Home-Barista.com

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

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).

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.

Thanks! That perspective is very helpful.

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

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.

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

bravo!

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.

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.