The Azimuth Box

The Azimuth Box

The azimuth box performs two functions. First it raises the scope to a comfortable viewing height and second is allows you to rotate the scope in azimuth. By using a small portable table I was able to make the azimuth box much shorter. However, the only way to make the azimuth box fit into the suitcase was to disassemble it. That way you have four flat pieces of wood that will stack on top of each other inside the case. That worked fine, but I did not like the idea of trying to re-assemble the box in the field in the dark. Also, repeated assembly and disassembly cycles using wood screws would soon enlarge the screw holes and make the whole assembly loose and wobbly.

Two innovations solved these design problems. The first was to use a dado blade to cut shallow notches in the top of the azimuth setting circle. The four sides of the azimuth box fit into these notches and, since the notches are cut square, the sides of the azimuth box are automatically aligned. Great for assembly in the dark. The second innovation was to use T-nuts. T-nuts are devices which allow you to insert metal machine threads into a piece of wood. The T-nuts are installed into a small strip of pine molding which is then glued and nailed to the edge of the azimuth box side. By putting these strips of molding on the appropriate edges of the azimuth box you can use metal machine screws to hold the edges together and hold the box to the top of the azimuth setting circle. If you are careful in installing these nuts and in cutting the notches, the screw holes and the T-nuts will align perfectly when you place the four sides of the azimuth box in the notches you cut into the top of the azimuth setting circle. This makes field assemble much easier.

This photo shows how to cut the notches into the top of the Azimuth Setting circle. While the work piece is still square, you cut four shallow notches (about 1/8" deep).

A dado blade makes this easy since it will cut the notches the exact width you need. However, you can cut them by making multiple passes with a standard saw blade.

The sides of the azimuth box will fit inside these notches and hold the base square after it is assembled.

This photo shows one T-nut installed in the center of a small pine strip.

The white material is wood glue for attaching the strip to the edge of the azimuth box side. I also used a small air-nailer to attach the pine strip to the edge of the box side.

I attached a pine the strip to both vertical and one horizontal edge of the azimuth box side. I used a total of six pine strips and eight T-nuts.

This photo shows how the azimuth box fits together.

You can see three of the four sides of the azimuth box. Two of the sides are the same size while the other two consist of a short and long side.

You can also see two pine strips attached to the short side along the left and right edges and one pine strip along the bottom of the right side of the box.

The four sides of the azimuth box are seated in the notches of the azimuth scale (which is still square at this time) and the entire assembly is being held together by the one clamp. This shows that the notch design is very stable even without any screws installed into the T-nuts.

This is the completed azimuth box setting on the azimuth base.

The azimuth scale is now circular, cutouts have been made in all sides to make the assembly lighter and the circles have been cut for the elevation bearings.

You can also see that small brass screws are now holding the assembly together instead of a clamp and you can see the elevation scale.

Complete Azimuth Box

This shot is looking straight down into the inside of the azimuth box.

You can see the short pipe that serves as the azimuth rotational axis and four holes I drilled into the azimuth scale to lighten the assembly.

You can also see the four white teflon chair tips that serve as the contact points for the elevation bearings.

This is the bottom of the azimuth box showing the bottom of the azimuth setting circle.

I used six teflon chair tips to serve as glides for the rotation about the azimuth axis.

These chair tips move smoothly on top of the azimuth base counter top material.

You generate the scales using a program by Glenn Ashmore from Macon called Nth Degree. Go to the Setting Circles page to download it.

Bottom View

Go to the Azimuth Base Page

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