Cut flaps

To cut the flaps from CR80 PVC cards, they first need to be cut in half. You could probably do this with a paper guillotine, but I don't own one so I made a jig to score them with a utility knife and then snap them in half.

Start by putting 3 nails into a scrap piece of wood to hold the card in place:

Then, on either side of the working area, place a card or two (I used a PVC card plus a business card) to elevate a ruler which will be clamped in place as a straight edge for scoring.

Make sure the ruler is clamped exactly 1/2 card length away from the two top nails:

Then slide a blank card under the ruler and hold it tightly against the nails while scoring along the ruler edge.

You should get a nice clean line, which doesn't have to be too deep.

Bend the card away from the cut until it's folded back on itself, making sure that the ends of the card match up with each other (otherwise adjust the ruler alignment to correct for this). Then straighten the card and bend the opposite direction until it snaps in half.

Do this with 20 cards to get 40 half-cards. Then take each half-card and use the flap cutting jig to punch a notch out of each side.

The punched holes may not be completely clean (e.g. some material left outside the hole) but that's ok. Take some diagonal cutters to clip off the excess material and clean up the top/bottom of the punched notch.

If you're interested in more precise dimensions for the flaps and cutouts and the reasoning behind those values, see the discussion here: https://github.com/scottbez1/splitflap/issues/8

If you'd like to save yourself some time, an alternative to cutting your own flaps is to purchase pre-cut flaps that I've had professionally made, available on Tindie. Purchasing pre-cut flaps from me will also help fund the continued development of this open-source project.