ER40 precision spring collets are available in a wide range of popular sizes up to 25,4mm (1″) diameter. In the wood industry, this collet style is usually found on Biesse machines and some Busellato machines. Collets are consumable items, in that they wear out with use. Replacement is a routine maintenance task that should be completed approximately every 500 machine hours. Failure to do so will result in less than optimum tool life and can reflect in the finish of the material being machined.