When did machine construction go wrong?

One of the regulars sent me this photo of a 40″ bandsaw from a website dedicated to old woodworking machines, called www.owwm.com

Old 1890's Cast Iron Bandsaw

Old 1890's Cast Iron Bandsaw

The gentleman in the photo found this bandsaw in the States on eBay – no idea what he paid for it.  The bandsaw itself is from the 1850s – 1890s, and it is 40″ (the wheel diameter), which gives it a massive throat, and it has a significant resaw capacity.  The thing looks like it weights a ton (and that may not be that far from the truth!), being solid cast iron.

I started scanning through the large collection of other bandsaw photos on the site, just out of interest, and noting the dates I started to see a trend emerge.  The newer the bandsaw, the more likely it was that it was folded steel construction than cast iron (and sure, other aspects such as guarding began making an appearance!)

So the question began to form – when did machine construction go ‘wrong’?  When did cast iron stop being the material of choice?

I’m not necessarily proposing that modern, folded metal construction cannot make a good machine, and the cost difference is phenomenal. Cast Iron also has a bit of a bad rap – when done poorly (in modern, cheap productions particularly, when cast iron is used incorrectly in thin casting as a cost-saving measure, using poor material engineering techniques then it is a curse – castings break easily (cast iron is by its nature brittle, unless correctly heat treated to produce versions such as spheroidal cast iron), but it is still a superb material of choice in many situations.

It’s weight can be a significant benefit, particularly for machine stability, it can be easily machined (but leave welding it to the experts – low carbon steel (mild steel) is easily welded, high carbon steel is not, and needs serious welding procedures written to cope with it.  Cast Iron can be thought of as high carbon steel, with so much carbon added that it becomes a bit of a carbon/cementite/iron mix.  Welding it is a bitch!)

Because of the (micro) voids of graphite in the cast, cast iron has real vibration damping capabilites – an excellent property for a machine to have – reduced vibrations means a smoother running machine and less noise.

Finally, strength – put a heavy cast iron body against one made from folded steel – one has inherent strength from the material, the other from careful design and internal ribs trying to dissipate the stresses / tensions and compressive forces so the structure does not fail.  To get that in cast iron, just make the casting thick enough!

So back to my original question – when did ‘it’ go ‘wrong’?  From the OWWM site, the dates of the real transitions appear to be after WW1, but before WW2.  There were massive technological changes happening around that time, a depression, and so a possible emphasis towards lower cost production.  I’m not an historian, so wiser heads would be able to give a much more considered view, but that is what I am seeing as potential influences on machine manufacture.

I’ll stick with my cast iron machines as much as I can – sometimes the traditional is more than a romantic concept.  Sometimes it also makes good engineering sense!

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