You probably don't have any nitric acid around. But,if you did,file a clean spot on a vise,and apply a drop of nitric acid. If it is wrought iron,the spot will turn gray. If mild steel,brown.
I can generally tell wrought iron just from looking carefully all over the surfaces. Wrought iron has silicon inclusions in it,which can be seen as black lines here and there in the metal. Mild steel will not have these inclusions.
Be careful how hard you clamp work in one of those vises,as the screw threads are badly worn on one of them. You might have the threads jumping the nut,or possibly strip out the threads that are inside the hole. They were probably brazed in as I described. They look like they are starting to come loose and out of the hole in 1 picture.
The 5th picture down shows a "crack" in the bulged part of the body where the screw goes through. That could be a silicon inclusion,or a "cold shut" from being forged,where the metal did not weld when it was forced together. Maybe that's the crack you refer to. Nothing to worry about.
Those vises were never,ever made of cast iron. Only from wrought iron or later,mild steel. You cannot forge cast iron. The sellers are ignorant.
There are some other tests for wrought iron,but most require destroying a piece,or grinding. Wrought iron has no carbon. It throws long sparks with few branches. Grind a piece of KNOWN mild steel for comparison.
Those vises have been used very hard,and abused,it looks like. Just beware to not strip those worn screws out by tightening too hard.
They are 19th or early 20th. C. 18th. C. types have a different(and inferior) way of clamping to the log or bench they were meant to be mounted on.
Thanks very much George,
glad to hear those cracks are nothing to worry about, there are a few in the same area on the other side.
The threads on one are very narrow compared to the other two. That one has the thread coming off in the picture. Is that narrow because of the wearing of the threads?
do you know what the #'s mean on underside on mount plate?
That same vice, columbian brand, has a really deeply beaten vice tops as seen in the photo.
The last two photo's are of the no name vice , has a #8 on underside of vice body under the jaws.
It is also the tightest, and smoothest of them all.
It had some grease still on the screw. The last photo showing the vice jaws, you can see the lighter portion of the jaws. Is that a Hardened piece of steel at last part of jaw face?
Is there anything I can use to help clean the rust off with a hand wife brush?
Do I need to clean off all grease and replace with neversieze For the 1800degree limit, or something else when using for forging?
Out of the three, which one appears to you as being better made or in better condition for actually using it for holding items out of the forge?
The one with no name is the one in the last two pictures, that is the heaviest, and works much better, screw and receiver do not get loose and move around when opening the vise.
Thank you in advance for helping me sort these out, I bought 3 so I would end up hopefully with one good one.
Thanks again,
Jon