Riddle me this: Shorter handle on single stage press

[468]

I am considering using a shorter handle on my Hornady Classic press. I don't load anything that requires much leverage, so figured the shorter handle would reduce the throw, and be a bit more efficient. I called Hornady to check the price on a new handle(about $35) and mentioned what I intended to do. I didn't order it...was going to consider other options.

5 minutes later I get a call back from the Hornady rep advising that the engineers said DO NOT do this. You may damage the machine, and void warranty. I replied that if I did, "they" would never know it, and how would it damage the machine? I don't load anything that requires much leverage (I have a Rockchucker for that). The sales rep said it would overstress the linkage where the arm attaches. She offered for me to speak to an engineer, but none were available at the time. This was a very friendly exchange. I just wanted to wrap my head around the "over stress the linkage" issue.

What difference would there be? Within normal, hand gun caliber parameters, what could cause a problem?

Please educate me.

[gareth96]

So with a shorter handle you are going to cause more stress to the linkage? errrr....

My only thought would be that with a shorter handle you won't have the 'feel' you do with the longer one. So maybe seating primers wouldn't give you the same feel and might result in primers not being fully seated, or maybe a little crushed.

[Conditor22]

Hornady's response is really surprising. Many manufacturers offer different length handles for their presses. I'm no rocket scientist, but I see no way you could damage a press by using a shorter handle.:veryconfu

[44magLeo]

I think perhaps the sales rep misunderstood what you meant. A longer handle might overstress the linkages. A shorter handle would put less stress on the linkage. Just basic math tells you that.
Changing the length of the handle on some of Lee's presses is one of there selling points.
For heavy duty jobs leave the handle out long, for less strenuous jobs, like handguns, shorten the handle. The shorter handle throw can speed up things a bit. Less arm movement may help out us older folks with arm or shoulder problems.
What I might do got the hardware store, buy a length of round steel rod the right size, thread it as needed to fit the press. Cut to the length you want. Drilling most any round ball for a knob on the handle isn't hard to do. A pool ball, Golf ball. A wood round ball from the same hardware store. A bit of epoxy.
Leo

[JBinMN]

I am betting it was a "failure to communicate" error on their end from the sales rep to the engineer. There seems to be no reason that a shorter arm would cause issues that I can think of right now. Although I am not familiar with that press & do not own one, as well as I am not an mechanical engineer, but my Dad was and maybe just a little bit of knowing how "mechanical advantage using leverage" rubbed off on me, & I reckon I am old enough with enough experience using leverage, to make my opinion.

Do as ya like, but I would just use a shorter handle anyway.
;)

G'Luck!
:)

[RED BEAR]

Sounds like a load to me. I use a short handle on my lee press for that exact reason . A shorter handle can't put more stress than a long handle. Have had a few discussions with hornady customer service . As a result i will never purchase anything with there name on it again.

[country gent]

I believe one of the advantages of the shorter handle and lessened leverage would be a better feel of what your doing. One of the things the short handle for the coax is recommended for. The shorter travel is also a benefit. The faster movement may be a drawback though. Having seen handles made both longer and shorter over the years on presses and other equipment I don't see where a shorter handle will stress linkages. I could see a shorter handle causing clearance issues with travel and the operating hand at times. ( Some bottom ram press the shorter handle will put the hand very close to the press frame possibly making for occasional bruised knuckles). Both the coax and summit presses have short handles offered for them from the manufacturers.

I would make one and try it see how it works most press handles are a simple threaded affair or pipe set in a socket and pinned in place. As I said you may want to bend it for an offset on bottom mounter rams for hand clearance. If it dosnt work you can always go back to the original handle.

[DonMountain]

There are at least two components or forces applied to the pivot point on the handle. Moment and shear. If you reduce the handle length and apply the same moment, you will increase the shear. And I am sure you will severely damage that press. So you would have to either increase the pivot pin size to handle the shear loadings, and the casting the handle is screwed into, or use stronger and harder metals to allow the much larger stresses. So, I recommend not doing it if you are going to be sizing 50 BMG brass down to much shorter 22 caliber pistol rounds and you are Hulk Hogan. On the other hand I am not Hulk Hogan so I would do it. Most people are not strong enough to break a modern press no mater what you do to it.

[jeepvet]

That lady must have worked for a health insurance company in a past life. I get the same kind of answers from them.

Remember the old saying, "Don't believe anything you hear and only half of what you see."

[468]

Sooo....I called them again. None of the engineers were available, so I spoke to a tech help guy. He couldn’t explain why there would be an issue. I suggested Hornady consider offering shorter handles for their single stage presses, as do some others.

I’m gonna make one and see how it works...as soon as I get my press back from Hornady after repair.

[Winger Ed.]

Its a lever.

The handle being shorter can't hurt the press any more than a shorter pry bar
would do more damage using it on the same thing as a long one.

[1hole]

It takes a certain amount of the toggle block's camming movement/rotation to accomplish its task, levers are designed long enough to make operating it easy for most folk but that's all.

Buy or improvise the length you want. Shortening the operating lever will certainly increase the needed work on your end but it won't mean a thing to the toggle block ... nor anything else.

[David2011]

Makes no sense. RCBS offers a standard and a short handle for the Summit. Reduced length = reduced leverage = reduced load on the press. To do the same task such as seating bullets in a given cartridge the load on the press will remain constant; you just have to press a little harder on the shorter lever.

[rbuck351]

It takes a given amount of force at the die to do it's job, resizing being the most. How long a handle you use to apply this same given force to the linkage makes no difference to the linkage. It does to your arm though. With easy to size cases, no problem for your arm and certainly no problem for the press. Go for it.

[mdi]

Well, my plain old horse sense tells me "what the Hell difference would it make?". If you exert enough force to F/L size a large case, how would the force on the linkage differ if the initial force is exerted 6" away from the pivot point or 16" away?

[fatboy]

sound more like a CYA/ Liability answer than an Engineering answer. and the only CYA is that any change is bad, so we cannot endorse bad!

[lightman]

It sounds like a mis communication. Either that or that engineer was not at the top of his graduating class!

[468]

I did speak to a mechanical engineer friend of mine. He said a shorter lever, in theory, would put more load on the pivot point...further theorizing that a lever half as long as the original would require twice as much force to achieve the same work.

But, obviously, I would be no where near any maximum effort level, or test any limits, under this scenario.

Noodle on that.

[onelight]

I did speak to a mechanical engineer friend of mine. He said a shorter lever, in theory, would put more load on the pivot point...further theorizing that a lever half as long as the original would require twice as much force to achieve the same work.

But, obviously, I would be no where near any maximum effort level, or test any limits, under this scenario.

Noodle on that.
I still don’t understand it would certainly put more pressure on your hand but from there to the case all parts are bearing the same exact load. I need more learning to understand this math.

[M-Tecs]

I still don’t understand it would certainly put more pressure on your hand but from there to the case all parts are bearing the same exact load. I need more learning to understand this math.

The longer the handle the more leverage you will have and the shorter the less leverage you have. That is simple physics. The claim that there will more load on the pivot is correct in the case of the pivot pin on a press, however, this additional load is a non factor. It could be a factor on something like a kids teeter-totter. Example would be placing 100 pounds on both sides. It will balance and the force on the pivot will be 200 pounds plus the weight of the teeter bar. Now shorten ONE side by half. The shorter side will need an addition 100 pounds to balance so the load on the pivot is 300 pounds plus the weight of the teeter bar. If you keep shortening the one side the more weight you have to add to get to balance. At some point you may get enough weight that the pivot will fail. The extreme example would if one side of the teeter-totter is 10 feet long and the other side is much shorter. At 10 feet verse 1 foot the short side need 1,000 pounds to balance the 100 pounds. At 1 inch verse 10 feet you will need 12,000 pounds to balance the 100 pounds.

Since most presses now use a compound leverage system so this is even less of a factor. This compound leverage can produce thousands of pounds of force on the pivot. Adding an additional 20 or 30 pounds of downward force by choking up on the handle or using a short handle is a non factor in the case of a press.

[onelight]

It just seems to me that is is going to require the same amount of force to resize a case and thus the same amount of force is being transferred through the the press to accomplish the same task
A shorter handle reduces the amount of force I can put on the press not increases it. Although with the shorter stroke I might increase the speed for a full stroke on the press. The short handle reduces my hand movement but changes nothing in the mechanical leverage designed into the press. I have a son that is an engineer for Boeing I get him draw me a picture :-P

[M-Tecs]

It just seems to me that is is going to require the same amount of force to resize a case and thus the same amount of force is being transferred through the the press to accomplish the same task


It is correct that at the die the ram force is the same.


A shorter handle reduces the amount of force I can put on the press not increases it.

To get the same force at the die and ram with a shorter handle you need increase the pressure at the handle. This increased pressure is transferred to the pivot pin. In the case of a press there is so little difference it truly is a nonfactor. On something like a counter weight crane this becomes a real issue. The shorter the counterweight side is the more weight you need to balance. This means the pivot has more weight on it to balance.

238665

[jmorris]

Very little load is on anything until the very last part of the stroke both in and out of the die. Then forces go very high, very quickly.

Maybe they figured if you had to ask, you shouldn’t be messing with it.?

Forster offers different length handles for their press and a number of others are adjustable from a Lee single stage all the way to the Dillon 1050.

[mdi]

If you used a lever with a fixed pivot point, and raised 50 lbs with a 6" lever, the only change if you used a 12" lever would be less force to move that 50 lbs. at the end of the lever. The same force would be on the pivot and the same force on the same length arm beyond the pivot point...

[M-Tecs]

If you used a lever with a fixed pivot point, and raised 50 lbs with a 6" lever, the only change if you used a 12" lever would be less force to move that 50 lbs. at the end of the lever. The same force would be on the pivot and the same force on the same length arm beyond the pivot point...

No sense in arguing about it when a test is so easy to do. Take a 12" ruler and lay it across a pivot point like a round pen. Place a quarter on each end so it balances. Now move one quarter half the distance to the pivot. Too get it to balance you have to add more weight to the the side you moved. This extra weight it transferred to the pivot.

[kenton]

The longer the handle the more leverage you will have and the shorter the less leverage you have. That is simple physics. The claim that there will more load on the pivot is correct in the case of the pivot pin on a press, however, this additional load is a non factor. It could be a factor on something like a kids teeter-totter. Example would be placing 100 pounds on both sides. It will balance and the force on the pivot will be 200 pounds plus the weight of the teeter bar. Now shorten ONE side by half. The shorter side will need an addition 100 pounds to balance so the load on the pivot is 300 pounds plus the weight of the teeter bar. If you keep shortening the one side the more weight you have to add to get to balance. At some point you may get enough weight that the pivot will fail. The extreme example would if one side of the teeter-totter is 10 feet long and the other side is much shorter. At 10 feet verse 1 foot the short side need 1,000 pounds to balance the 100 pounds. At 1 inch verse 10 feet you will need 12,000 pounds to balance the 100 pounds.

Since most presses now use a compound leverage system so this is even less of a factor. This compound leverage can produce thousands of pounds of force on the pivot. Adding an additional 20 or 30 pounds of downward force by choking up on the handle or using a short handle is a non factor in the case of a press.

That makes sense after I read the explanation twice. It also explains why portaging a tail heavy canoe wears out my shoulders faster.

[468]

[QUOTE=jmorris;4610589

Maybe they figured if you had to ask, you shouldn’t be messing with it...[/QUOTE]

My question to them, before they advised not to do it, was how much a new handle costs.

I’m not understanding your statement.

[onelight]

It is correct that at the die the ram force is the same.



To get the same force at the die and ram with a shorter handle you need increase the pressure at the handle. This increased pressure is transferred to the pivot pin. In the case of a press there is so little difference it truly is a nonfactor. On something like a counter weight crane this becomes a real issue. The shorter the counterweight side is the more weight you need to balance. This means the pivot has more weight on it to balance.

238665
Ok this helps if you had a scale at the pivot on this example and the levers on both ends the same length with say 10lb on each end to balance your scale reads 20lb if you shorten one end so it requires 20lbs to balance the scale would read 30lbs so the load on the scale would have gone up 10lbs.
Aren’t you guys glad you weren’t my teachers in high school. [smilie=b:

[468]

The longer the handle the more leverage you will have and the shorter the less leverage you have. That is simple physics. The claim that there will more load on the pivot is correct in the case of the pivot pin on a press, however, this additional load is a non factor. It could be a factor on something like a kids teeter-totter. Example would be placing 100 pounds on both sides. It will balance and the force on the pivot will be 200 pounds plus the weight of the teeter bar. Now shorten ONE side by half. The shorter side will need an addition 100 pounds to balance so the load on the pivot is 300 pounds plus the weight of the teeter bar. If you keep shortening the one side the more weight you have to add to get to balance. At some point you may get enough weight that the pivot will fail. The extreme example would if one side of the teeter-totter is 10 feet long and the other side is much shorter. At 10 feet verse 1 foot the short side need 1,000 pounds to balance the 100 pounds. At 1 inch verse 10 feet you will need 12,000 pounds to balance the 100 pounds.

Since most presses now use a compound leverage system so this is even less of a factor. This compound leverage can produce thousands of pounds of force on the pivot. Adding an additional 20 or 30 pounds of downward force by choking up on the handle or using a short handle is a non factor in the case of a press.

Great explanation!

[Rattlesnake Charlie]

Somebody failed physics class. In the 8th grade.

[44magLeo]

I can't dispute the claims M-Tecs.
Lets suppose the pivot point is designed to support 10,000 lbs. On the one end the lever is 10 ft long with 100 lbs on it. The other end is 10 ft with 100 lbs on. So load on the pivot point is weight of arms plus load on both arms. Just to keep it simple we'll work with just the load on the arms. Load is 200 lbs.
Let's move the load on one end in to 5 ft. This would need 200 lbs to balance the load thus giving a total load of 300 lbs. Lets even go a bit farther and move the one load into say one ft. That would need 1000 lbs to balance.
This is well with in the capacity of the pivot point.
Most of these heavy presses were designed so they have much more strength than needed to handle any possible load that even very heavy duty operations can be done. I can't think of anything much tougher to do than swaging bullets. Most people that do that often build their own presses for this. These presses are designed to make the task easier for the operator. They want presses that only need the 10 lbs to move the 1000 lb load not a 1000 lbs to move the 10 lb load.
RCBS first designed their presses to withstand swaging bullets and could do so for a very long time.
Resizing cartridges cases stress a press much less than swaging.
Sizing large cases like the 50 BMG is done on a press with about the same mechanical advantage as a regular press has but the an opening tall enough to allow the long case to be easily inserted into the press.
If the press is designed to withstand these severe loads and do so for several life times. Then doing regular loading will not overload anything even with a handle that is much shorter than the stock handle.
Leo

[M-Tecs]

44magLeo as I stated above the very minimal additional loading from a shorter handle in a loading press is a non-factor. While I have never put a load cell between the ram and die I do know you can generate at least a couple of thousand pounds of force due to the compounding linkage . The pivot pins are designed to withstand this level of pressure. Adding 20 or 30 more pounds to this level of pressure from a shorter handle is not an issue. The teeter-totter or balance cranes examples are just an easy way to help understand how a shorter handle will add a very minimal amount of additional loading to the pivot pin since additional force is required when using a shorter handle or chocking up on the handle. The output is the same regardless of handle length but handle length changes or even where you hold the handle changes the input force. This input force change is why the load on the pivot pin changes.


5 minutes later I get a call back from the Hornady rep advising that the engineers said DO NOT do this. You may damage the machine, and void warranty.


Technically the Hornady rep is correct that a shorter handle does introduce addition loading to the system, however, I would be really interested to know how an 20 or 30 pounds addition load to a system designed to deal with several thousand pounds of force is going to damage the press.

[David2011]

The problem I’m having with the teeter totter example is that the amount of work being done changes. In a loading press the amount of work remains fairly constant for a given operation such as sizing .44 Mag cases that were all loaded with the same powder charge and bullet. The work at the ram and therefore the pivot is a constant even though a 20” handle might require 20 pounds of force and a 10” handle would require 40 pounds of force to size the same cartridge.

[M-Tecs]

The problem I’m having with the teeter totter example is that the amount of work being done changes.

No. What changes is an increased load to account for the shorter point of leverage. The work (maintaining balance) output is the same.


The work at the ram and therefore the pivot is a constant even though a 20” handle might require 20 pounds of force and a 10” handle would require 40 pounds of force to size the same cartridge.

The additional 20 pounds of force has to go somewhere. As you stated the work at the ram is constant so the additional force is transferred to the first pivot pin.

[jmorris]

Technically the Hornady rep is correct that a shorter handle does introduce addition loading to the system, however, I would be really interested to know how an 20 or 30 pounds addition load to a system designed to deal with several thousand pounds of force is going to damage the press.

Just so I get this right, if I grab the handle between the ball and the pivot and stroke the press, effectively shorting it by 50%, I can break it?

[M-Tecs]

Just so I get this right, if I grab the handle between the ball and the pivot and stroke the press, effectively shorting it by 50%, I can break it?

No not even close. I don't know this for a fact but I have read that the compound press generate about 3,000 pounds of force at the ram. This load is also on the first pivot pin. Adding an additional 30 pounds would only increase load 1% max.

[rbuck351]

So if I turn the press upside down and shortened the handle this would lessen the pressure on the link pin? Or if I left the handle long so they would balance and just grabbed it shorter the pin load would be the same? Or if I took the press to space in 0 gravity the pin load would be the same short or long handle? If the only difference is the difference in the weight of the shorter handle we could add say a pound or so counter weight to the end of our shorter handle to get balance and the added weight of the counter balance would be the only difference in pin pressure. This is all nice in theory but a pound or so of different load is not even worth mentioning let alone thinking it could damage a press.

[M-Tecs]

So if I turn the press upside down and shortened the handle this would lessen the pressure on the link pin?

No turning the press upside down would not effect the force vectors in the press and the shorter handle still requires an increased load to do the same amount of work. Same for zero gravity not effecting the force vectors in the press other than the actual weight of the components.

If you are having a hard time visualizing it drawn yourself a diagram including the loads and force vectors.

[onelight]

The extra loading on the pivot is = to the extra pressure you feel on your hand when you move your hand to the center of the handle on your press

[rbuck351]

There is no weight in zero gravity and shortening one side of a fulcrum by half would double the amount of force required to do a given amount of work on the opposite side. No more no less. The only difference of force on the pin in a gravity area is the missing piece of the handle and it's distance from the fulcrum. Maybe an additional pound or two. Check it out with a torque wrench.
Lock the square drive in a vice and apply a given weight on the end. Then double the weight at mid point and see if the torque spec doesn't read the same.

[M-Tecs]

Torque is rotational force an no one has suggested it changed in any of the examples.

Do yourself a favor and draw out with arrows indicating were the force loading is and what changes as you change loading for a change in handle length.

Your example of square drive in a vice with at torque wrench and changing weights is easy to visualize. To maintain the same torque you have to double the weight if you shorten the handle by half so the end result is the square drive has to hold this extra weight. Torque doesn't change but shear loading force does. Not an issue until the shear load of the square drive is exceeded. Same for the pivot pin on the OP's Hornady Classic press. The Hornady Rep/engineers statement the shorter handle increase a stress is correct. That doesn't change the fact that Hornady's claim that a shorter handle may damage the machine shows a serious lack of common sense.

[onelight]

If I could mount my press on a scale so the scale reads total weight , the extra pressure required on a shorter handle would read as more weight on the scale , that load is transferred through the press.