How to Make Inexpensive Cards for Tablet Weaving

I made a large stack of cards for tablet weaving.  By supplying some labour, I got cards at a lower cost than buying pre-made cards from a weaving supply shop.

I took some decks of playing cards, the oversized kind, and with a paper cutter I trimmed an end off of each card to make each square.  I rounded the corners with scissors.  On the advice of a relative, I went to a printing shop and had the holes cut.  I supplied the shop with a store-bought card for reference and I also made a template since the playing cards were larger.  To make the template, I drew circles on one playing card by laying the store-bought card over top, matching its corner with the corner underneath, tracing inside the hole, then repeating this by moving the store-bought card to each corner.

If I'd used a hole punch, some of the holes would be misaligned and I would have gotten discouraged from the tediousness of the task.  My dad tried using a drill press on a small stack of trimmings but the holes came out ragged.

Now I have enough cards to warp all one dozen of the Old Believer cloth beams my dad made.