@VRSilver, welcome to CT! Well, you've received some excellent responses on how to "straighten" a bent coin, & the example that @GDJMSP showed is an incredible & successful example of a "necessity". But from a lay persons point of view, why would you want to straighten it? (On the other hand, I can see exactly why a lay person would want to do it.) It's not that egregious & "straightening" it is not going to increase it's value. There are some who collect (read: save) coins such as this just because of their uniqueness, and the evidence of the rough "life" they have led (whether or not we know provenance or the reason for the "deformity"). It is, after all, a 454 yr old coin which appears to have served its "possessors" well. Your comment... ...while it may apply to you, many of us don't hold the same sentiment. That's the beauty of this hobby...to each his own. I only comment about this because any "lay persons" or "newbies" who may be reading this thread may have the impression that it's not OK to have a coin that's a little "off", & that it's OK to "fix" every little thing. Please don't take this as criticism; there are some great responses here. And again, welcome to CT! JMO
Only thing I would add here is the "work hardening" tendency of copper and copper alloys. Once bent, copper tends to work harden and resist bending in the opposite direction. Be careful with these.
Thanks for the input.. As stated above, this is mainly just thought exercise. But yea -PlanoSteve-, it does kinda make me feel bad to look at it. Not because of wanting everything shiny and perfect, but I just kinda feel sorry for it in a way. It's an interesting take on it to look at it in terms of being a wounded warrior tho.. By lay-person, I more-so meant is there anything a non-professional could do in such a situation ? It's a 20-30 dollar coin.. I've been a collector for over 30 years so not asking as a beginner. Vice with leather cushion sounds most reasonable if i should try. Seems like the equal pressure rather than a blunt shock would be the right road. Sir Knight shall probably stay as he is tho so don't worry.
Depends on the metal, Iron alloys you heat a quench to harden or allow to cool slowly to anneal. Gold acts differently you heat and quench to anneal. On the OP coin I would also do a little research first to see how this coin was made. Some of these early coins were produced on a roller press as they came out of the press with a bend to them. Make sure you aren't straightening a coin that is SUPPOSED to be bent.
As others have pointed out, it is different for different metals -- I didn't realize how different. I'd take the author's word over mine, although I'd prefer to do more research before taking either word.
this is tougher than it looks at face value. You'd need to bend it back past it's straight point, in the exact same spot, trying to "flatten it" out with pressure it will spring back to a slight bend when the pressure is released, and bending it in the wrong spot will make it even more bent. it's silver. might be worth taking it to a jeweler/jewelry maker to straighten it than to DIY it. if anyone can't straighten it and make it look like it wasn't bent afterwards, it's would be a jewelry maker that works with silver and stuff that gets bent I'd think.
For those who don't know or are unfamiliar with the roller dies mentioned, this is what they look like -