Parts for Chair
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
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
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.
- 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.
Page - Component No. 3 - Binocular Mount
Big Astronomy Binoculars - Large Astronomy
Detailed procedure for drill-powered
astronomy binocular chair.
Binocular mount for Apogee 25X100 large
Comfortable observing with big astronomy
Reclining chair for large astronomy binoculars.