I looked through some Turkish sites in regards to Taşdemir and what I've found out from translating (using Google Translate) and looking up in dictionaries is that it is a combination of words 'taş' which means "stone, rock, gem" and 'demir' which means "iron."
All of the websites that I've been to show the same meaning + the added connotation (at least, that's what I presume) which is "strong and healthy."
Here are links to dictionaries which show what these words mean:
https://en.wiktionary.org/wiki/ta%C5%9Fhttps://en.wiktionary.org/wiki/demirhttp://www.turkishdictionary.net/?word=ta%FEhttp://www.turkishdictionary.net/?word=demirhttp://tureng.com/search/ta%C5%9Fhttp://tureng.com/search/demir
I could be wrong but with all the websites that I've been to being Turkish, I would say that they are, at least, a bit credible with their information.
According to
http://www.ismininistatistikleri.com/tasdemir-6511, 85 males were named Taşdemir so it is quite a rare Turkish name.
Hope it helps. :)
My PNL:
http://www.behindthename.com/pnl/149249This message was edited 5/6/2015, 5:31 AM