Ring compressor

I have a coupla any size Springsteel jobbies.
The "good one" either Mac or S/on I inherited used with the business, very old, but works good, lasted about 60 years, dozens of engines, all sizes, and been the "shop-tool" for over a dozen mechanics.
It needed "tuning" a few times.
The similar kind, I bought for home use, but wouldn't " tune ", - became a frisbee across the yard one night.