This video.

For those of you who don’t know, Man At Arms is part of the Awe Me youtube channel, and their shtick is to produce their versions of weapons seen in popular entertainment, such as video game and movie weapons. In this case, close to the beginning of the video, the narrator claims that they’ll “be using only tools and techniques from the 19th century.” I’m a big fan of the Man At Arms series, but badhistory is badhistory, and as such, it should be called out.

So, the moment I saw what is most definitely an oxy-acetylene torch in the hands of one of the weapon smiths, my eyebrows rose.

According to Wikipedia:

French engineers Edmond Fouché and Charles Picard became the first to develop oxygen-acetylene welding in 1903.

Since oxy-acetylene welding itself was developed in the 20th century, I highly doubt that anyone would've used an oxy-acetylene torch for cutting in the 19th century. (Although you're free to correct me if I'm wrong about that) However, the smith goes on to reassure us that it’s still somehow legitimate, because a German inventor invented the first blowlamp in the 1790s. Well, it’s still flawed to compare an oxy-fuel oxy-acetylene (Edit: yeah, oxy-fuel torches can use liquid fuels too) cutting torch to these early blowlamps, because early blowlamps would use a liquid fuel and air instead of the gaseous acetylene fuel and pure oxygen used by an oxy-acetylene torch, which reaches much higher temperatures on combustion and requires more advanced technology.

(Edit: as /u/Feragorn mentioned, the smith also claimed that he wouldn't use belt sanders or grinding wheels, although both of them are 19th century tech too.)