[hpv-boats] Flex Shaft Material Selection

[Dom Rumbolo]

Hi Rick and the rest of the list,



First of all I’d like to thank you for your huge contribution to human
powered boating.  I’ve followed your threads around the Internet and it’s
been a great inspiration.



I’m starting on my pedal-powered build, using a fiberglass surf ski as the
foundation.  I picked up a T-gearbox at 2:1, and plan to start with the APC
16x16 prop, a 5/16” steel flex shaft, and chain gearing.  As has been
mentioned, finding spring steel in the US is not easy.  Doing some research
on the Internet, this is what I’ve come up with and I’d appreciate your
input:



A search for spring steel yields several grades of steel, including 1095:
http://www.tmtco.com/products/spring-steel.html



Trying to find 1095 steel, I see that it is equivalent to W1 drill rod:
http://forums.dfoggknives.com/index.php?showtopic=6783



Can’t find W1 drill rod in anything longer than 3’, but I see that A2 drill
rod is similar: http://www.onlinemetals.com/toolsteelguide.cfm



A2 drill rod is available in 6’ length and fairly cheap:
http://www.mcmaster.com/#8888k416/ $26 shipped



Alternatively, flexible sewer rod is available:
http://www.flexmax.com/maxlife/cat1.html (MDA-72LC, powder coated) $41
shipped



I’m not sure of the material properties of the sewer rod, but it is nice
that it comes powder coated.  Here is some data on A2 drill rod:
http://cartech.ides.com/datasheet.aspx?i=103&e=262&c=techart



Thanks,

Dominic