Most 335 machines have around 15 mm of foot lift. And can sew 6mm thick any thicker and they don't feed due to the walking feet only raise so far while lowered in to sewing position or that's what the spec. On the Yamata fy335a that's what I have I got mine for lighter weight leather . Like wallets and hand bags. I use a Tipman boss for holsters it will sew 3/4 inch thick leather but it's manual not powered by electric. There are machines that will sew heavy-duty items but they are pricey. Cobra makes a nice machine for holsters that's electric. I'm new to the 335 myself but have done leather work for 30 years.