Propane Tank QD Adapter Tool

Although it’s common practice to exchange your empty 20 pound propane tank for a full one, I vastly prefer to keep my own tanks: I know where they’ve been, how they’ve been used, and can be reasonably sure they don’t have hidden damage. Two of my tanks have old-style threaded connections, but the barby has a quick-disconnect fitting on the regulator and I’ve been using an adapter on those tanks.

The adapter comes with a plastic tool that you use to install it in the tank valve. In principle, you insert the tool into the adapter, thread the adapter into the valve, then tighten with a wrench until the neck of the plastic tool snaps, at which point you eject the stub and the adapter becomes permanently installed. I don’t like permanent, so I carefully tightened the adapter to the point where the O-ring seals properly and the tool didn’t quite break. I’ve always wanted a backup tool, just in case the original broke, and now I have one:

Propane QD Adapter Tool - in adapter

Propane QD Adapter Tool – in adapter

It fit into both the adapter body and the 5/8 inch wrench (the OEM tool is 9/16 inch) without any fuss at all:

Propane QD Adapters - OEM and printed

Propane QD Adapters – OEM and printed

The solid model has a few improvements over the as-printed tool above:

  • Shorter wrench flats
  • More durable protrusions to engage the locking balls
Propane QD Adapter Tool

Propane QD Adapter Tool

It took about an hour to design and another 45 minutes to print, so it’s obviously not cost-effective. I’ll likely never print another, but maybe you will.

The OpenSCAD source code:

// Propane tank QD connector adapter tool
// Ed Nisley KE4ZNU November 2012

include </mnt/bulkdata/Project Files/Thing-O-Matic/MCAD/units.scad>
include </mnt/bulkdata/Project Files/Thing-O-Matic/Useful Sizes.scad>

//- Extrusion parameters must match reality!
//  Print with +1 shells and 3 solid layers

ThreadThick = 0.25;
ThreadWidth = 2.0 * ThreadThick;

HoleWindage = 0.2;

function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

Protrusion = 0.1;			// make holes end cleanly

//----------------------
// Dimensions

WrenchSize = (5/8) * inch;		// across the flats
WrenchThick = 10;

NoseDia = 8.6;
NoseLength = 9.0;

LockDia = 12.5;
LockRingLength = 1.0;
LockTaperLength = 1.5;

TriDia = 15.1;
TriWide = 12.2;										// from OD across center to triangle side
TriOffset = TriWide - TriDia/2;		// from center to triangle side
TriLength = 9.8;

NeckDia = TriDia;
NeckLength = 4.0;

//----------------------
// 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,
h=Height,
	   $fn=Sides);
}

module ShowPegGrid(Space = 10.0,Size = 1.0) {

Range = floor(50 / Space);

	for (x=[-Range:Range])
	  for (y=[-Range:Range])
		translate([x*Space,y*Space,Size/2])
		  %cube(Size,center=true);

}

//-------------------
// Build it...

$fn = 4*6;

ShowPegGrid();

union() {

	translate([0,0,(WrenchThick + NeckLength + TriLength - LockTaperLength - LockRingLength + Protrusion)])
		cylinder(r1=NoseDia/2,r2=LockDia/2,h=LockTaperLength);

		translate([0,0,(WrenchThick + NeckLength + TriLength - LockRingLength)])
		cylinder(r=LockDia/2,h=LockRingLength);

	difference() {
		union() {

			translate([0,0,WrenchThick/2])
				cube([WrenchSize,WrenchSize,WrenchThick],center=true);

			cylinder(r=TriDia/2,h=(WrenchThick + NeckLength +TriLength));

			cylinder(r=NoseDia/2,h=(WrenchThick + NeckLength + TriLength + NoseLength));
		}

		for (a=[-1:1]) {
			rotate(a*120)
				translate([(TriOffset + WrenchSize/2),0,(WrenchThick + NeckLength + TriLength/2 + Protrusion/2)])
					cube([WrenchSize,WrenchSize,(TriLength + Protrusion)],center=true);
		}
	}
}
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  1. #1 by Neil Wagner on 10-February-2013 - 14:26

    I couldn’t find a plastic adapter anywhere. What I did was take a bolt with a 1/2 drive (6 point) ground down every other point.

    Fits and works great.

    • #2 by Ed on 10-February-2013 - 19:50

      Fits and works great.

      And, being steel, will last basically forever: I like it!

      With that said, being able to print out a thing that’s just the right shape can be really addictive…