“A twelve dent reed is good for 2/8 cotton (also 2/8 cottolin, a blend of cotton & linen) at 24 ends per inch for a twill weave- 2 threads go into a slot. ( When you take out some of the magazines with patterns, you will see some of the instructions will have various threads at so many ends per inch, so a 12 is a good basic size to have.) Because reeds are so expensive, you might want to try rust remover and wire brushes- between skipping and doubling or tripling threads in the dent, you could have 6 or 12 or 18 or 24 or 36, or even 20 with a couple of single threads spaced out er inch and the rest doubled……)“For rugs, I tend to use 5/8 linen which works at 6 ends per inch, ( you could use every second dent in your twelve but if you have thicker yarns, there might be some abrasion?). I just checked my reeds, I also have a 5 dent and an 8 dent, but I think I use my 6 dent a lot. I also got a metric one that works out to 7.5 ends per inch, which I think I have used for wool blankets, but an 8 would do. I use the metric one because I got it with my loom.
“If you order a higher (4 inch) reed, be sure your top of you beater will move up to accomodate the height. there may be holes or slots for the top of the beater joining it to the struts (??) at the side of the beater. the slots would allow different heights of reeds, the holes might not. I think I ran into that problem on one of the older table looms- I wanted to use a new 10 dent reed on it and it wouldn’t fit…. You might be able to drill a new pair of holes though, I am trying to visualize it.- as long as it isn’t too close to the old ones that it would weaken the wood, I would think.”