Instrumentation – The Great Quadrant: Day 8

It’s said that a project involves blood, sweat, and tears. Today was two of the three. Somehow have managed not to get splinters till today, but got a pretty good one. It was also hot in the workshop:

I mean, it wasn’t Lilies hot, but we were moving.

Regardless, we ended up working for six hours today. We started by drilling the holes in the quadrant and the central post for the axle and the rod to help rotate it.

This had to be lined up exceptionally carefully because the center of rotation will need to be aligned perfectly as the plumb will hang down from this and it needs to hand perfectly with the 0º mark on the scale (which will come later).

Our plan was to use $\frac{1}{2}$” steel pipe as the axle, but there wasn’t a drill bit that was quite right, so we ended up having to use a rasp to size the hole appropriately.

Next, we placed a hole in the central column about half way down so we could slide a dowel through to help orient it.

To help manage the spacing of the quadrant from the central pole (as well as making it easier to transport), the axle is actually a few separate pieces of pipe with caps on the ends and a coupler to maintain the spacing. It wasn’t fully assembled here, but here’s the first piece through the column.

Also, there’s been some trouble sliding the legs into the top. As such, we sanded them down so they fit more easily, and added stamps to denote the proper orientation.

Lastly, to make this as durable as possible, we applied a waterproofing stain.

This really helps achieve the same overall color as the source image. Although the quadrant itself will be painted a different color, we still stained and sealed that.

So all that’s left at this point is to finish mounting the quadrant, hang the plumb line, paint the quadrant and its scale.

T minus 26 days.