Tag: Repairs

If it used to work, it can work again

Bicycle Helmet Mirror Mount: Re-anchoring the Boom

My original dimensions for the helmet mirror mount used three sections of the inspection mirror shaft, with a short length of the fattest tube screwed into the azimuth turret:

Mirror shaft – 2-56 stud

Each section has a pair of brass leaf springs applying just enough friction to hold the next-smallest tube in place, with a rolled crimp securing the springs and preventing the smaller section from pulling out. My first version used that short length of the largest section and the next (for Mary’s helmet) used only the two smallest tubes; it’s rapid prototyping at its finest, except that I rarely discard a prototype that actually works.

Late last year I managed to pull the shaft out of the base while adjusting the length and watched those two springs flutter to the ground beside me.

After finding both of them amid the usual roadside clutter, I swore a mighty oath that I’d epoxy the base of the middle tube into the larger one, eliminating one non-functional adjustment point:

Bike helmet mirror mount – epoxied stalk base

The heatstink tubing covers most of the evidence, but you can see a fillet of epoxy around the end.

Done!

2014-04-28
Water Heater Anode Rod Status

The Whirlpool water heater anode rod is corroding nicely:

Whirlpool anode rod – 2014-04

The new GE water heater anode rod seems to be passivating:

GE anode rod – coated – 2014-04

There’s some corrosion up near the bolt head, so it’s not entirely asleep:

GE anode rod – bolt – 2014-04

I hammered the coating off the rod, scuffed the shiny parts with coarse sandpaper, wiped off the dust, and stuck it back in its socket. We’ll see what it looks like next year.

Both tanks flushed nicely without too much sediment.

Searching for “water heater” will turn up other posts…

2014-04-25
Incandescent Bulb Lifetime

Two 40 W incandescent bulbs in the front bathroom burned out within a few days of each other. Being that type of guy, I know that I installed this bulb nine years ago:

Bulb base – install date

The date is easier to read with the bulb in hand: 13 Feb 05. The (5 yrs) indicates the previous bulb in that socket lasted five years.

The other bulb date went in during March 09, so it survived only five years; the previous bulb lasted 6 years.

Even though 40 W incandescent bulbs are history, maybe I have enough spares on the shelf that the next owner can replace ’em with cheap LEDs.

This may not be science, but it does have numbers…

2014-04-24
V-Brake Replaceable Pad Pins

After replacing the front wheel bearings, I replaced both pairs of brake pads. The rear brakes use holders with slide-in pads, but I’ve never been happy with the dinky little pins that retain the pads, so this time I’m using ordinary cotter pins:

V-brake pads – cotter pin retainer

The rear brake pads on a diamond-frame bike sit nearly horizontally on the seat stays, with the pin head pointed upward. On Tour Easy recumbents, the pads stand almost vertically on the chain stays, with the pins sideways:

Tour Easy rear brakes

That photo dates to 2010, when those brakes were new. Nary a pin has worked loose yet and I don’t expect they ever will, but …

If the pins rust before the pads wear out, I’ll go back to those little bitty OEM stainless pins.

2014-04-23
Eyeglass Bridge Repair

The nose bridge of my “computer glasses” snapped in the exact center, thus confirming my dislike of the springy head-clamping design. These never leave my desk, so I filled a small brass tube with epoxy, shimmed the lenses on a surface plate, tweaked the bridge into alignment with a surface gauge scribe, and let it cure overnight:

Crude nose bridge repair

That layout deliberately reduces the springiness by aligning the lenses to be parallel across the bridge, rather than being a bit side-eyed. They’re an un-bendable alloy that provides no way to tweak the alignment; they emerged just about perfect, but it’s time for a new pair later this year.

FWIW, they’re DIY “computer glasses”: +1 diopter to the far (“infinity”) correction and -1 diopter from the reading adder, producing a pair of glasses with the far point at about 1 meter and an unchanged reading-distance correction. That worked well, but next time I’ll use +0.75 diopter so I can sit back a bit further from those big monitors.

Also: the rust on that lovely surface gauge scribe base came from the previous owner and looks much worse in the picture than in real life. I should run it through an Evaporust bath the next time I have some out. It’s probably a Starrett Model 257, but with absolutely no maker marks whatsoever.

2014-04-22
Bird Nesting Boxes: Cleanout Time

Springtime moves the Bird Box Cleanout chore to the front of the to-do list…

Three different species used this box in succession:

Bird box – stacked nests

Those tiny birds haul all this stuff into the boxes one twig / feather / strand at a time:

Bird box nests

The big branches come from a pick-up-sticks session; we don’t have birds that big around here!

One nest sported a decorative yellow plastic ribbon that the bird surely regarded as a rather tough bit of grass:

Bird nest with plastic strand

They could handle this job on their own, but we think we can reduce the number of parasites by airing out the boxes. We should do the cleanout in the fall to provide nice empty cavities that they can use for winter shelter, but they seem perfectly happy to snuggle together atop the nests in the cold and the dark…

2014-04-20

Revised Thinwall Open Box Calibration Object

Which thinwall open box is better?

Object A:

Thinwall Open Box - Minkowski - solid model — Thinwall Open Box – Minkowski – solid model

or Object B:

Thinwall Open Box - hull - solid model — Thinwall Open Box – hull – solid model

The latter, of course: I blundered the inner corner radius, which occasionally produced little tiny dots of infill that shouldn’t be there. Just one of those errors that hides in plain sight until something else goes wrong, then it’s obvious.

Rather than fix the Minkowski version, I rebuilt it using the hull() operator to shrinkwrap four cylinders for each solid, then remove the smaller block from the larger. Commenting out the hull() operators shows that the cylinders now line up properly:

Thinwall Open Box - un-hulled - solid model — Thinwall Open Box – un-hulled – solid model

The OpenSCAD source code:

// Thin wall open box calibration piece
// Adapted from Coasterman's Calibration set
// Ed Nisley - KE4ZNU - Dec 2011
// Adjust for Slic3r/M2 - March 2013
// Reworked for hull() with correct corner radii - April 2014

//-------
//- Extrusion parameters must match reality!
//  None of the fill parameters matter

ThreadThick = 0.20;
ThreadWidth = 0.40;

Protrusion = 0.1;           // make holes end cleanly

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

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

Height = IntegerMultiple(5.0,ThreadThick);

WallThick = ThreadWidth;

CornerRadius = 2.0;
CornerSides = 4*8;

SideLen = 20.0 - 2*CornerRadius;

Rotation = 45;

//-------

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);
}

//-------

ShowPegGrid();

rotate(Rotation)
	difference() {
		hull() {
			for (i=[-1,1], j=[-1,1])
				translate([i*SideLen/2,j*SideLen/2,0])
					cylinder(r=CornerRadius,h=Height,$fn=CornerSides);
		}
		hull() {
			for (i=[-1,1], j=[-1,1])
				translate([i*SideLen/2,j*SideLen/2,-Protrusion])
					cylinder(r=(CornerRadius - WallThick),h=(Height + 2*Protrusion),$fn=CornerSides);
		}
	}

2014-04-18

Tag: Repairs

Bicycle Helmet Mirror Mount: Re-anchoring the Boom

Water Heater Anode Rod Status

Incandescent Bulb Lifetime

V-Brake Replaceable Pad Pins

Eyeglass Bridge Repair

Bird Nesting Boxes: Cleanout Time

Revised Thinwall Open Box Calibration Object