Judging by the number of these for sale online, they're common, but there is not much information about them.
Wikipedia says Semi-steel casting is an old marketing term for a method of casting iron that is cheaper to make than a steel casting.
Other definitions are more specific, it's cast iron with steel scrap thrown in the mix.
It could be that these are just a cheap generic C clamp that no one felt proud enough to put their name on!
I had a couple of Lead-Steel clamps once. They were 4" new and 6" after a few uses. Adjusted automatically:)
ReplyDeleteSemi-steel is more ductile than cast iron, so I think that would be a good thing in a C-clamp. So I think that "semi-steel" was a positive marketing term in this case rather than one that denotes cheapness.
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