Wednesday, March 30, 2016

DIY Harrow Blade - Sun Dial

Started thinking about the lake again and decided we needed a substantial Sundial. There are soooo many types to choose from that I had to apply my "just make something" rule. It is also just a beginning and next year may bring something different.

The lake is located at 44.66 Lat. and on-line there is a plethora of materials for designing and making them.

I picked a 45deg pattern as a guide and rummaged around the shop for a piece of something and found a harrow blade that I had purchased for another project.

The curvature is a problem because it causes the shadow to curve.

In CAD I developed the curved hour marks. 3 points for each curve.
I laid it out old school; clamping the disc to a piece of plywood so that I had easy X & Z axis.

I got to use my newly restored CSE height gauge.

Then I got to use my Accu-Arc for the 1st time to scribe and then mark the curves.

And lastly I used my chalk board compass with the gold marker to stripe the circles.

Mostly complete.
Drilled 3 holes for 1/4-20 screws.
Don't drill thru Harrow blades, takes a couple of bits per hole and it turns out I didn't need them.

Some other mounting / leveling method would be easy enough.
I didn't want to weld onto the disc and burn off the finish.

The next post will be on Memorial Day when it gets positioned by the lake.

FYI turns out daylight saving time offsets the numbering system!

After the first summer in use I wanted to fix the issue of numbering and the color issue.

I went with a light camo green, black (Sharpie) markings and a clear cote over it
I still got the numbers wrong so I substituted the stickers, maybe next year I will get it right.

Serendipity says; with the hemispherical shape of the blade you can read the time of day from your seated position!!