The conversions between thread, twine, and rope are out of whack. It's essentially a duplication exploit. This mod looks promising, but this is very rough as it stands.

Observation:
1 rope >> 8 full spools of twine (5 units each spool).
12 units twine (2 and 2/5 full spool of twine) >> 1 rope
meaning, exploit gain of 5 and 3/5 spools of twine in one round of back and forth conversion

1 full spool of thread (10 units) >> 1 full spool of twine (5 units)
1 unit of twine (1/5 full spool of twine) >> 2 full spools of thread (10 units each)
meaning, exploit gain of 9 spools of thread in one round of back and forth conversion

I suggest adjusting the conversions so that no gains in quantity happen in conversion and reverting back. I would even suggest at least a bit of penalty for converting upwards from thread.

For an example of straight conversion, 20 units thread (2 full spools) >> 5 units twine (1 full spool), 5 units twine >> 20 units thread, and 40 units twine (8 full spools) >> 1 rope, 1 rope>> 40 units twine

For an example with conversion penalty, 20 units thread >> 5 units twine, but 5 units twine >> 10 units thread.