Whitepeak Observatory, Tacoma, WA

~Chair construction details~






~Tray assembly details~




Additional construction Notes:

Measurements given are as accurate as I could get but must be considered approximate. It's best to cut parts as you progress through assembly as some dimentions, such as the exact locations of the 1/2" bolt holes in the chair rail are VERY dependant upon other measurements and dimensions and may vary from chair to chair! The angle of the seat, level, tilted up or tilted down, depends on accurate siting of the bolt holes and bolts. Pre- fitting and marking for accurate drilling of these two holes is a *real* good idea... oak is expensive!!

When you cut the angle from the top of the rear legs be sure and save the wedge scrap and use it to provide a flat surface for the lagscrews. Just glue in place and drill thru.

The 1X1 strut brace that extends between the main rail the chair rides on and the back legs is attached to the rear leg spreader rail with a single 3"long by 1/4dia. carriage bolt and secured with a wingnut.

The seat is 3/4" plywood and the piece that is underneath the front edge is a scrap from the legs. It just gives more thickness for the screws which hold the strap's adjustable buckle. The seat is secured to the chair rails with 1-1/2" long flathead wood screws countersunk into the seat so as not to snag clothing.

The trays will hold a couple three pounds without disortion or undue sag.I find this more than adequitte. But If one wanted to support a laptop, additional braces would be desireable, running from the square tube under the trays to the round rod upright and pinned in place.

The whole tray assembly lays in the space between the chair seat and the2X6 and is attached to the oak chair rails with a special stud that has wood screw threads on one half and machine screw threads on the other half. Ace Hardware has these. the 1X1 alum box is drilled to fit and secured with two wingnuts.

Some dimentions, like the length of the long tray support rail, can be changed according to your personal preferences, wider or narrower. If i did this chair again i would make the rear legs with a wider footprint for a little additional stability. 16" is a little narrow..i'd go for 20".

This design is just an amalgamation of several existant designs. I'm certain it can be improved upon. Please do!

The tray rails are pop-riveted in place.

comments and questions to: mclark (at) cityastronomy.com Back to main page