The tied bolts on a propeller (updated)

I came across this photo from Kelly Trimble in my Light From A Low Sun contest (you'll have seen it if you saw the finalists' gallery). And apart from the beauty of the machine and the photo, I now noticed the strings in the bolts. And I noticed how they go across in a way so if one bolt should loosen, it'll only tighten another bolt, so they keep each other tight. Ingenious!

I mentioned it to our resident Engineer Extraordinaire, Bert, and he told me that not only are the bolts still done like this today, but it is a crime to tamper with the strings if one is not a certified airplane mechanic!

(Click for big pic.)

Kelly wrote to me:
A few weeks ago, a friend completed a homebuilt aircraft.  Before the maiden flight, I took several photos.  He had to wait until late in the day for the winds to die down, so I got several with the sun just over the horizon.  I call this photo 'Before the Maiden Flight". 
[...] The subject of that contest photo, however, was the prop spinner hub.  The builder owns a machine shop, and is famous for going 'over the top' when fabricating otherwise unexciting parts for his own use.  That propeller spinner hub was not cast--it was machined from a solid aluminum billet, letters and all.  If a customer had contracted for that part, it would have probably been a two thousand dollar machining job. 

I have included some photos of the plane with Wayne Edson of Hollister, Missouri, the builder.  You asked how much of the plane he built himself.  Actually it was Wayne together with his father, and they built almost all of it.  The design originated in the 1920s with somebody named Pietenpole, and there have been hundreds of this design, which is now fairly standard, built over the years all over the world.  Most people who make homebuilt aircraft will usually buy a kit with most of the parts already fabricated which they then assemble.  Since nobody owns the design for Pietenpoles, nobody makes a kit, but most of the components are commercially available.  However, Wayne owns a fairly large machine shop with around a dozen CNC machines and a foundry pattern shop (essentially a large woodworking shop), so he is well equipped to fabricate a lot of the parts that most people would have bought off of the shelf. 

At one point, they used me for ballast while temporarily attaching the engine:

Note the craftmanship on those canoes!