Friday, March 9, 2018

The way it goes

I wanted to install a ceiling fan where there was only a ceiling light.  No problem!  I've done this many times before - maybe 30-45 minutes is plenty.


As so often happens in projects, this one snowballed and wound up taking over 3 hours.  Follow along with these easy-to-repeat steps and see if you can tell where the problem lies:

Step 1 - Remove the old light fixture

  1. finger screws for the glass bowl -- easy peasy.
  2. a screw or two holding the light housing to the junction box -- boy, this box is pretty wiggly.
  3. the wirenuts and ground wire connecting the light to the supply -- hot wire is off; all is well.
Pro tip: It's a good idea to turn off the breaker, but chances are good your breakers are labeled incomprehensibly or are outright lies.  What I do is turn off the room switch and then quickly tap the hot wire with a finger to see if i get zapped.  I didn't this time!

Surprise! A pleasant surprise!  The power supply run to the light is actually 4 wire romex ("12-3"), which is convenient for fans (one hot for light, one hot for fan, one neutral, one ground).  There was only one switch in a one-gang box, but hey - somebody was thinking ahead.

Surprise! An unpleasant surprise!  While fiddling with the wiggly box, I got zapped by the white wire.  That's bad - the white wire shouldn't be hot... not with the switch off, not with the black and red being unpowered.  Investigation required.

In any case, to hang a fan I'll need to reinforce the box - I can inspect the wiring when i get up in the attic.  The box was using one of those metal hangers that span between the two joists, but it seemed to be quite loose.

Step 2 - Reinforce the ceiling box

Up in attic (getting to the area above the box was a challenge to begin with!) I found that the hanger hardware was poorly installed.  Each side had metal brackets with three holes for nails, but each side was only held on with loose staples.  I pulled them out and put in screws (easier than nails in this case).  That cut down a lot of the wiggling, but it still twisted more than i'd prefer, and i didn't want the fan rocking, so...

I cut a 2x4 to the width of the cavity and screwed it in - some of the angles were pretty hard to get to, but i did it... slightly crookedly.  So i reattached the junction box with some shims to make up the difference.  Perfect!

Step 3 - Run new wires between the ceiling box and the wall switch

Luckily i had an extra length of romex laying around.

Step 4 - Replace the wall switch with a 2-gang box and wire new switches

Luckily I had some extra old work junction boxes and switches laying around.  I'm not sure what was causing the white wire to be hot, but when i was done all was well.  Something must have been shorted in the switch box before i pulled it all out and rewired.

Step 5 - Install Ceiling Fan

Connect the new wires, attach the new base to the ceiling box, connect the blades.  Test (all went fine).


Aspiring do-it-yourselfers beware: this is a disturbingly common occurrence.  Not always ceiling fans, but houses are generally built by drug-crazed vandals.

To answer the question at the beginning: "see if you can tell where the problem lies" the problem was the existence of steps 2,3, and 4.  Ideally you'd only need 1 and 5 (but only 1 of the 3 ceiling fans i did in this batch was actually like that).

Saturday, December 30, 2017


 Ronny and Matt from Church invited some youth to try simple forging.  Ronny brought an anvil and some know-how.  Matt brought a little propane forge.
Starting from some simple rod stock, a couple guys each got to pound on the red hot metal:
to make a stylish little letter-opener:
 I got to hammer too, and made a wee "garlic cleaver":
I didn't do much of the metal - i just supplied some dumb hammering while Ronny moved the work - but I was proud of the handle:

I cut off 5" of an oak branch that had fallen during the recent storm, shaped it with a rasp, then burned it with a blowtorch to get the color.  I sealed it with a quick clear coat spray.  The handle only took about 90 minutes (mostly the rasp), and I was pleased with the comfort and color.

I mounted it on the blade by drilling a hole in the wood (slightly undersized for the tang), heating up the metal to really hot, and shoving them together.  The hot metal burned its shape into the wood and it's holding quite well.

I would definitely do the burned wood again.

Sunday, December 24, 2017

stained glass triakis icosahedron

It was hand-made from cut glass (score and snap), bound in copper foil (rather than lead came), and soldered with 60/40 (tin/lead) solder.The lighting is provided by strip of LED lights - it consumes little power, and could be supplied by a wall adapter or computer’s USB port.I find the shape to be both aesthetically and mathematically pleasing.

On the Making

First make a a lot of uniform isosceles triangles (at least 60, probably more if any turn out badly).  I made mine about 2.5 inches tall and 1.5 inches wide (a very poor-man's golden ratio).
  1. Bind all their edges in copper foil tape, solder the borders
  2. Solder them all together so internal dihedral angles are all exactly 138.189685°
  3. I made a little jig out of coat hangers and hot glue to help get the angles right.
  4. Before closing it up, shove an LED light strip in there.

coat hanger jig calibrated to exactly 138.189685°

On the Triakis Icosahedron

The shape can be seen as a platonic icosahedron with triangular pyramids augmented to each face.


An icosahedron is a polyhedron with 20 faces, 30 edges and 12 vertices. There are many kinds of icosahedra, with some being more symmetrical than others.The best known (and the one this star builds from) is the Platonic, convex regular icosahedron, which has five equilateral triangular faces meeting at each vertex.


Adding a triangular pyramid to each face of a polyhedron, making a particular Kleetope.


In three-dimensional space, a Platonic solid is a regular, convex polyhedron. It is constructed by congruent (identical in shape and size) regular (all angles equal and all sides equal) polygonal faces with the same number of faces meeting at each vertex. Five solids meet those criteria:
Four faces
Six faces
Eight faces
Twelve faces
Twenty faces


Video of lights in action

Saturday, December 23, 2017

Hearth finale... finally

The top veneer of newer concrete never really hardened into a surface I could polish.  It remained weak and grainy, so I scraped it all back off:
In removing the little PVC segment i'd used to cast a hole for the gas key, I chipped more of the surface.  Vexing!

I gave it some sanding afterward, but because I'd given up on it looking "nice" I didn't go beyond 200 grit polishing (and I had pads going up to 3000!).

I called friends to help me carry it (300+lbs) inside.  I had to cut a bunch of the wood to get it to fit right -- the standard approach of measure once, cut 5 times -- but it's in.  I didn't wind up gluing or shimming it at all -- it's pretty solid.

This was a frustrating project, but the flaws aren't as offensive in person as I feared they would be.  They're less obtrusive than I'd feared, and all through christmas people were sitting on the hearth, so you couldn't see them anyway.

The overall effect is fine -- I'm not in a huge rush to replace it like I thought i'd be.  I could do this one a LOT better if i were doing it a second time around.

Notes to future self doing a similar project:

  • casting it in place is a bad idea -- this is a messy operation.
  • casting upside down on melamine worked well.
  • make sure the form is well-supported - the weight will want to bow the form.
  • mortar (as a material rather than true concrete) is fine.
  • reinforcement could probably be the heavy wire mesh instead of rebar, probably doesn't matter.
  • wet polishing is awesome, don't dry sand it.
  • I couldn't tell if additives did anything at all.

Monday, December 18, 2017

Hearth Update

Follow-up to the recent follow-up: After casting the hearth and grinding out the flaws, and then leveling the depressions with cement slurry, I was unsatisfied with the resulting variation in color and texture:
(I know i could make the polisher lines go away, but the major blotches weren't going to "buff out").

So my mother and I built a new form around the existing block:

and poured (this time right-side-up) and troweled some new mortar (one batch for consistent color).  I tried really hard to get it reasonably smooth and pit-free, but tolerated some bumps (which i could later sand down).
 It poured well, but unfortunately in my haste I tried to sand it again before it was sufficiently cured.  Worse, I did it in a highly visible area.  Because of the cold, two days was not enough (even with a space heater in the garage), to get it to sufficiently harden.  I mangled it pretty severely.  Very sad.  I think i'm done trying to make it perfect now -- we'll see good i can make it look when it's ready for sanding.
 Vexed at my inability to make progress on the heart itself, I returned to the box it will sit on, which has just been 2x4s.  With some help, I added tile board:

And then put some ledger tile on it.  I actually just used construction adhesive, since i had some laying around and the area wasn't that big.  The rock snippets came already glued into larger panels, i just had to cut them to shape.   The wife kindly got some prefab corners which made it a lot easier to look nice (although the corner pieces are pretty tricky to cut to size).

Pretty happy with the look here.  A little concerned about overshadowing it with a hideous concrete slab.  We'll see.

Robot Arm - sprockets and challenges

Robot Arm


Received and deployed the chain and sprockets:
  • Now using a 3:1 reduction on the bottom of the arm (which bears the most strain), and use my 270 degree servo for that (giving me a 90 degree effective range, and converting my 20kg-cm to ~60kg/cm).
  • using a 2:1 reduction on the middle of the arm.
  • using 1:1 sprockets for the rotation.
Chains and Sprockets!  
Largest (48 tooth) gear at bottom of arm,
 middle size (32 tooth) in the middle joint
smaller (16T) on the servos (and on the underside to rotate the arm)


I don't have a chain breaker, and that part was a lot harder than I imagined.  I pounded the pins out on my vise with a hammer and nailset, a nail, and a broken drill bit... just like the pros.

I had trouble with a 3rd servo.  I traced through the various issues and determined it was particular to one of the "channels" I'd built to power the servos.  I tried a billion combinations of wires, and found that it was specifically the hot supply in channel #3.  It wasn't the power supply itself, and it still failed after i resoldered my home-made connections, so that left only the store-bought regulator.  My multimeter said it was giving good voltage and amperage, but it worked when i replaced it with a different one.  No idea what's wrong with it.

I burned out my raspberry pi.  As you can probably see in the pictures, my work area is a disastrous mess with tools and supplies and pieces and waste from of a bunch of projects all over it.  I think i nudged the pi so that the pins on the underside shorted on a metal washer.  It immediately died and won't boot.  It was a foolish waste of $30 and time i could have tinkered - i should keep cleaner, but i also need to juggle multiple projects.


Waiting on a new Pi to arrive, but with upcoming family events and the ongoing hearth saga, I may not have much time to work on it in the next week and a half.

Even so, the sprockets are effective, and the arm has enough strength so far.  Long may it last.

smooth as silk.

little distractions

A little light on project updates lately because:
  1. had a baby
  2. house lost power in a storm and i had to move out for a few days
  3. same storm threw large branches around the yard, crushing fences and breaking off my gutter and fascia.

So I have been:
  1. Dandling said baby
  2. Cooling heels and watching football at a friend's house for a while
  3. Replacing fascia, putting banged-up gutter back into place
  4. Chainsawing up fallen tree-matter.
But even so I've made some progress - other updates to follow.