Question: How so I cut up a long strip of leather from the 45 cm diameter leather disc ?
Option 0: With a cheese cutter, cut a 1 cm strip from the outer rim of the disc and continue by turning the disc, continue until the diameter is too small for the  cheese cutter.
Option 1: With a leather strap cutter, cut a 1 cm strip from the outer rim of the disc and continue by turning the disc, continue until the diameter is too small for the  strap cutter.
Answer: 1