About using the tubing instead of leather for the treadle belts. I haven't tried the tubing, but even the leather will stretch and have to be adjusted at least once after you start using your treadles. The one thing I learned after using several treadles all the time, is to not tighten the belt too much! Also, make sure there is no sewing machine oil in the treadle grove. I wipe the grove out after I oil the machines just to make sure there is no oil residue in that grove.
On a happy note, I bought a Viking 6010 yesterday. This is my first Swedish machine so I am excited about it! It was running when the lady last plugged it in, but it is frozen now! I will see if I can get it running. Supposedly, this machine is from the late 60's so it will be fun. I usually don't work on machines that new - except FW's of course!
I may need help when I get the time to dig into this machine. I hope I can get it to run!
Nancy