Category: Machine Shop

Mechanical widgetry

Hydrant Wrench

The Slic3r preview shows a bit more detail:

Hydrant Wrench - Slic3r preview — Hydrant Wrench – Slic3r preview

Even an inch-thick handle wouldn’t have enough mojo for the task.

Wikipedia has the equations you need to go from the easily measured “height” (vertex to opposite side) dimension to the pentagon’s “outside radius”, which equals the radius of the circumscribed circle needed by OpenSCAD.

The OpenSCAD source code as a GitHub Gist:

	// Hydrant Wrench
	// Ed Nisley KE4ZNU – September 2017

	/* [Extrusion] */

	ThreadThick = 0.25; // [0.20, 0.25]
	ThreadWidth = 0.40; // [0.40]

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

	Protrusion = 0.01; // [0.01, 0.1]

	HoleWindage = 0.2;

	//- Sizes
	/* [Dimensions] */

	NumFlats = 5; // this is not a variable for this geometry!

	Height = 39.0; // pentagon flat-to-vertex measurement
	Side = Height / 1.539;
	echo(str("Side:",Side));

	Radius = Side / 1.176;
	echo(str("Radius: ",Radius));

	WrenchDia = 2*Radius; // pentagon circumcircle diameter
	echo(str("Wrench dia:",WrenchDia));

	JawWidth = 10.0;

	JawOD = 2*JawWidth + WrenchDia;
	echo(str("Jaw OD: ",JawOD));

	WrenchThick = 5.0;

	HandleLength = 2*JawOD;
	HandleWidth = 25.0;

	//- Build things

	difference() {
	linear_extrude(height=WrenchThick,convexity=4) {
	hull() { // taper wrench body to handle
	circle(d=JawOD);
	translate([0.75*JawOD,0,0])
	circle(d=HandleWidth);
	}
	hull() { // handle
	translate([0.75*JawOD,0,0])
	circle(d=HandleWidth);
	translate([HandleLength,0,0])
	circle(d=HandleWidth);
	}
	}
	translate([0,0,-Protrusion])
	rotate(180/NumFlats)
	cylinder(d=WrenchDia,h=(WrenchThick + 2*Protrusion),$fn=NumFlats);

	translate([WrenchDia,0,WrenchThick – 3*ThreadThick])
	linear_extrude(3*ThreadThick + Protrusion,convexity=10)
	text(text=str("Fire Hydrant!"),size=8,spacing=1.20,font="Arial",halign="left",valign="center");
	}

view raw Hydrant Wrench.scad hosted with ❤ by GitHub

Sorry ’bout that … had to do it.

2017-10-04

Tour Easy Headset Wrench

The headset on my Tour Easy ‘bent worked its way loose, which led to a disturbing discovery: the headset wrench I made from a discarded flat wrench vanished with the shop tools donated to MakerSmiths.

Fortunately, we live in the future:

Tour Easy Headset Wrench - Slic3r preview — Tour Easy Headset Wrench – Slic3r preview

A thin plastic wrench is absolutely no good for torquing down the locknut, but that’s not what it’s for. Adjust the bearing race to the proper preload with this wrench, hold it in place, then torque the locknut with the BFW.

The OpenSCAD source code as a GitHub Gist:

	// Tour Easy Headset Wrench
	// Ed Nisley KE4ZNU – September 2017

	/* [Extrusion] */

	ThreadThick = 0.25; // [0.20, 0.25]
	ThreadWidth = 0.40; // [0.40]

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

	Protrusion = 0.01; // [0.01, 0.1]

	HoleWindage = 0.2;

	//- Sizes
	/* [Dimensions] */

	WrenchSize = 32.0; // headset race across-the-flats size
	NumFlats = 8;

	JawWidth = 10.0;

	JawOD = 2*JawWidth + WrenchSize;
	echo(str("Jaw OD: ",JawOD));

	StemOD = 23.0;

	WrenchThick = 5.0;

	HandleLength = 2*JawOD;
	HandleWidth = 25.0;

	//- Build things

	difference() {
	linear_extrude(height=WrenchThick,convexity=4) {
	hull() { // taper wrench body to handle
	circle(d=JawOD);
	translate([0.75*JawOD,0,0])
	circle(d=HandleWidth);
	}
	hull() { // handle
	translate([0.75*JawOD,0,0])
	circle(d=HandleWidth);
	translate([HandleLength,0,0])
	circle(d=HandleWidth);
	}
	}
	translate([0,0,-Protrusion])
	rotate(1*180/NumFlats) { // cosine converts across-flats to circle dia
	cylinder(d=WrenchSize/cos(180/NumFlats),h=(WrenchThick + 2*Protrusion),$fn=NumFlats);
	}
	translate([-StemOD,0,WrenchThick/2])
	cube([2StemOD,StemOD,(WrenchThick + 2Protrusion)],center=true);

	translate([WrenchSize,0,WrenchThick – 3*ThreadThick])
	linear_extrude(3*ThreadThick + Protrusion,convexity=10)
	text(text=str("TE Headset"),size=8,spacing=1.20,font="Arial",halign="left",valign="center");
	}

view raw Tour Easy Headset Wrench.scad hosted with ❤ by GitHub

Now, I’d like to say that was easy, but in actual point of fact …

First, I forgot to divide by cos(180/6) to convert the across-the-flats size to the diameter of OpenSCAD’s circumscribed hexagon-as-circle, which made the wrench uselessly small:

Tour Easy Headset Wrench - v1 — Tour Easy Headset Wrench – v1

If you have a 28 mm nut with low torque requirements, though, I’ve got your back.

While I had the hood up, I slenderized the handle into a much shapelier figure:

Trotting off to the garage with a warm plastic wrench in hand, I discovered the blindingly obvious fact that the headset nuts have eight sides. On the upside, the number of sides became a parameter, so, should you happen to need a five-sided wrench (perhaps on Mars), you can have one.

So, yeah, it’s rapid prototyping in full effect:

Remember, kids, never design while distracted …

2017-09-21

Eyeglasses: New Nose Pads

A stray nose pad appeared on the kitchen floor and, after some investigation, it corresponded with the stub in Mary’s oldest reading glasses. Some rummaging in the Bag o’ Eyeglass Stuff produced a similar pair of pads:

Glasses – missing nose pad

Although the lenses have become somewhat scuffed over the years, masking the optics with Parafilm is always Good Practice:

Glasses – new nose pads – masked

The split boxes clamped around the pad stems required a bit of delicate opening-up with a utility knife blade before the new ones pressed firmly into place.

This was significantly easier than the Silhouette frame repair!

2017-09-17
American Standard Kitchen Faucet: Cleaning and O-Rings

The O-rings on the spout of our American Standard kitchen faucet wore out again; having described that repair many times, there’s no need to say much more about it. I didn’t want to get into this repair while thinking about the hot limit problem, but I did check to make sure the box under the sink had some O-ring replacement kits.

A bench vise with soft jaws holds the spout while you remove the escutcheon ring retainer:

Kitchen faucet spout – in vise

Basically, just tap around the ring with a long drift punch and it’ll eventually fall out onto the reasonably clean rag below it.

The interior of the spout before cleaning shows why you should never look into your plumbing:

Kitchen faucet spout interior – before

After a few hours in a white vinegar bath and a few minutes of scrubbing with a ScotchBrite pad:

Kitchen faucet spout interior – after – 1

Another view:

Kitchen faucet spout interior – after – 2

Obviously, you could do better, but it’s hard to get excited about the last few nodules. For whatever it’s worth, the nodules grow despite our water softener; I have no clue what’s going on in there.

A few wipes of silicone grease, reassemble in reverse order, apply a firm shove, and it’s leakless again. For a while, anyhow.

2017-09-16
RAMPS 1.4 Heatsinking

The knockoff Arduino Mega board actually has eight thermal vias on the copper pour around the regulator:

RAMPS Mega – regulator – thermal vias

I sawed up a clip-on heatsink originally intended for a 14 pin DIP, bent it a bit, and epoxied it atop the regulator with enough of a blob to contact the copper pour:

RAMPS Mega – regulator heatsink – clamping

That’s metal-filled JB Weld for good thermal conductivity and electrical insulation:

RAMPS Mega – regulator heatsink

The blob affixing the heatsink to the crystal can was an oopsie, but won’t do any harm. It’s not clear the heatsink will do any good in that confined space, but those regulators lead a rough life and need all the help they can get.

The five stepper drivers sport HR4988SQ chips, rather than Allegro A4988 chips:

RAMPS – stepper driver – HR4988 chip

I’d rather see a knockoff than a counterfeit, although by now there’s really no way to tell if it’s a counterfeit knockoff. The Kynix datasheet looks like a direct rip from Allegro.

They now sport cute little heatsinks, which, for all I know, might help a bit:

RAMPS shield – stepper heatsinks

The driver boards are slightly longer than the spacing mandated by the continuous socket strips under the three-in-a-row layout:

RAMPS – stepper driver board fit

Introducing them to Mr Disk Sander (turned by hand) knocked off just enough to make ’em fit.

2017-09-06
Garden Y Valve Corrosion: Partial Fix

The corroded Y valve, minus another failed hose fitting, recently emerged from a heap o’ stuff on the Basement Laboratory Bench. This old photo gives you an idea of what happens to cheap pot metal in a garden:

Corroded Garden Y Valve

I dropped it Y-end-down into a container of white vinegar for a week, after which a few minutes of scrubbing produced a workable result:

Garden hose Y valve – after vinegar soak

The threads on the left side are pretty much gone. The hose fitting protected the threads on the right, but was corroded firmly in place; a penetrating oil soak and concerted muttering removed it.

All of the garden hoses and fittings out in Mary’s Vassar Farms plot have survived well beyond their best-used-by date. Given that we salvaged many hoses from the Farm’s end-of-season midden heaps, they don’t owe us much …

The next iteration will have more brass …

2017-09-04
American Standard Elite Kitchen Faucet: Hot Limit Safety Stop Mystery
For the second time in a few months, the kitchen faucet handle stopped moving all the way to the left and the spout stopped dispensing hot water. The last time I did nothing and, after a few days, it resumed normal operation. Having had a while to think it over, this time I removed the handle and saw exactly what I expected:

American Standard faucet – hot limit ring

The installation manual has a useful diagram:

American Standard Elite 4453 4454 faucet – hot limit stop diagram

The red ring (the “hot limit safety stop”) fits into one of eight click-stop positions; the photo shows it in position 5, with 0 being just to the right of the bottom screw and 7 just below the horizontal notch across the middle.

The dark gray plastic feature inside the ring connects the metal handle (the out-of-focus silver stud aimed at you) to the valve assembly. The two lugs sticking out to its left and right bump into the inward-pointing red lugs as you rotate the handle leftward = clockwise = more hot. With the ring set to the 0 position, the red lugs overlap similar lugs molded into the light gray valve body that limit the rotation in both directions.

Observations:
- You must pry the red ring upward to disengage the splines locking it into position
- The gray lugs impose a hard stop in the counterclockwise direction = cold
- There’s no upward force on the ring for any reason that I can imagine
- We don’t pound on the faucet handle, so there’s no shock loading
I have no idea how the red ring could disengage its splines and move counterclockwise by five clicks all by itself.

I reset it to 0, reassembled the faucet with a dot of penetrating oil in the set screw, and it’s all good.

We’ll see how long that lasts …
2017-09-02