Adding a pressure gauge to a hydraulic jack

Messy shop project. Idea copied off one of my pyro mentor’s website.

Picked a 12 ton press off craigslist, first thing I had to do was add a pressure gauge.

First thing, drain the fluid and tear it down. Wearing latex gloves and getting hydraulic fluid everywhere is a good reason not to touch the digital camera for this phase of the operation, but just picture the mess and then triple it!

After thoroughly cleaning the base, the setup begins:

Drill a 3/16 hole about 1-1/2” in, centering in the meat of the base, on the side opposite the rest of the ports.

then open the hole up to 5/16 for the first ¾”. Then run a 1/8” pipe thread tap in.

Clamp the base flat, connect the dots:

Now clean ‘er again, and reassemble, (where did those little parts go?) making note of the diameter of the piston base.

I used a hydraulic “Z” fitting, only rated up to 6000 PSI, probably re-plumb at a later date for full pressure. Anyway, passed the pressure test (the second time around)

Reason for measuring the piston diameter, to make a conversion for hydraulic pressure to lbs of force.  Piston dia = 1.75 inches, giving me an area of a bit over 2.40 sq inches. At 6000 PSI gauge the force would equal about 14,400 lbs. to test my math, at 10,000 psi it figures to 24,053 lbs, probably not a coincidence it’s a  12 ton jack. Now it's time to figure out how to get hydraulic fluid out of my hair.

 Pressure conversion chart Piston Dia 1.75 Piston area 2.4053 416 PSI = 1000 LBS 624 PSI = 1500 LBS 832 PSI = 2000 LBS 1039 PSI = 2500 LBS 1247 PSI = 3000 LBS 1455 PSI = 3500 LBS 1663 PSI = 4000 LBS 1871 PSI = 4500 LBS 2079 PSI = 5000 LBS 2287 PSI = 5500 LBS 2495 PSI = 6000 LBS 2702 PSI = 6500 LBS 2910 PSI = 7000 LBS 3118 PSI = 7500 LBS 3326 PSI = 8000 LBS 3534 PSI = 8500 LBS 3742 PSI = 9000 LBS 3950 PSI = 9500 LBS 4158 PSI = 10000 LBS 4365 PSI = 10500 LBS 4573 PSI = 11000 LBS 4781 PSI = 11500 LBS 4989 PSI = 12000 LBS 5197 PSI = 12500 LBS 5405 PSI = 13000 LBS 5613 PSI = 13500 LBS 5821 PSI = 14000 LBS 6028 PSI = 14500 LBS 6236 PSI = 15000 LBS

 Pressure conversion chart Piston Dia 1.75 Piston area 2.4053 500 PSI = 1203 LBS 1000 PSI = 2405 LBS 1500 PSI = 3608 LBS 2000 PSI = 4811 LBS 2500 PSI = 6013 LBS 3000 PSI = 7216 LBS 3500 PSI = 8418 LBS 4000 PSI = 9621 LBS 4500 PSI = 10824 LBS 5000 PSI = 12026 LBS 5500 PSI = 13229 LBS 6000 PSI = 14432 LBS 6500 PSI = 15634 LBS 7000 PSI = 16837 LBS 7500 PSI = 18040 LBS 8000 PSI = 19242 LBS 8500 PSI = 20445 LBS 9000 PSI = 21648 LBS 9500 PSI = 22850 LBS 10000 PSI = 24053 LBS