rocketboy242 Posted March 12 Posted March 12 (edited) Looking for help to convert 7000lbs force on comp to psi on the following. Piston bore is 3" diameter, the ram rod is 1 -1/4" diameter, and I am using a 3/4" solid rammer on the comp. I want to achieve 7000lds of force on the comp. please provide the the target on the psi gage attached and the conversion formula if possible. Thank you Edited March 12 by rocketboy242 wrong pic
Carbon796 Posted March 12 Posted March 12 Piston bore and ram rod ? Is the hydraulic cylinder that's on your press ? If so, that information isn't need. Assuming that your ptof gage is direct reading. Surface area of 3/4"tooling is .4418 x 7000psi = 3092.6 on your gage.
rocketboy242 Posted March 12 Author Posted March 12 Thanks for the reply, Yes, I have a hydraulic press with a 3" diameter cylinder pushing an 1-1/4" rod that in turn pushes on the 3/4" drift. I understand that the 1-1/4" rod doesn't factor in but I thought the cylinder diameter factored into the equation some how? so 3092 psi on the gage? That seems too high?
Carbon796 Posted March 13 Posted March 13 The cylinder diameter would only come into play. If you were reading the actual pressure being applied to the cylinder. And not using a PtoF gage. Think of the PtoF gage as a short cut. Your reading the actual force being applied through the 3/4" rammer. Regardless of what pressure may be developed in the press cylinder, or its piston size.
rocketboy242 Posted March 13 Author Posted March 13 My apologies for not clarifying. The pressure gage is reading the pressure off the hydraulic cylinder. I don't have a pressure to force gage.
Carbon796 Posted March 13 Posted March 13 (edited) In that case " I think " you're going to want 438psi on your cylinder gage. Piston surface area 7.069 x 438 = 3096.2 force applied to 3/4 rammer. You may want to get ahold of rocket master Dave F. Edited March 13 by Carbon796
DavidF Posted March 13 Posted March 13 Lol, my math stinks! I use charts that came with my first Wolter tooling and a P to F gauge. I'm thinking this is more of a Frank Rizzo question?
PyroGnome Posted Saturday at 09:06 PM Posted Saturday at 09:06 PM @Carbon796's math appears correct. I'm pretty sure (somebody correct me if I'm wrong) that you'd need to subtract the area of the spindle hole on the hollow rammers from the outer area to get a close-to-constant PSI throughout the spindle section. I'm also pretty sure everybody ignores this (it's probably beneficial to have the comp around the spindle compressed more heavily anyway). For example on Caleb's extreme strobe tooling it looks like the hole diameter in the longest rammer is 0.39" on the 1lb tooling, if I subtract that it gives me a pressing area of 0.322 instead of 0.442... makes a big difference in these calculations. If I did the math right pressing at 438 on the press gauge will give you ~9600psi on the comp instead of 7000 which is a kinda huge difference. The next rammer will be lower, and it'll finally be 7000 at the flat rammer.
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