Tour Easy Daytime Running Light: Improved Ball Mount

The original ball around the flashlight consisted of two identical parts joined with 2 mm screws and brass inserts:

Flashlight Ball Mount - flattening fins
Flashlight Ball Mount – flattening fins

Providing enough space for the inserts made the ball bigger than it really ought be, so I designed a one-piece ball with “expansion joints” between the fingers:

Fairing Flashlight Mount - Finger Ball - solid model
Fairing Flashlight Mount – Finger Ball – solid model

Having Slic3r put a 3 mm brim around the bottom almost worked. Adding a little support flange, then building with a brim, kept each segment upright and the whole affair firmly anchored.

Fairing Flashlight Mount - Finger Ball - solid model - support fins
Fairing Flashlight Mount – Finger Ball – solid model – support fins

Those had to be part of the model, because I also wanted to anchor the perimeter threads to prevent upward warping. Worked great and cleanup was surprisingly easy: apply the flush cutter, introduce the ball to Mr Belt Sander, then rotate the ball around the flashlight wrapped with fine sandpaper to wear off the nubs.

The joints between the fingers provide enough flexibility to expand slightly around the flashlight body:

Flashlight Mount - finger ball
Flashlight Mount – finger ball

I made that one the same size as the original screw + insert balls to fit the original clamp, where it worked fine. The clamp ring applies enough pressure to the ball to secure the flashlight and prevent the ball from rotating unless you (well, I) apply more-than-incidental force.

Then I shrank the ball to the flashlight diameter + 10 mm (= 5 mm thick at the equator) and reduced the size of the clamp ring accordingly, which made the whole mount much more compact:

Flashlight Mount - LC40 - finger ball - side
Flashlight Mount – LC40 – finger ball – side

Here’s what the larger mount looks like in action:

The flashlights allegedly puts out 400 lumen in a fairly tight beam. The fairings produce a much larger and brighter glint in full sunlight than the flashlights, so I think they’re about the right brightness.

The OpenSCAD source code for the new ball as a GitHub Gist:

//- Slotted ball around flashlight
// Print with brim to ensure adhesion!
module SlotBall() {
NumSlots = 8*2; // must be even, half cut from each end
SlotWidth = 2*ThreadWidth;
SlotBaseThick = 10*ThreadThick; // enough to hold finger ends together
RibLength = (BallOD - LightBodies[FlashIndex][F_GRIPOD])/2;
difference() {
intersection() {
sphere(d=BallOD,$fn=2*BallSides); // basic ball
cube([2*BallOD,2*BallOD,BallLength],center=true); // trim to length
PolyCyl(LightBodies[FlashIndex][F_GRIPOD],2*BallOD,BallSides); // remove flashlight body
for (i=[0:NumSlots/2 - 1]) { // cut slots
SlotCutterLength = LightBodies[FlashIndex][F_GRIPOD];
rotate(a + 360/NumSlots)
if (Support) {
for (i=[0:NumSlots-1]) {
a = i*360/NumSlots;
rotate(a + 180/NumSlots)
translate([(LightBodies[FlashIndex][F_GRIPOD] + RibLength)/2 + ThreadWidth,0,BallLength/(2*4)])

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