Parts for Chair Base:
1. For the groundboard cut a 36" by 36" piece of plywood and draw lines from corner to corner to locate center:
2. Drill 3 inch diameter hole with a circular hole saw in the center of the plywood. This hole will be a "hand-hole" for easily carrying the chair base. I drilled this hole just off center for my chair, at 20 inches from the front of the chair base (see dimensions in next step).
3. Drill a hole for the "Seat Base For Boat Pedestal" 20 inches from the front of the chair base and 12 inches from the side:
4. Mount "Seat Base" to plywood by drilling six holes and using six 5 inch 1/4-20 bolts.
5. Cut two -2x4's at 30 inches length. These go between the char legs. Place these alongside the two sets of three bolts that were installed in Step 4, mark positions for drilling holes. Drill three holes in each 2x4 and mount on bolts with washers and nuts:
6. Secure the ends of the 2x4's by using 9x2 wood screws as shown:
7. Locate the position where the drill will be mounted. Place the chair base on ground with reclining chair placed on it. Sit in the chair and with the control drill in your right hand and mark the most comfortable position of the drill while moving through all vertical positions of the reclining chair.
8. Now that the drill position is marked, the bike chain will be resized for this position. Drill out links in the chain as needed and use a chain link kit to reconnect the chain. Drill a 2 inch hole in the plywood at the location of the small sprocket and drill. I made an oval shaped hole so I could make adjustments in the direction of the chain tension.
9. For mounting the drill, cut two 2x4 pieces at 9 inches length and two 2x4 pieces at 3.5 inches length. These will be used to support the drill's handle/battery as shown below. I measured the height of the drive chain above the ground board at the large sprocket and it was 1/2 inch, so the small sprocket on the drill arbor will need to be at this same height above the ground board.
10. Cut off one corner of one of the 9 inch 2x4's as shown and drill 1/4 inch holes through the base and top of the drill mount. Cutting off the corner will allow the outer board to swing away for easy removal of the drill.
11. Install 7 inch 1/4-20 bolts through the top and base of the drill mount and tighten with washers and wing nuts. Attach the drill mount to the correct position on the plywood with 9x2 wood screws. The top bolt can be loosened and the outer board pivoted back for installation and removal of the drill.
12. Using the screws provided, place the two closet door rollers in a position to brace the drill chuck and keep tension on the drive chain:
12. The chair base is now complete! Place it on the ground board as shown below. Check the clearance between the ground board and chair base while rotating the chair base 360 degrees. My "Seat Base For Boat Pedestal" was angled somewhat as purchased ( maybe to provide more forward support when installed in boats?), so I had to shim it with thin strips of wood (wooden ruler) as shown in the second photo below:
13. To keep the chair base from tilting on the ground board, I added four 1.25 inch roller casters to the bottom of the chair base. The four casters were placed to evenly support ones' weight when sitting in the chair. The casters were located at 18 inches radius from the center of the "Seat Base for Boat Pedestal". You can adjust how well the roller casters ride on the ground board by changing the number of large metal washers on the center post of the "Seat Base for Boat Pedestal". I found that two washers worked best with my bino chair.
UPDATE 7/28/06 - Added Step:
Step 14. I found that the top of the drill moved from side to side somewhat when in operation, especially when changing directions. To secure the drill better, I added a metal shelf bracket to the chair base to which the drill is secured using two 3-inch hose clamps. I used rubber grippy material under the hose clamps.
Next Page - Component No. 3 - Binocular Mount
Big Astronomy Binoculars - Large Astronomy Binoculars
Detailed procedure for drill-powered astronomy binocular chair.
Binocular mount for Apogee 25X100 large astronomy binoculars.
Comfortable observing with big astronomy binoculars.
Reclining chair for large astronomy binoculars.