I added a cast iron Boss to my machinery, a bottom fed Singer 45 and a Juki 563, and I have sewn a pile of leather on it. A couple of years ago I stumbled on an Adler 205-374 with a Rotan Quick Stop motor with a needle positioning device, and it made my day!. From that day my Boss has been idle, collecting dust. I have been thinking of selling it, but it will be a tough separation. Before I found the cast iron Boss I have had two Aluminium Boss machines ( IMHO junk) , both of them broke down several times, a lot of trouble and spent time. To be true, I don´t think you really need it