What the disc conversion does

Eureka’s automatic tampers press with a fixed, repeatable force onto a flat disc. The disc diameter has to suit the basket it presses into: too small and a ring of loose grounds is left around the edge, too large and it binds against the basket wall. Since the tamper itself is unchanged, swapping the disc is the only thing needed when you change machines, change baskets, or run more than one portafilter size behind the bar.

The standard configuration on Eureka’s automatic tampers is a 58 mm disc. The other four diameters are sold separately as these conversion kits.

Choosing the right diameter

Work from the basket, not the portafilter. A 54 mm portafilter does not take a 54 mm tamper, and a 58 mm portafilter does not always take a 58 mm one. Measure the internal diameter of the basket with a caliper about 1 to 2 cm below the rim, where the wall is straight, then choose a disc roughly 0.2 to 0.3 mm under that figure.

As a rough starting point: 58.3 mm suits the wider precision baskets (IMS, VST and similar) used in 58 mm portafilters, where a standard 58 mm disc leaves a visible gap. 53 mm is the usual choice for Sage and Breville 54 mm portafilters, whose baskets measure closer to 53.7 mm inside. 54.3 mm and 57.3 mm cover baskets that fall between the common sizes. If you are between two figures, measure before ordering rather than guessing.

Which Eureka tampers it fits

Eureka lists the tamper kits per model, so the disc for a DISKO is not the same part as the disc for a Mignon Automatic Tamper or for the under-the-grinder tamper fitted to Atom grinders. All three lines offer the same four diameters. Choose the kit that matches your tamper, and if you are unsure which one you have, get in touch before ordering.

Specifications