I researched what kind of battery it was: CR2016, some kind of Lithium battery.
And boy, what a brain fart: I meant half a year, so six months. It's been a few years since I used that watch regularly, but I was impressed with the endurance of that little battery.
Skagen had these kinds of watches with their Hagen line. Ran on a standard battery for nearly half a month. You could set up notification groups so that the watch would buzz and the watch's hands point to a specific hour.
In my experience, that concern is way outdated.
How to calculate spine values
I want to build myself a spine tester to calculate the spine value of arrow shafts using the ASTM F2031 standard. I do know that I need a 880 gram weight and that I have to measure the amount of flex that the shaft produces when I hang said weight at the center of a 28 inch span off the shaft.
Well, but what then? I can measure the amount of deflection I have then but let's say the shaft is deflected by 1/12th of an inch or some millimetres. How do I calculate a spine value that ranges between 20 to 80 from that?
Can anybody give me a hint or solution?
Too bad there wasn't some sort of conclusion