Thanks for sharing your experience, very similar to mine. My IBM Selectric II has buckling springs, but the ball/strike isn't fast enough to keep up with my ty

Thanks for sharing your experience, very similar to mine. My IBM Selectric II has buckling springs, but the ball/strike isn't fast enough to keep up with my typing... so the keys don't get abused nearly as much (never had a keyspring break on this typewriter). My honest assessment of Unicomp's newer buckling springs: you need to use a more-durable metal [see 80's/90's versions, for comparison). The springs seems to fail more from fatique than force... which is almost-certainly a materials science deficiency.