I have had a lot of broken threads on this warp so far. Far more than I would expect. I think it might be the age of the yarn. I think this yarn might be quite old.
Here is a box of yarn that came with the loom:
And here is what the yarn inside looks like:
I haven't used any from this box, but I have used several partially-used spools that came with the loom. Which means the yarn I put on the loom is at least 40 years old. I'm not sure I want to use the stuff in the box, if this is any indication of what to expect. I often use old yarn, I have a lot from the 80's and even a few cones from the 70's, but this yarn is 60's or earlier. Maybe that's the limit for cotton? My older yarns are all wool or linen, and seem to have held up well.
Maysville carpet warp is still made today. The Maysville Guild doesn't exist anymore, as far as I know. They had a newsletter and encouraged members to send in pictures of themselves and their work. Membership was free. I'm not sure where to find the old newsletters, perhaps some are online somewhere.