[Homeroast] Turning Bottomless Portafilter

Dennis Parham dparham_is at mac.com
Sat Aug 28 11:31:41 CDT 2010


So, your asking for video of shots with nekkid PF?? hehe 

Dennis Parham

Sent from my iPhone

On Aug 28, 2010, at 12:09 PM, Joseph Robertson <theotherjo at gmail.com> wrote:

> This nakid pf thing has just got way out of hand...will someone post a video
> clip so we can get back to baking some beans....;^))))
> JR
> 
> On Sat, Aug 28, 2010 at 9:07 AM, Joseph Robertson <theotherjo at gmail.com>wrote:
> 
>> Now a cup of joe that's another thing all together.
>> JR
>> 
>> 
>> On Sat, Aug 28, 2010 at 9:07 AM, Joseph Robertson <theotherjo at gmail.com>wrote:
>> 
>>> I believe it's been done. Again a vice might be nice and I don't mean a
>>> cigarette while using the grinder....my bad. ;^)
>>> 
>>> On Sat, Aug 28, 2010 at 8:38 AM, dennis true <dennist3 at gmail.com> wrote:
>>> 
>>>> what about just using a bench grinder.......hehehehhee
>>>> 
>>>> 
>>>> On Aug 28, 2010, at 2:58 AM, raymanowen at gmail.com wrote:
>>>> 
>>>>>  1. "...use a hand drill / Vise to hold it and a hole saw to cut mine
>>>>>  out.
>>>>>  2. From now on I will do my own.
>>>>>                            [When you see something done by someone
>>>>>  experienced in doing it, the process always looks easy. Something
>>>> looks
>>>>>  simple like changing the engine or automatic transmission oil and
>>>> filter
>>>>>  when someone else does it-  or a flat tire? Looks easy when you see
>>>> it done.
>>>>>   Show of hands- How many people actually do their own maintenance on
>>>> a
>>>>>  regular basis?]
>>>>>  3. The chrome coating is real thin. the core is bronze I think.
>>>> [Bronze-
>>>>>  like the Temple bells in Thailand? Stupid Marketing always says
>>>> "Heavy
>>>>>  brass" or "Marine grade brass"] Their specific heat is lower than
>>>> that of
>>>>>  the water they don't touch...
>>>>>  4. Very easy to cut with a hole saw."
>>>>> 
>>>>> Maybe Not-
>>>>> Did you see the machinist using a Hole Saw or claw hammer?  He did Not.
>>>>> In order to do the machine work with precision, conserve tools and the
>>>> porta
>>>>> filter handle itself, the cutting tools and workpiece were firmly
>>>> mounted on
>>>>> the lathe.
>>>>> 
>>>>> If your friend did not fracture the porta filter handle between the two
>>>> jaws
>>>>> of the bench vise; did not break the pilot hole drill bit when the hole
>>>>> saw seized in the work piece, crack his wrist, yank the pf out of the
>>>> vise
>>>>> as it broke and busted the drill motor when it hit the floor, he's
>>>> either a
>>>>> Magician or extremely lucky.
>>>>> 
>>>>> Luck and Magic may be entertaining, but have no place in a machine shop
>>>> or
>>>>> on the highway. (When you feel inclined to buzz it over 100, are all
>>>> the lug
>>>>> nuts torqued, tire pressures and engine oil just right? Do you Know so
>>>> or
>>>>> just Hope so?)
>>>>> 
>>>>> Cutting out the entire bottom of a portafilter might seem easy with a
>>>> large
>>>>> hole saw, bench vise and hand drill, but it's not the all-pro move. It
>>>> will
>>>>> probably cost you some painful surgery, a hole saw, a hand drill, a
>>>> porta
>>>>> filter and some CSA points.
>>>>> 
>>>>> At Colo School of Mines Earth Mechanics Research Institute, I used a
>>>> 500-ton
>>>>> press and 12,000 psi triaxial pressure to test and chart record the
>>>> failure
>>>>> point of 2" OD X 4"L oil shale cores, up to 480° C, (Love PID
>>>> controller,
>>>>> type K s/s sheathed grounded junction thermocouples) and my strain gage
>>>> load
>>>>> cell.
>>>>> 
>>>>> According to an ME/ Chem E friend, "Some of the stronger bronzes need
>>>> full
>>>>> hydrodynamic (pressure) lubrication, or they gall and seize. (That's
>>>> what
>>>>> grabs and breaks the hole saw, your wrist, and yanks the pf out of the
>>>> vise
>>>>> if you had a good grip on the drill)
>>>>> 
>>>>> The heavily leaded bronzes survive much better when lubrication is
>>>> marginal,
>>>>> if speeds are Slow Enough. Ever seen a slow hand drill? Hammer
>>>> Mechanics
>>>>> usually run full-speed.
>>>>> 
>>>>> The opposing material and finish can make a big difference in the wear
>>>> rate
>>>>> and tendency to seize and gall. (Break your wrist)
>>>>> 
>>>>> Poor geometry usually can not be compensated for with "better" as-cast
>>>> or
>>>>> annealed materials." The tabs of 58mm pf handles each have to withstand
>>>>> almost 300 pounds in shear at 9 bar pressure. Things could go rong in a
>>>>> hurry if the shot stalls and the OPV doesn't bypass and relieve the
>>>> pump
>>>>> pressure, like my former Crapesso.
>>>>> 
>>>>> Don't even think of using type J thermocouples around moisture- the
>>>> couple
>>>>> is Iron/ Constantan. Guess which one corrodes like Hell and destroys
>>>> the
>>>>> junction?  Type K couple is Chrome-Nickel/ Aluminum-Nickel or Chromel/
>>>>> Alumel.(Was © Omega) The Chromel is a laboratory-grade Nichrome- the
>>>> heater
>>>>> wire in toasters- and can withstand ≤ 3000° F.  Alumel is a little
>>>> lower and
>>>>> type K is a stable Seebeck couple at 2700° F.
>>>>> 
>>>>> Cheers, Mabuhay -RayO, aka Opa!
>>>>> 
>>>>> Do what you always did, get what you always got- If you get back
>>>> without an
>>>>> ambulance ride or tow truck, maintenance was OK.
>>>>> _______________________________________________
>>>>> Homeroast mailing list
>>>>> Homeroast at host.sweetmariascoffee.com
>>>>> 
>>>> http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.com
>>>>> Homeroast community pictures -upload yours!) :
>>>> http://www.sweetmariascoffee.com/gallery/main.php?g2_itemId=7820
>>>> 
>>>> 
>>>> _______________________________________________
>>>> Homeroast mailing list
>>>> Homeroast at host.sweetmariascoffee.com
>>>> 
>>>> http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.com
>>>> Homeroast community pictures -upload yours!) :
>>>> http://www.sweetmariascoffee.com/gallery/main.php?g2_itemId=7820
>>>> 
>>> 
>>> 
>>> 
>>> --
>>> Ambassador for Specialty Coffee and palate reform.
>>> 
>> 
>> 
>> 
>> --
>> Ambassador for Specialty Coffee and palate reform.
>> 
> 
> 
> 
> -- 
> Ambassador for Specialty Coffee and palate reform.
> _______________________________________________
> Homeroast mailing list
> Homeroast at host.sweetmariascoffee.com
> http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.com
> Homeroast community pictures -upload yours!) : http://www.sweetmariascoffee.com/gallery/main.php?g2_itemId=7820



More information about the Homeroast mailing list