Apparatuses and methods for cutting porous substrates

1. 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.

2. The apparatus of claim 1 , wherein the stripping sleeve has a stripping head that corresponds to the shape and outer dimension of the punch head.

3. The apparatus of claim 1 , wherein the stripping sleeve is spring loaded.

4. The apparatus of claim 1 , wherein the punch head has a length and the one or more channels have a length that corresponds to the punch head length.

5. The apparatus of claim 1 , wherein the puncher is coaxially located within the stripping sleeve and the puncher has a path axis along which the puncher moves within the stripping sleeve.

6. The apparatus of claim 5 , wherein the stripping sleeve is spring-loaded and has a shoulder against which the spring presses.

7. The apparatus of claim 6 , wherein the spring is coaxially located between an inner surface of the sleeve and an outer surface of the puncher.

8. The apparatus of claim 1 , wherein the pillar and puncher are removeable from the fixture by disengaging the engaging components.

9. The apparatus of claim 8 , wherein at least one of the engaging components comprises a set screw.

10. The apparatus of claim 1 , wherein the spring is in direct contact with the puncher within the pillar, and wherein there is a gap between the spring and the puncher within the stripping sleeve.