You can buy 3/8 inch leather treadle belting off of Ebay it even comes with the connecting hook. The seller I bought most of my industrial stuff from was from New York. I'll find his name for you. I had a 31-15 and liked it but I could never get it to run perfectly smooth. There was a catch somewhere in the upper shaft. I tried everything to work it loose. It was a really abused machine that had sat in a damp barn for a number of years. It took me weeks to get the crud out of it. I finally gave up on Q-Tips and gentle cleaning and took it to the car wash and used the pressure wash hose on it without squeezing the trigger. You should have seen the black gunk and crud that came out of it - there was even straw inside it! It was a fun machine to use ans did sew a pretty straight stitch. I eventually sold it. I believe I have a lot of needles of all sizes for it here somewhere; if you are interested I'll make you a good deal on them or maybe a trade.