Since nobody else answered, I'll venture ahead here. Decades ago, I had a NH 9ft. haybine. The whole sickle bar assembly pulled out the side, as I remember, and I don't remember which side. I would spray the sickle bar with WD40 often, since I kept it in an open shed roof, and everything got a little wet from fog and general humidity in Georgia. When you pull it out, or slide it back in and you hear one of the knives hitting metal, that's one of the guards that got bent from a rock, and will need to be bent back or replaced.
I used to replace the teeth, but that was before these little metal disk grinders were so popular and lightweight. I'd be tempted to try a quick touch-up with the sickle bar off using a disc grinder. You will lose some of those little serrations that help cut the crop, though. Riveting a 9 foot bar took some time, but other guys had a complete spare bar ready to go and were down about 5 minutes when one broke. I remember that the guards distance from the blade was critical, especially in thick bermuda. If you find a streak of badly cut material behind you, (and you can somehow see it through the crop), stop and look at which blade it might be.....could be the guard spacing, too.
I also remember that there was an optimum speed according to conditions. Too fast, and you clog or miss some. I ran just a little under 540 rpm and tried to lift if I saw a fire ant hill, since they really round out the knives.
