I use them all the time. the first one a buddy gave me, it had a cracked down leg below the pivot. i took it to work and nickle welded it and then hammered the red hot weld with a facing hammer that pitted the weld. I can't find it anymore it blended in so good.
the second one was found about 20 years ago in a loader bucket while cleaning an old horse barn. they gave it to me for fixing machines for them.
the one I need to find is like my grand pa's. he had it for years. my uncle left it with the house when it went.
not sure on what kind it is. it may be a Parker. this pic is from the early `50s the table saw was hand made. I have his disc sander that he made out of a washing machine motor.