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Author: Subject: Simple shielded lever press
Hennig Brand
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[*] posted on 16-3-2015 at 15:49


Combination metal phallus and precision tubing cutter, of course it is painted green though which disguises its true form a bit. :D
In all seriousness you did do a nice neat job of building it and it looks like it works well. Good job!
I think I will stick with a utility knife and a wooden cutting board, but you do have the capability of making a lot of precision cuts very quickly and easily which could be a real advantage to anyone making large numbers of cuts at a time.




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markx
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[*] posted on 16-3-2015 at 16:18


Quote: Originally posted by Hennig Brand  
Combination metal phallus and precision tubing cutter, of course it is painted green though which disguises its true form a bit. :D
In all seriousness you did do a nice neat job of building it and it looks like it works well. Good job!
I think I will stick with a utility knife and a wooden cutting board, but you do have the capability of making a lot of precision cuts very quickly and easily which could be a real advantage to anyone making large numbers of cuts at a time.


I tried the knife and brasilian pine board method, but achieving repeatablility and a staight cut drove me to drink....which, given my unrestricted access to unlimited amounts of highly purified palatable alcohol, seemed like a really bad set of circumstances...hence the camoflaged green metal dick with a precision blade :D :D




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Fulmen
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[*] posted on 16-3-2015 at 23:03


First off: Nice work. But think about what happens if something goes off. It will push the lever you're holding upwards with tremendous force, are you sure you'd like to experience that? As a minimum I'd add a long wooden handle sized so it'll break, that must be better than trying to hold down the entire blast.
A proper torque wrench "releases" once the proper torque has been reached. So not only would it limit the force applied but also "give" if a detonation occurs. It would also produce a repeatable force without staring at a gage, a great plus for repeated work.





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[*] posted on 17-3-2015 at 01:34


Quote: Originally posted by Fulmen  
First off: Nice work. But think about what happens if something goes off. It will push the lever you're holding upwards with tremendous force, are you sure you'd like to experience that? As a minimum I'd add a long wooden handle sized so it'll break, that must be better than trying to hold down the entire blast.
A proper torque wrench "releases" once the proper torque has been reached. So not only would it limit the force applied but also "give" if a detonation occurs. It would also produce a repeatable force without staring at a gage, a great plus for repeated work.



The wooden handle is a very good idea! I did see Hennig's press in one thread and it was entirely composed of wood if I remember correctly...a nice safety release if properly shielded against high velocity shrapnel.
I've been thinking about it a lot in terms of what happens if a charge does go off in the compartment and swings up the back of the handle. It can easily break ones hand or worse. An even scarier scenario would be if the back of the handle is is held down with enough force to cause the bolt in the front end to break instead and then the handle and the shield swing up from the front and towards the face of the user....
Another danger is the loading pin...if a metal one is used then this thing becomes a deadly high energy projectile that can penetrate the top of the shield and lever. A wooden pin is hence the preferred choice, it will shatter and dissipate the energy in case of a mishap.
Taking all of that into account I never stand directly behind the press while compacting a load, but rather on the side, nor lean over it while applying force.


[Edited on 17-3-2015 by markx]




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[*] posted on 17-3-2015 at 03:11


How about a 30 foot long wooden handle ;)



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Hennig Brand
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[*] posted on 17-3-2015 at 11:02


A hole right through the lever could maybe be made which the loading rod could fit into. The pin (bolt?) holding the loading rod to the lever could allow the loading rod freedom to move (pivot point) as well as act as an effective shear pin if its size and strength were properly selected. The pin could be made to be the weak link. Just keep your body away from above the loading rod during pressing, since it could end up traveling at very high velocities in the upwards direction.


[Edited on 18-3-2015 by Hennig Brand]




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[*] posted on 19-3-2015 at 11:40


Yes, the pivot point under the lever for the loading pin is a very good suggestion...I've was thinking of implementing that part, but since this press was meant for sub gram quantities of secondary and the stroke of the pin is quite negligible, I opted for just a slot in the lever.
I guess common sense, a healthy selfpreservation instinct and no time pressure are the energetics experimeter's best allies. I find that sometimes overengineered safety features can to make the process very uncomfortable and provoke mistakes. But by far the rushing of things is a surefire way to a disaster. Hence always take ample time to prepare and think through all operations before commencing with an experiment.




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[*] posted on 19-3-2015 at 14:57


Wise words.

Perhaps a few unmanned experiments would be worthwhile to determine the safest design ?

Edit:

Rig up a press design with whatever, and stick a bucket on the end of the lever.

Use a Hosepipe to remotely add water to simulate the pressure.

If the bucket survives an explosion with it's water intact, a human operator should, as we're more-or-less the same thing.

[Edited on 19-3-2015 by aga]




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Hennig Brand
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[*] posted on 20-3-2015 at 18:32


The end of the lever could have a handle which pointed straight down and was round and relatively smooth. If detonation occurred during loading and the lever flew up quickly the handle would be pulled from the operators grip rather than seriously injuring him or her. Just don't hold your head or body over the lever when pressing.



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[*] posted on 21-3-2015 at 04:31


Quote: Originally posted by Hennig Brand  
The end of the lever could have a handle which pointed straight down and was round and relatively smooth. If detonation occurred during loading and the lever flew up quickly the handle would be pulled from the operators grip rather than seriously injuring him or her. Just don't hold your head or body over the lever when pressing.


Ya...how long do you estimate would it take for me to stop jerking down on that handle end and start pushing on the lever instead :D ? I would also have to weld sharp spikes on and around the lever to prevent that from happening :D :D




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Hennig Brand
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[*] posted on 21-3-2015 at 10:38


Ok, I get the sense you think it would be very difficult to use. :D
Yeah, you could be right. However, with the right mechanical advantage (long enough lever) it wouldn't need to be that hard. Not as convenient you are right.




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