DIY Commercial Group Manual Lever (now with videos) - Page 5

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pizzaman383 (original poster)
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#41: Post by pizzaman383 (original poster) »

Stephane_Paris wrote:You don't seem to apply such force to put down the lever :shock:

Interesting :)
For those interested in how this is possible, the lever on this group provides a 15x1 mechanical advantage and it is pushing a 50mm diameter piston. The lever is 280mm long to point where I press. I can't remember the proper formula. Anybody else remember?

I do know that I can press hard enough blow past the group seal (tested usubg water and a scace-like orifice).
Curtis
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jpender

#42: Post by jpender »

With a 50mm diameter you need to apply 45 pounds for each bar of pressure. A 15:1 advantage reduces that to 3 pounds per bar. My manual lever, a Robot, requires about twice as much force.

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pizzaman383 (original poster)
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#43: Post by pizzaman383 (original poster) » replying to jpender »

Thanks! That perspective is very helpful.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

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Stephane_Paris

#44: Post by Stephane_Paris »

jpender wrote:With a 50mm diameter you need to apply 45 pounds for each bar of pressure. A 15:1 advantage reduces that to 3 pounds per bar. My manual lever, a Robot, requires about twice as much force.
The spring of my Strega if Soo powerfull so :shock:
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Bluecold
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#45: Post by Bluecold »

If you can blow past the seal with just hand pressure your seal is compromised. A seal such as that should hold 100 bars without breaking a sweat. Any hydraulic bottle jack also has a thin ring holding the pressure in, and those need to hold in much much more pressure.
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truemagellen

#46: Post by truemagellen »

This is a much better idea than trying to find a La Pavoni Pub with its wonky thermosyphon and limited boiler size

bravo!

pizzaman383 (original poster)
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#47: Post by pizzaman383 (original poster) »

Bluecold wrote:If you can blow past the seal with just hand pressure your seal is compromised. A seal such as that should hold 100 bars without breaking a sweat. Any hydraulic bottle jack also has a thin ring holding the pressure in, and those need to hold in much much more pressure.
who said it was just hand pressure? I was curious how far I could take the pressure so I locked my arms/chest and leaned a significant amount of my body weight into it.

but you may be right that my gasket could be in need of replacing.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

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naked-portafilter

#48: Post by naked-portafilter »

Unfortunately, we are under extreme pressure now but sometimes in the coming weeks/months :-( we will most definitely mod our first prototype yoke and a fork to see how it works. I like this group head a lot and it will be fun to get to know it even better.