nater Posted April 15, 2013 Share Posted April 15, 2013 Yes, hyrdaulic systems are recommended, not pneumatic. I press my stars between 1000-2000 psi on each star. The total pressure you will need depends on the number of pins on your star plate. Most of my plates will need around 4000-5000 psi. Link to comment Share on other sites More sharing options...
pyromagi Posted April 15, 2013 Share Posted April 15, 2013 If you press a single star with 1000-2000psi wouldn't that only let you press 2-5 stars in a starplate if you were to apply 4000-5000psi on the plate?Since i already have a compressor and the tools/materials to build the stand for a pneumatic cylinder i thought that was the way to go.Let's just for the sake of it say that i decide to go with pneumatic instead of hydraulics, what pneumatic cylinder would suffice for lets say 10x10 starplate 3/8"?I have been trying to calculate but my math isn't that good. Let's say a pneumatic cylinder is able to produce between 1500 and 7800 Newton.And the area of one 3/8" pin is 71.3 mm2,If i were to build a 100 pin starplate that would equal max 7800N on totally 7130mm2 (~ 78N / 71,3mm2).How do i convert that to psi? Kind Regards Link to comment Share on other sites More sharing options...
nater Posted April 15, 2013 Share Posted April 15, 2013 I don't make big shells which take big shells. My PtoF gauge is my limiting factor, my press has room to go when the gauge is tapped out. Recently I have been pressing 1/4" stars on 56 pin plate which takes 5000 psi to get about 1700 psi on each star. I am not familiar with the units you listed enough to convert them without looking it up. Link to comment Share on other sites More sharing options...
pyromagi Posted April 15, 2013 Share Posted April 15, 2013 (edited) Here is a datasheet of the cylinder: https://content2.smc...96-C96-B_EU.pdfIm not sure if my math is ok, but i have come to the following conclusion. 1 N ~ 0,22481 pounds force7800N ~ 1753,5 pounds force 1 mm2 ~ 0,00155 sq in71,3305 mm2 ~ 0,1106 sq in (base area of 3/8" starplate pin) Would that give me (1753,5 * (1/0,1106)) / 100 ~ 158.5 psi per star ?? Does that sound right? Edited April 15, 2013 by pyromagi Link to comment Share on other sites More sharing options...
Mumbles Posted April 15, 2013 Share Posted April 15, 2013 Looks about right to me. Link to comment Share on other sites More sharing options...
pyromagi Posted April 15, 2013 Share Posted April 15, 2013 Then that cylinder wouldn't work then.Would 1000psi suffice for 3/8" stars? Kind Regards Link to comment Share on other sites More sharing options...
pyromagi Posted April 18, 2013 Share Posted April 18, 2013 Is it worth to go with double acting cylinders instead of single acting?I have been looking at some Enerpac and BVA cylinders and the 15 ton cylinders look pretty nice.I still need to hand pump them, but I guess i can live with that Link to comment Share on other sites More sharing options...
Wildcard Posted June 18, 2013 Share Posted June 18, 2013 $750.00 complete: You wouldn't happen to have a parts list for this or better yet links to the parts for us lazy basterds? Link to comment Share on other sites More sharing options...
SekndAmendment Posted June 18, 2013 Share Posted June 18, 2013 (edited) I'll throw in my two-bits on this topic: I'd go with hydraulics over pneumatics for a lot of the reasons listed above. You could go with double-acting if you'd like but it isn't really necessary. I always tell people to be careful when working with double-acting hydraulics. For some reason calling it a "press" gets the idea in our heads that you only have to be safety conscious when the piston is on the way down. Not a lot of people get pinched or crushed while the "press" is pressing. Accidents typically happen when the thing is on the way back up. Hydraulics are a bit safer because of the smooth operation and the fact that they don't explode when the pressure system is compromised, they just leak. That can be dangerous too of course. Check out some google images of hydraulic injection injuries. But don't stress about it too much. If you've purchased the pressure system the chances are that if your press fails, it'll fail by bending or breaking the brackets you've made. The piston will be just fine. Edited June 18, 2013 by SekndAmendment Link to comment Share on other sites More sharing options...
WSM Posted June 21, 2013 Share Posted June 21, 2013 (edited) how much lexan will keep me out of the ER Some is better than none, but more is better yet. If you can get 1/4" Lexan (polycarbonate) sheet, you can double or triple it for as much or more protection than thicker sheet. The best mounting techniques I've seen involve solidly mounting the sheets in a steel frame and clamping the edges of the shield rather than drilling holes through it. If several sheets are layered, space the sheets rather than place them next to each other. This way the potential impact energy is transferred laterally to the frame. WSM Edited June 22, 2013 by WSM Link to comment Share on other sites More sharing options...
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