Making a Round
Tabletop Light Source
- Table saw,
to cut long length Burke tube into 9" lengths
- Band saw to
cut wood disks
- Small, circular
hand-held saw, 3-3/8 (Makita 5090 D or comparable) to cut four
windows in the tube
- Drill, with
bit (for cord hole), 1/8" bit (for pilot holes) and 1" bit (for
vent holes in disk). (Drill press makes preparation of disk much
- Phillips head and regular in small and medium sizes
- Wire cutter/stripper
Supplies for one Round Light Source
- 1 sheet sandpaper
- 1 Tube - Burke
or Sono Tube, used for concrete construction, 10" diameter -
preferably unwaxed, cut to 9" lengths. Sometimes sold only in
10-ft. lengths. Approximately $2/ft.
- 1 sheet of
Plywood (12" x 12" x 3/4") for circular disk. Try to get scraps.
- 1 Electrical
cord - 8-ft., heavy-duty cord with switch and plug attached
- 4 #6 pan head
sheetmetal screws (3/4") (disk to tube)
- 2 #6 pan head
sheetmetal screw (1/2") (porcelain, disk bracket)
- 1 6/32 bolt
and hex nut (1/2")(wall bracket)
- 1 Standard
porcelain lamp fixture
- 1 Plastic
cord fastener ("p-straps")
Round Light Source
- If you are
making more than one Round Light Source, tubes can be cut into
9" lengths using a table saw with a 9" jig.
- Use a small
(5/8") circular, hand-held saw to cut four windows (4" x 2" 1/4")
in the tube.
- Cut disk from
plywood on a band-saw to fit inside of tube, snug, but not too
tight. Drill five 1" vent holes in disk.
- Drill four
holes (A) in tube and disk together, at the end of the tube that
is opposite from the "windows." Holes should be approximately equally
spaced around the circumference of the tube.
- Drill one
hole (B) for cord in the side of the tube.
- Drill one
hole (C) for P-strap to support cord inside of tube.
- Drill eight
holes (D) for brass fasteners to hold masks.
- Sand disk
- Attach the
tube to the disk with the 3/4" #6 panhead sheetmetal screws.
- Push cord
through (B) large 7/16" pre-drilled hole in tube. This must be
done BEFORE attaching porcelain fixture.
- Attach brackets
to the wall of the tube (with the 1/2" 6/32 bolt and hexnut)
and to the disk (with the 1/2" #6 panhead sheetmetal screw).
- Unscrew top
of porcelain fixture. Trace outline of fixture, including holes
for screws on center of disk, and drill two pilot holes for screws
- Attach porcelain
fixture to the center of the disk, using 1/2" #6 panhead sheetmetal
- Attach black
and white wires to porcelain fixture. Third wire is not necessary
and can be cut since no part of the Round Light Source is metal,
so it does not have to be grounded. Prepare the wires by twisting
them so that they are tightly bound. Attach the black wire to
the brass screw and the white wire to the gray screw. Bend them
in a U-shape, and attach to the screws as illustrated: