jmorris
Member
- Joined
- Sep 30, 2005
- Messages
- 24,392
It's a question I have had before, years ago, after I had more than one press and noticed the force required on one was different than the force required on another, while doing the same tasks. Any way a question on another forum had me take another look at the question and make an attempt at an answer.
I started off building a simple hydraulic load cell, where the piston has one square inch of area and a gauge that reads in pounds per square inch. I placed it in a press I had and pulled the handle with 5lbs of force and found a 8:1 force multiplication but that was with the ram 2" from the top of its stroke. With the linkage most presses have things don't get powerful until you are closer to the dead spot or "cam over" and I can't make a load cell that short.
So I dug around in my stuff and threw this contraption together, that threads in where the die would and transfers the force of the ram to up above the press and I can adjust the point at which I measure.
To keep things simple and repeatable I am thinking of setting a case in the shell holder/shell plate and lowering the gauge to contact the bottom of the case. Then lower the ram and dropping a shim inside the case. This way I can at least make sure I am measuring all of them at the same height/portion of stroke.
When I got it finished I set it in my Co-ax and found that just the weight of the handle, at dead spot point, was applying over 50lbs of force, so I might need to change the gauge or build another cell. When I get some more time, I'll play a little more and post some results.
I started off building a simple hydraulic load cell, where the piston has one square inch of area and a gauge that reads in pounds per square inch. I placed it in a press I had and pulled the handle with 5lbs of force and found a 8:1 force multiplication but that was with the ram 2" from the top of its stroke. With the linkage most presses have things don't get powerful until you are closer to the dead spot or "cam over" and I can't make a load cell that short.
So I dug around in my stuff and threw this contraption together, that threads in where the die would and transfers the force of the ram to up above the press and I can adjust the point at which I measure.
To keep things simple and repeatable I am thinking of setting a case in the shell holder/shell plate and lowering the gauge to contact the bottom of the case. Then lower the ram and dropping a shim inside the case. This way I can at least make sure I am measuring all of them at the same height/portion of stroke.
When I got it finished I set it in my Co-ax and found that just the weight of the handle, at dead spot point, was applying over 50lbs of force, so I might need to change the gauge or build another cell. When I get some more time, I'll play a little more and post some results.