A number of years ago I came upon a Singer 31-15 at a garage sale. This machine is industrial size and was used in dressmaker factories with a motor that was able to stitch 2200 stitches per minute. Since all I had and used were treadles, that motor had to go. I found the parts I needed and excitedly converted it to a treadle. Because it is an industrial size machine the arm on it is extra long so it has more room to fit a quilt under it while quilting.
I was, however, having some trouble with the tension after awhile. I finally figured out that the bobbin casing tension screw would back out on its own and the tension would be really messed up. Now that I know that I can check and tighten it each time I change a bobbin. I wanted to tear my hair out about it before I finally realized what was happening.
Nice even stitches again 🙂