Can you add "torque" indicator to a press?

Torque indicator?
Torque is twisting motion force like what is present on the end of electric motor out put shaft.

I'm guessing you want to know the amount of force the press's ram is applying upwards when you lean downwards on the press handle.

I would think the problem could be solve by measureing from the lever end to the pivot point and multiplying that distance by the weigh you apply to the end of the press handle (the weight you apply could be measured with a simple spring scale).

I think you may have to subtract the length between the linkage pivot point and the axle that attaches the linkage to the end of the ram. Also the weight of the ram and the weight of linkage from the ram end to the pivot point would need to be subtracted from the input weight that you apply.

Might be easier to call the press manufacture and ask what the mechanical advantage ratio of their press is.
Example 1:4 ratio, 25 pound of down ward pressure on the handle equals 4 x 25 = 100 pounds of up ward thrust on the ram.

I have seen information from a Lee Precision stating that their collet die should use X amount of foot pounds when sizing a case or factory crimping with their factory crimp die.

Since the only foot pound indicator I'm familiar with is a "torque wrench", I used that as an example.

Any ideas?

quote:

Example 1:4 ratio, 25 pound of down ward pressure on the handle equals 4 x 25 = 100 pounds of up ward thrust on the ram.

That's true to a point but it's not quite that direct. The leverage principle you cite is valid for a simple lever system when the load is perpendicular to the lever. But, reloading presses have a leverage system that swings and constantly rotates so the force quickly changes from perpendicular, effectively changeing the fulcrum point during lever travel. That fulcrum change vastly increases the lever's force as the ram lifts!

I know of no way to (simply) measure or calculate the force applied to a press ram, which I assume is the point of the question. At least not without doing the calculations you suggest but using calculus that includes the constantly changing toggle/fulcrum during ram travel.


Rusty: "Any ideas?"

Yeah, it's a "feel" thing.

I adjusted my first Lee Collets so the start of pressure came with the lever horizontal and put what I thought would be about 15-20# of force. Removed the case and tried a bullet for fit, if it went in easily I obviously hadn't pushed hard enough so I tried it over until it would not. Then remembered that amount of force for the next one, didn't take long to develop the correct feel. That was maybe 20 years ago and the feeling hasn't gone!

Now, an observation on the Lee collet; it generally only gives us 1 thou of "bullet tension" but believe me, that's plenty. No bullet can possibly be pushed into an undersized hole and leave it loose enough to let you pull the bullet or rotate it with your fingers!

Actually, any neck "tension" from a diameter smaller than 1 thou under bullet diameter is meaningless. Smaller necks just permanently stretch during bullet seating so the remaining case "springback" is only about a thou no matter how much smaller it started. BUT, high seating pressure due to a too-small neck DOES increase average bullet run-out and that is not a help for accuracy.

The Lee Collet is a GOOD neck die. It's perhaps the best available at any price to reload for factory/SAAMI chambers and common cases!

You do need to understand that once you've pushed the necks down to the mandral that's as far as they're gonna go, pushing harder simply stresses your press and die without doing anything to the necks. If you press too hard you will strip out the die's soft aluminum top cap, it's made to do that to protect everything else. A replacement top cap is much less expensive than a new press or die body!

About the Lee neck sizing die, I was informed by Lee Presision that if you see striation lines being extruded up on the case neck surface then you are using too much force during sizing.

With the two Lee FCD have I can look into the top of the die and see the collect finger close together. Once the collect finges come together you have achieved maximum crimp.
I don't actually put my face right over the die with that primed,powdered, bulleted case sitting in the die that creeps me out, but I can still see into it well enought to see the collet figers close.

On press linkage design, I'm not a mechanical engineer my only thought on the press linkage system is that it keeps the ram from bending like a banana when you try raise it up.
I don't know if the linkage system provides compound mechanical advantage like the handles on a pair of Wiss avation tin snips.

quote:

Originally posted by Jim C. <><:
I know of no way to (simply) measure or calculate the force applied to a press ram, which I assume is the point of the question.

Well, the "easy" way is to mount strain gauges lengthwise on the top/bottom side of the handle (near the pivot point for better sensitivity) and tie those into a readout device. To "calibrate" (that ought ot set someone off) simply place a "master" force gauge between the ram and the top of the frame and set the handle readout to match the master gauge at both a low and a "high" handle force.
It won't be a ASTM/NIST tracable system, due to variable friction in the pivot linkage and ram, but it'll be close enough for "govt work".

Thanks again guys! I have been using the Lee Collet dies for a bunch of years. It has always been a "feel" thing for me as well.