Well not sure what they are for????? soldering irons? well kind of not on the list anymore, the copper based soldering irons are pretty well perfected by time these were made. also the handle you need to keep pressure on the tab so it stays in no latch, so no hammering. My guess on age is 1900-30's. So one could only use one at a time or did they stick them in do something else? pull them out repeat till done? quick to release and change.
Could they be for working wax in a lost wax process of casting? lots of foundries in this area back in the day, think I got some other sand casting tools slickening spoons at that auction about 30 years ago!
Could they be used with heat activated glue? horsehide glue was common then.
last idea is some type of fabric iron? heated to set the pattern when starch was used pleating irons were common, I've only been thru 5 pages of what is it's and there was one in it.
They are spending some quality time in a tub of oxalic acid to remove the rust, maybe that will help see a maker's mark.
