A few years back, I came across a hefty, all-metal, compact (at least for back then) Sunbeam jigsaw in great condition except for the power cord which I replaced with an almost exact duplicate. Works great but I don't use it. My Bosch VS barrel grip jigsaw is far superior. So, it's a workshop queen for the most part. Sold a circa 1969 all-metal Rockwell 1/2 sheet sander a few years back only to turn around a few months later and buy its reincarnated successor, i.e. a new Porter Cable 1/2 sheet sander. There is, however, a difference in the actual performance as the newer PC is a bit quieter and also a bit smoother running.
Don't force it. Use a bigger hammer.