Archive for September 28th, 2012

Garden Hose Ball Valve Handle Replacement

The handle cracked and fell off this ball valve while I collected the hoses and suchlike from the Vassar Farms plot:

Ball valve with broken handle

Ball valve with broken handle

Surprisingly, it’s not plastic, but (most likely) some cheap & grainy pot metal that wasn’t designed for durability. Rather than throw out that nice brass and stainless steel valve body, I figured a new handle was in order.

To the Basement Laboratory Machine Shop Wing!

The ball rotates freely inside the valve with the handle missing, so I found an aluminum rod (which, IIRC, was the original kickstand from my Linear Mach III ‘bent) that exactly fit the ball opening’s ID:

Ball valve - removing nut

Ball valve – removing nut

What with it being a dark and stormy night outside (and having shut down all the computers in anticipation of a monster thunderstorm), I decided to get medieval with some hand tools. The first step involved finding an aluminum plate of about the right size and thickness, with markings left over from whatever I’d been building when it last saw the ceiling lights:

Ball valve handle - initial layout

Ball valve handle – initial layout

After carefully drilling & filing the shaft hole, it looked like it’d work fine. Then I realized that, for whatever reason, the original design aligned the handle parallel to the hose when the valve was closed, which made very little sense when analyzed according to the Principle of Least Surprise.

So I drilled-and-filed another hole on the other end at right angles to the first one:

Ball valve handle - proper alignment

Ball valve handle – proper alignment

The original handle had two bumps molded on the bottom that acted as stops at each end of its 90° rotation. I figured a pair of 10-32 screws would suffice, not to mention they’d provide a bit of adjustment in case I blundered the hole positions. I planned to chop these stubs to whatever set the proper length below the plate:

Ball valve handle - trial fit

Ball valve handle – trial fit

It turned out that the proper length was just about exactly that of a 1/4 inch 10-32 set screw flush with the top of the plate, so that’s what I used instead. They’re located one radius out from the outline of the valve body; trace the body shape on the handle in each orientation, eyeball one setscrew radius out from those intersections, and drill the holes.

Lay out a nice handle shape by eye, rough it on the bandsaw, introduce it to Mr Belt Sander for final shaping, touch up the concave corners with a rat-tail file, scuff the flat surfaces clean with a Dremel stainless steel wire brush to produce a used-car finish (nice polish over deep scratches), and it’s all good:

Ball valve handle - top view

Ball valve handle – top view

The knob on the end is actually a foot intended for the bottom of a widget case:

Ball valve handle - bottom view

Ball valve handle – bottom view

It won’t get leak-tested until next year, but what could possibly go wrong?

One thing, perhaps: that screw likely lies too close to the hose, particularly one sporting a replacement connector. I may be forced to bend the narrow part of the handle up a bit…

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