for a more stable one. threaded rod streachs too much, Like always I could have purchased a press at harbor freight for the time and cash that I have in the home made one