Bandsaw Worklight

Having hacked back the end of the USB gooseneck extension, a tweak of the COB LED heatsink mount for my desk lamp produces a smaller version for a 1.8 W LED:

Chip On Board Heatsink Mount - Bandsaw Lamp - solid model
Chip On Board Heatsink Mount – Bandsaw Lamp – solid model

That fits half of a random heatsink, bandsawed just to the far side of the middle fin and milled flat.

Ream out the 5 mm hole with a #8 drill for a snug fit around the gooseneck, jam gooseneck in place, dab epoxy on the corners of the recess, mash the heatsink in place, solder wires to LED, smear epoxy on the aluminum backplate, clamp while curing:

USB Gooseneck - LED assembly
USB Gooseneck – LED assembly

And it looks pretty good, if I do say so myself:

USB Gooseneck - on bandsaw
USB Gooseneck – on bandsaw

The hook-n-loop tape holding the cable to the bandsaw gotta go, but should suffice until I conjure a better mount.

The alert reader may wonder how a 9 V COB LED runs from a 5 V USB cable with nary a trace of a voltage booster to be seen. Well, that’s not really a USB cable any more; I paralleled the red+white and black+green wires for lower resistance, then hacked a 9 VDC power supply into an old USB hub:

Hacked USB hub - PCB mods
Hacked USB hub – PCB mods

I ripped out the upstream USB plug, hotwired the 9 V supply where the 5 V USB wires used to be, soldered jumpers on the downstream sockets to short the outer two pin pairs together, razor-knifed the power leads going into the epoxy-blobbed USB controller, and declared victory:

Hacked USB hub - in use
Hacked USB hub – in use

Admittedly, that “In Use” LED runs a bit brighter now.

I have a few other tools on that bench in need of LED lights; when I build ’em, they can all plug into this hub. No reason to invent new connectors & cables & all that. It may need a power switch.

Turns your stomach, eh?

The OpenSCAD source code as a GitHub Gist:

// Chip-on-board LED light heatsink mount for desk lamp
// Ed Nisley KE4ZNU December 2015
// February 2017 - rectangular COB, smaller heatsink
Layout = "Show"; // Show Build
//- Extrusion parameters must match reality!
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleWindage = 0.2;
Protrusion = 0.1; // make holes end cleanly
inch = 25.4;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
// Dimensions
ID = 0; // for round things
OD = 1;
Gooseneck = [3.0,5.0,15.0]; // anchor for end of gooseneck
COB = [30.0,11.0,2.5]; // Chip-on-board LED module
Heatsink = [37.1,19.2,10.0]; // overall
HeatsinkBase = 2.0; // solid base below fins
HSLip = 1.0; // width of lip under heatsink
BaseMargin = 2*2*ThreadWidth;
BaseRadius = 3*ThreadThick + Gooseneck[OD]/2; // defines slab thickness
BaseSides = 2*4;
Base = [(Gooseneck[LENGTH] + Gooseneck[OD] + Heatsink[0] + 2*BaseRadius + BaseMargin),
(Heatsink[1] + 2*BaseRadius + 2*BaseMargin),
echo(str("Slab thickness: ",Base[2]));
// Useful routines
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(r=(FixDia + HoleWindage)/2,
//-- Lamp heatsink mount
module Lamp() {
difference() {
translate([(Base[0]/2 - BaseRadius - Gooseneck[LENGTH]),0,0])
for (i=[-1,1], j=[-1,1])
translate([i*(Base[0]/2 - BaseRadius),j*(Base[1]/2 - BaseRadius),Base[2]/2])
translate([(Heatsink[0]/2 + Gooseneck[OD]), // main heatsink recess
(Base[2] + Heatsink[2]/2 - HeatsinkBase)])
cube((Heatsink + [HoleWindage,HoleWindage,0.0]),center=true);
translate([(Heatsink[0]/2 + Gooseneck[OD]),0,HeatsinkBase]) // lower lip to shade lamp module
cube(Heatsink - [2*HSLip,2*HSLip,0],center=true);
translate([0,0,Base[2]/2]) // goooseneck insertion
rotate([0,-90,0]) rotate(180/8)
translate([0,0,Base[2]/2 + Gooseneck[ID]/2]) // wire exit
translate([Gooseneck[OD],0,(Base[2] - HeatsinkBase - Protrusion)/2]) // wire slot
cube([2*Gooseneck[OD],Gooseneck[ID],(Base[2] - HeatsinkBase + Protrusion)],center=true);
// Build it
if (Layout == "Show") {
if (Layout == "Build") {


4 thoughts on “Bandsaw Worklight

    1. This is sorta-kinda an upstream version of the USB killer dongle (loose on the Internets for a year or two) that applied a boost converter across the data lines…

    2. 9V on a USB connector… you really do live dangerously, don’t you :)

      I spent the weekend pumping 35V from a rewound microwave oven transformer into 24V 250W silicone heater to allow for a proper aluminum build plate in what passes for a 3D printer around here. I see adding a thermal switch AND a thermal fuse to that kludge before I let it out of my sight for more then a minute. Fun times :)

Comments are closed.