everyone here has given you the right information, it is best to start with the correct equiptment to make quality products.
but i used a 1949 singer 15-91 for many years and sewed deer ,buffalo, elkhide and up to 20 ounces veg. tanned cowhide for holsters with problems? yes but i did it.
i actually sold things for several years and had numerous return buyers.
did i do it the right way. nnnnnnnnnoooooooooo
had to fix the timing several times and replaced the motor once and hand wheeled the machine more times than i want to remember but i only paid $49.95 for the machine, but it worked.and got me started as i had never used a sewing machine before.
i have had a new cobra 4 for about a month now and i can finally be somewhat proud of my stitching and the items i make and have not come close to learning how to use the machine correctly or efficiently.
if it will get you started, buy a $50.00 machine and make something before you spend $1000.00 or more and decide working with leather is something you do not want to do.
baby steps first?????????
or jump in with both feet but you will have fun either way .
i did
ron