Caring for your Espresso Machine Shower Diffuser Screw


For the most part maintenance on a traditional espresso machine can be relatively inexpensive, but then there’s that little espresso screw that could cost you hundreds of extra dollars. The espresso screw I am referring to is the one used to hold your espresso machine's brew group shower screen, diffuser, and/or shower plate in place. This screw if improperly fastened or tightened, can cause the threads that hold the screw in place to weaken. Usually through time, these weakened threads will cause the  screw to fit loosely. Eventually, the screw, screen and diffuser will no longer secure into place causing the brew group to be inoperable. For the espresso business owner, this is a small catastrophe brought on usually by either thermal expansion or by just using the wrong screw. 

Espresso Brew Group with Stripped ThreadsRemember Metal Expands and Contracts
Thermal expansion is a term used to refer to the expansion of metal when its temperature increases.  Typically, at the end of the day, group parts are cleaned and then placed back up into the espresso machine’s group. Once in place, the temperature of the espresso machine will cause the diffuser plate to heat and then expand. As the diffuser plate becomes fractionally larger, it slowly places tension on an already tightened screw, subsequently weakening the threads. The amount of force needed to secure your screw is something to educate yourself on. 

Know How Much Torque Your Need

Every brew group and its parts are made from different grades and types of metals. New Brew Group HoleThose metals will dictate how much your parts will expand and change when the temperature increases. You’ll need your parts secure so how do you know how much torque is needed for your screw? Your machine manufacturer will have a recommendation on how they suggest you secure your group screw.  You can also ask your service technician.  They are your best and most valuable resource in keeping your equipment operating efficiently. The other most common cause for weakened threads happens when the wrong screw is used.  

Your Local Equipment Retailer will have Spare Screws On-Hand

If you lose your screw, and it’s really easy to do, you cannot operate your group. For most, the temptation to run to their Variety of Screwslocal hardware store is typically overwhelmingly. Unlike the country in which your machine was most likely manufactured, the U.S. does not use the metric system. You cannot use a standard screw in place of a metric screw. You might find some metric screws at your local hardware store and you may even find a screw that will work, but most likely it will either be in the wrong metal, which will affect the taste of your coffee, too short, which will weaken your threads, too long, which will not secure your parts, or the head will be in the wrong shape, which will damage your screens. To avoid even considering this costly mistake you should always keep spare screws, as well as screens, on-hand for a quick fix when parts go missing.  If for some reason you run out of extra parts, contact your espresso equipment retailer. Most likely they will have extra on-hand for your exact situation.



Providing on-going Education is a Good Strategy

Depending on your machine, the cost to repair stripped threads can be surprisingly high. If you are unfortunate to have your screw hole as a section of your group, you’ll end up needing to replace the whole group. The price tag to replace an espresso machine’s group can run anywhere between a few hundred to several hundred dollars.  Hopefully, when you purchased your espresso machine, you received training in its features, maintenance and operation, but equipment education should not stop there. As your staff changes and matures, make sure to work with your local service provider to re-train staff on your equipment’s operating procedures. You’ll undoubtedly save money and your team will be happy to know that they are competent when operating your equipment.  Need to locate a sales and service company in your area? You can find one right here:

Tech Nick Lee Ahero

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