Swag, years ago in our more adventurous lives, Mrs Carp and I set about making tallow candles. On the first attempt, we cut up the suet as small as possible. It was still an onerous task to get that stuff rendered.
Take Two: the second butcher we went to asked us what we wanted the beef fat for, thinking we were making bird feeders. When we told him and explained how difficult it was, he told us he would _grind_ it for us for free.
D'oh! The second round went much easier, though the cracklings were like tiny gravel.
Hand-driven meat grinders can be found at any decent flea market and occasionally at thrift stores. I have two or maybe three in my cupboard (along with 5 manual pasta machines --don't ask
). They are also for sale at large sporting goods stores like Cabellas, Bass Pro Shoppes, Field and Stream Stores, etc, in the hunting/smoking/game processing gear sections.