The Creation of a Turret Clock

No problem with the saw...

  I can breath a sigh of relief.  The use of hacksaws in period is documentable.  I use a hacksaw on both the gears and the corner posts.  Recent information came to me that hacksaws weren't in use until 18th century.  That definitely appears to be incorrect.

  The Mastermyr Find(9th century Viking blacksmith toolbox) definitely contains a hacksaw.  The hacksaw has all of the makings of being a metal cutting hacksaw.  First, the shape of the teeth matches a modern metal cutting saw.  Also, in the same find were several axes and adzs.  These were made of wrought iron with a hardened steel for a cutting edge.  The steel's carbon content is 0.4%.  This is about the minimum carbon steel can have and be hard enough for tool work.  As a matter of fact, after checking my other materials at home, 0.4% is when steel suddenly gets to stage where water quenching it can harden it.  Unfortunately, my new book did not analyze the steel in the hacksaw.

  Another interesting item in the find was a piece of antler.  Some might immediately think of a decorative use of the antler but this was in a blacksmith's toolbox and blacksmiths have another use for antler.  If you take a piece of iron and surround with organic material such as ground bone or antler, then take it to critical heat for a length of time, the iron will become case hardened.  What that means is that some of the carbon from organic material actual enters the iron, increasing its quality as a steel.  Case hardening has one major drawback, the amount of penetration of the carbon is usually somewhat minimal but a depth of 1/32" is fairly easy to achieve.  With the hacksaw blade, this is okay.  Since the blade is so thin, the carbon could penetrate from both sides, possibly all the way to the interior.

  Whew, one less thing to worry about.  Oh, and here is a drawing of the hacksaw.  Click if you want to examine in detail.