IF I remember , the #1 takes a flat belt, same as used on old metal lathes, ect... you would need a lenght , Not real sure who you could find to make one... I do have a belt driven lathe , but as of yet have never had to find a new belt, I do know aguy here that has made his belts, I can tell you they are flat leather , the ends are both cut on a very very long taper, I mean very long taper, Then glued together ,, then smoothed a sin sanded smoother. so maybe a she repair plce could glue it for you .. Th ehorse supp;y would have the belting strap or tandy leather would also, tandy could steer you in the right direction the having a belt made ??
BUT, the needles for a #1 are curved,, if you don't have needles weeeell , again thats if IRC