Introduction: Light Bar With Axial Adjustability

About: Registered Nurse by day

I made a light bar for my new 160 sq ft. art studio. It is a DJ truss with vanity light strips, the novel project was to construct a clamp to connect the pieces. It is easy to grasp:

1. cut a measure of 4x4

2. bore a hole through the middle of the 4x4

3. rip the bored 4x4 lengthwise

4. attach the result to a tubular structure.

Clamp Limitations

1. The axial resistance is not easily adjustable after installation

2. The nature of the materials requires careful management e.g. to avoid splitting the wood, to set resistance of the clamps.

Clamp Benefits

1. Minimal articulation.

The flood light bulbs are relatively heavy, and eight per vanity strip requires weight management. Part of the reason for opting against additional hardware is to keep the load as tight to the frame as possible. It would be possible to modify the setup for more adjustability (with extra hinging), but at the sacrifice of applying additional pressure to the 4x4 clamps.

A more bulletproof setup could be achieved with 6x6's. That scale of design is for another project.

2. Balance/symmetry.

The clamp and load counterbalance. This encourages multiple work spaces. Even for a single work space, the lights in the opposite direction provide indirect ambiance.

System Benefits:

1. Simplicity.

2. Minimal cost.

The greatest upfront costs were the key structures: truss, lights, sockets. The cost of all the wood was about $20 and achieves a very good result compared to a metallic hinging system. The vanity fixtures were chosen as a pre-fab of something that would have required a significant time investment to manually replicate for a negligible mechanical advantage. I would have liked the E26 sockets to be better adhered to their sheet metal backing, but the imperfect socket adhesion is ultimately negligible. While the truss frame is expensive, any comparable frame setup would be just as or more expensive. The LED light bulbs were a bona fide steal. All the bulbs were purchased from Aubuchon Hardware stores in Vermont for $5 each due to a subsidized sale ending December 31st 2014.

One note on the absent drill press: the drilling of the 4x4s does not need to be perfect. A drill press would have been appropriate to use, however.


$120 - (4) 8-socket vanity light fixtures

$160 - (32) LED flood lamps

$130 - 10' DJ truss

$20 - Wood

One untreated pine board ~ 8' long x 9" wide x 3/4" deep

One untreated 4x4, 8' (only 26.25" used in final product)

$20 - Extension cord for shop

$30 -Electrical cabling and multi-tap to wire the rig

$30 - Hacksaw to remove material from the truss

$5 - 1 1/2" spade drill bit

$10 - Long 1/8" drill bit

$5 - Electrical terminals to connect cabling to switches


$530 directly plus tax, time, gas, incidentals

Other materials used:

Work table

Cordless hand drill

Corded hand drill especially for boring the 1 1/2" holes

Assorted drill bits

Assorted wood screws and sheet metal screws

Modified skilsaw for use as a table saw or skilsaw

Misc. lumber to use with skilsaw table saw for guiding/pushing

Woodworking clamps

Sander to smooth any cut material

Shop vacuum

Rulers/tape measures

Speed square

2B and 4B pencils work best to mark wood

Grinding wheel for skilsaw to shorten long 1/8" drill bit from retail length

Gloves, goggles, ear protection, particulate face mask

Bother P-Touch

Electrical switches

Glue gun to adhere switches to clamp segments

Staple gun for wiring

Vise grips to crimp terminals (why does every retail crimper have a Prop 65 warning?)

Cable ties for wiring

Wire nuts for wiring

Pliers for cutting wire

Duct Tape for covering electrical or rough points of cable ties


Preparing the truss

Assemble the truss before doing anything. The truss is made up of two pieces, joined at the middle, raised by two tripods. Label the corners of each of the two truss pieces.

The model of this truss permits the removal, by hacksaw, of 6.0cm+ from the medial aspect, and 1.0+cm of slack from the lateral aspect of each tubular piece. This was performed to expand the tripod bases more fully with room size limits.

The T-braces (the hardware which attaches the tubular frame in perpendicular fashion) only need partial disassembly for the truss to be removed for modification. By having the T-braces in place from the initial assembly, installation of the modified truss is relatively easy.

Preparing the vanity light fixtures

From the retail package, each vanity fixture has a chrome valance and stabilizers. Extract the single useful piece, the sheet metal attached to eight E26 ceramic sockets, and remove the grounding tie-down.

Note: due to the single mount point of each ceramic socket, the fixtures mechanically support fewer than 180 degrees of rotation. This means an unobstructed 180+ degree rotation may angle the load self-destructively.

Preparing the support boards

The sheet metal of the vanity fixture measures approximately 43 3/4" long x 4" wide. Take a pine board of approximate actual dimensions 8' long x 9" wide x 3/4" deep and quarter it to produce four boards measuring ~ 4' long x 4.5" wide x 3/4" deep. Use one board to stabilize each vanity; it also provides a means for manual angle adjustment.

Step 2: MAKE CLAMPS Part 1

Cut 4x4 pieces to length

Measure the triangular truss support elements to decide how long of a 4x4 clamp is permissible; 6" is sufficient. Measure and cut multiple segments; I cut eight.

Mark each end of each segment from corner to corner, making an "X" to center drilling. Use a 2B or 4B pencil from an art store: the graphite is softer and releases more easily.

Drill through the center of each 4x4 piece

You can use a 1 1/2" spade drill bit with a corded hand drill. With this method, drill from one side all the way through the other. Reasonable accuracy produces fine results. With a hand drill, cut extra stock to account for errors.

A drill press with a hole saw would be ideal, but the tolerance of the intended system doesn't require that degree of accuracy.

Do note: drilling from each end to the middle yields poor results.

Technical inaccuracies are evident by hand drilling all the way through from one end through the other, but:

1.) only one face side of each 4x4 clamp half is used, and

2.) the materials are forgiving.

Therefore, there is no mechanical disadvantage to hand drilling, and the technical imperfections are negligible (and may contribute to axial resistance... [a good thing...]).

Mark each set of clamps with a permanent marker to identify them for fitting.

Rip each bored 4x4 section in half

With a table saw, produce two marrying clamps.

Step 3: MAKE CLAMPS Part 2

Drill through the two halves to prepare for clamping
The procedure for this step is simpler with a drill press.

Using a hand drill, take the following sub-steps to ensure the clamp screws are seated in the center of each clamp base in straight holes.

Using a long 1/8" bit compensates for the inaccuracy of hand drilling. If you get a 12" long 1/8" bit from a store, just cut and grind it down to about 5-6" to reduce error.

1. Measure out drill points for each base of one clamp.

No need to measure the second clamp.

2. Drill from the center side of the clamp to the outer side.

3. Adhere both 4x4 clamp halves with woodworking clamps and use the long 1/8" drill bit to follow the drill hole just made to complete the straight line through both 4x4 clamp halves.

4. Finally, with a larger (1/2") drill bit, bevel the edges of each 1/8" drill hole so each 3" drywall screw will sit flush and recessed to permit mounting the vanity and its support board.


Adhere the 4x4 clamps to the truss:

1. Place the first half of each clamp set on the work surface. Place the truss in the desired fit location.

2. Place the second half of a clamp in place.

3. Before securing the first screw, level the clamp halves with 4-5 stacked washers at the proposed side. Prefer a tighter gap, as opposed to a wider one, when approximating a level.

4. Insert the first screw fairly tight.

5. Remove the washers.

NOTE: keeping the washers in beyond this point will reduce/eliminate axial tension. On the other hand, not using anything to level the clamps will result in a poorly aligned and/or broken clamp. By using props (the washers) for a single screw, the clamps will stay mostly level during the insertion of the other screws and will bend just enough to provide appropriate axial tension.

6. Insert the remaining screws lightly, then tighten appropriately, feeling for tension.

If there is too much tension, loosen some screws.

If there is not enough tension, either add more screws in the intermediary material or remove all the screws and start over.


Mount the support boards

Each vanity should be mounted to a wood board for stability.

Center and mount the support board on the faces of two clamps. Use 1 1/4" drywall screws. Beveling isn't needed for soft wood. You can drill close to the middle of the clamps due to the thickness of the materials.

Insert the screw so it is flush with the material because the vanity bar will mount on top.

Mount the vanity bars

Center and mount the vanity bars. Use 2-4 sheet metal screws per light socket.

Wire it
Cut household extension cords to obtain wiring with socket prongs. Use wire nuts to attach the wires. You can staple gun some slack to the 4x4 clamps; cable tie the rest to the truss frame.

Add switches to the system by mounting them to short segments of a 4x4 clamp. Plug the standard prongs into a multi-tap upon final installation.

Step 6: WRAP IT UP

Attach the truss pieces
Note in the pictures how the truss bolt assembly has a series of added washers. By sawing 6.0cm off the medial aspect of each of the four steel tubes, the structure assembles with the fly nut inside the truss support beams, rendering the stock bolt too long. Use more washers for the cheap and easy fix. Interestingly, the stock holes of the tubular frame perfectly accommodate the length modification.

Mount the assembled truss to the tripods

Use an extension cord to help the multi-tap reach the wall outlet.

Cable tie any slack.

Install the flood lamps and fire it up

Step 7: Final Thoughts

1. The clamping mechanism could be used with a tripod or torchiere floor lamp.

Before this project I modified several torchieres which achieved bright light but only from a single vertical source, like stadium lighting, which produces many shadows. One major drawback was the stability of the stand, which could be improved upon with a tripod base.

Different circumferences of things to clamp onto could be accommodated by a variable width borer.

Recall that Circumference = (pi) Diameter

2. A $530 light rig is a little expensive, but breaking it down, it's about $16.56 per affixed bulb to a frame which is sturdy and portable. While you're visiting Vermont for the slopes, come check out the light bulb sales!

3. My build can adjust about 84 degrees, 42 each direction from horizontal.

Downward/upward lighting might be achieved by sizing the counterbalance to fit through the truss supports. Or, some support beams could be removed while maintaining structural integrity.

4. This is a great tool for light therapy. Objects and colors in the room show very clearly with this setup, as opposed to residential and commercial settings which have sparse/dim/poor lighting. I'm not sure about UV output or vitamin production, but some part of the brain says the sun is out when things look bright.

I am very pleased with the build and hope you liked it!

Make it Glow!

Participated in the
Make it Glow!

Wood Contest

Participated in the
Wood Contest