Apparatuses and methods for cutting porous substrates

An apparatus for cutting a sample piece, having a shape and an outer dimension, out of a porous substrate, comprising:

• a puncher having an outermost dimension at a punch head;
• a stripping sleeve comprising one or more channels configured to receive one or more guides;
• a die having an innermost dimension that is larger than the outermost dimension of the punch head;
• and
• a c-frame fixture that holds the die in a fixed position relative to the puncher and stripping sleeve, wherein the punch head is configured to pass through the die and a bottom of the c-frame fixture in a fully extended position;
• a support coupled to the c-frame fixture;
• a roller ball cage positioned coaxially within the c-frame fixture;
• a pillar positioned coaxially within the roller ball cage and positioned about the stripping sleeve;
• one or more guides coupled to the pillar and corresponding to the one or more channels wherein the one or more guides are configured to change position within the one or more channels when the stripping sleeve moves relative to the pillar and wherein the one or more guides comprise a head portion that is received in the one or more channels and a notch portion that engages with a retaining element to retain the one or more guides on the pillar, wherein the notch portion is wider than the head portion such that the notch portion forms a flange extending from the head portion;
• and
• a spring positioned on an interior of the pillar and the stripping sleeve and about the puncher.