I have "designed" and have manufactured (for me) a custom fitting to take the place of the M6 x 8 allen-head screw found on E61 groupheads. I have termed this fitting the "Thermocouple Adaptor", but it is also a "Thermometer Adaptor". The adaptor for E-61 machines is available only in stainless steel and will accept ONLY a 1/8" thermocouple (of your choice) or the modified digital thermometer I offer. It replaces the M6 allen-head screw by screwing into the grouphead and sealing with a copper washer exactly as the existing M6 screw in your grouphead. The 1/8" thermocouple or digital thermometer stem is sealed to the adaptor by means of replaceable nylon ferrules. No drilling, tapping, soldering, brazing, cutting, teflon tape, or epoxy are required. Installation instructions for the adaptor can be found on my FTP "website" in the file entitled "DigThermAdptr7.pdf": http://users.rcn.com/erics/. Click on the file and save it to your computer. Please read these files carefully as they are designed to answer most questions concerning installation and use and even include a "quickie" install pictorial in the beginning. You might also want to read the file entitled http://users.rcn.com/erics/Digital%20Th ... 0Build.pdf as it gives a pretty good pictorial of the build process of the thermometer kit - if I do say so myself

The thermocouple/thermometer adaptor kit consists of the adaptor with copper washer, a spare copper washer, a spare nylon ferrule set, and a plug to seal the adaptor should you wish to or need to suspend temperature measurements. After inserting your thermocouple and attaching it to your appropriate meter, you can easily observe and/or record brew and/or flush water temperatures approximately 1.25" upstream of the espresso puck/empty basket using your normal espresso brewing/flushing practice. EQUALLY IMPORTANT, you will be measuring a temperature that is very representative of the overall grouphead temperature.
OK, I want one, what do I do now? - Read the installation instructions, then read the installation instructions and finally read the installation instructions again appropriate for the adaptor kit you desire. Complete ordering, inventory, and pricing information can be found on my FTP site in the document entitled "Pricing_Inventory_Ordering". You need to be somewhat mechanically inclined and understand the use of thermocouples and appropriate temperature meters OR have a good friend who is. The adaptor kit prices which include shipping via USPS 1st Class are: E-61 Thermocouple Adaptor - $74, Digital Thermometer Adaptor Kit with user switchable degrees F/degrees C - $106.00. Shipping outside of the US via USPS Priority Mail (small flat rate box - partially trackable) is $40 additional. Paypal is accepted and is the preferred method of payment as described in the Pricing_Inventory_Ordering pdf document available here: http://users.rcn.com/erics/ .
COMMENTS/SUGGESTIONS on the instructions or questions of a general nature that could be included in the FAQ section of the install manuals would be GREATLY appreciated. Thus far, a total of Three thousand Seven Hundred and Sixty-Three (3763) thermocouple adaptors and digital thermometer adaptors have been shipped to users of varying ability in 42 countries which include Australia (83), Austria (4), Belgium (4), Brazil (1), Canada (87), Chile (1), Czech Republic (17), Denmark (23), Dubai (1), England (38), Estonia (1), Finland (11), France (4), Germany (11), Greece (1), Guam (1), Hong Kong (7), Ireland (2), Israel (8), Italy (3), Japan (2), Korea (1), Malaysia (1), Mexico (1), Netherlands (69), New Zealand (17), Norway (7), Pakistan (1), Philippines (3), Poland (11), Puerto Rico (1), Romania (16), Russia (27), Saudi Arabia (2), Singapore (7), South Africa (2), Spain (2), Sweden (11), Switzerland (2), Thailand (1), Ukraine (3) and, of course, the United States (3242).
Stock Status: Digital Thermometer Adaptor Kit in F/C - 23, however replacement thermometers are always available. (calibrated exchange service).
THE 3000th ADAPTOR WAS SHIPPED TO CANADA
It is always best to check stock status BEFORE you place an order as this post is, maybe, edited on a monthly basis. Edited 01/14/2021 to reflect improved text, adaptors shipped, and current stock status. Thermometer construction has been vastly improved. New thermometers are assembled without the use of any hot melt glue as the thermistor wiring (and thus the thermistor itself) is held in place with a wedged small aluminum tapered tack. The lower housing of the thermometer has been machined slightly to allow for much easier assembly or user repair and the latest units include soft-touch buttons and auto-shutoff to extend battery life. The depth adjustment is no longer necessary as the depth is now fixed at the proper dimension with the newly designed probe housing. All improvements are easily retrofittable.
Acknowledgements:
Thanks to Andy S. for suggesting I go with an E61 adaptor vice just one for Silvia after my original post on AC and to Sean L. for suggesting nylon ferrules and to Greg S., Sean S., and Dave S. for devising all sorts of innovative methods of measuring brew water temps. I also thank Lino V. for his unselfish OK to use several of his E61 group drawings contained in the thermocouple adaptor, digital thermometer, and adaptor tidbits documents.
The original posting in March of 2006 was cross-posted in its entirety to AC and CG.
Eric S.
erics@erols.com