using calipers as scribes?

[Crusty]

If you're cutting to a scribed line then thousandths precision shouldn't be expected so tip wear of a cheap caliper puts the error in the acceptable range for a scribed line.

A caliper is really just an approximater anyway and if greater precision is required then a different measuring device is needed.

I regularly wear out end mills costing in the same ball park as cheap calipers and with no cutter grinder to resharpen them that's a fact of life that I understand and accept going in. For that matter everything in a machine shop is doomed eventually.