Shore A hardness explained
Every reference in our catalogue gives its hardness in Shore A (Sh A). It is the most useful single number to choose a rubber part: it tells you how much it gives under pressure.
What it measures
A durometer presses a small indenter into the rubber; the scale runs from 0 (very soft) to 100 (very hard). A rubber band is around 30–40 Shore A, a car tyre tread around 60–70, a shoe heel around 80–90.
Which hardness for which part
40–50 Sh A: soft. Seals well on uneven or fragile surfaces with little clamping force; good vibration isolation under light loads.
60–70 Sh A: the everyday range for gaskets, washers and pads — a balance of sealing, strength and durability.
75–90 Sh A: firm. Carries heavy loads and pressures without extruding; used for supports, spacers and wear parts.
Hardness and cutting
Soft, thick rubber moves under the blade, so very small details are harder to hold in soft grades. For small, precise parts a firmer grade or a thinner sheet helps.