The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Recumbent Bicycling

Cruisin’ the streets

Tour Easy: Yet Another Shifter Pulley

Somehow, I think I’m never going to get around to doing a CNC version of this thing, but at least now I have more pictures…

The overall problem comes from the fact that the Tour Easy frame geometry doesn’t match the expectations of the front shifter: the cable bends over a small finger that, on a diamond frame bike, should simply hold it in position. Here’s the finger, with a very early version of the pulley that just holds the cable slightly higher than the normal position, complete with one snapped wire showing that the pulley wasn’t getting the job done:

Front derailleur cable with broken strand

The obvious solution involves running the cable over a nice, rounded surface that prevents abrupt bending. The most recent version looks like this:

Shifter pulley installed – left view

Yes, the end of the cable sticks out over the chain; I haven’t tucked it in yet.

A bit of lathe work produces a 0.42 inch diameter thin brass disk with a 50 mil half-circle trench around it; in retrospect, the diameter of the trench bottom should be 0.42 inch and the OD should be about 0.45 inch. If you have really good parting-off-fu, you can produce a disk with a finished backside right on the lathe, but I had to drill an off-center hole anyway, so I thinned it on the Sherline:

Shifter pulley – thinning

It looks like this after all the thinning:

Shifter pulley – thinned

One flange is wider than the other: the thin flange faces front and gets a bunch of cutouts, the wide flange faces rearward and must support the bitter end of the cable.

I lined it up in the shifter, filed a notch to fit around the shifter finger, scribed the hole location, clamped it down, and drilled the hole:

Shifter pulley – center drilling

I think the hole could be on-center with the larger disk; now that I’m keeping better notes, I’ll try that next time. If so, then I can drill it on the lathe, part it off to the correct width, and hand-file the backside flat. The general idea is to have the cable pass over the finger, which almost happens with the smaller diameter.

Some tedious hand-filing produces notches that index over the finger and clear some protuberances on the shifter arm. This is the front face of the pulley that sits against the shifter arm, with a 5 mm socket head cap screw for scale:

Shifter pulley with bolt – front face

The rear face has one side of the trench filed away to get the cable out of the trench and around the bolt:

Shifter pulley with bolt – rear face

Then it looks like this from the right side of the bike:

Shifter pulley installed – right view

A pleasant morning with some Quality Shop Time…

2013-07-14
Public Facilities Maintenance: Lack Thereof

I have a deep and abiding cynicism about the wisdom of building Special Facilities for bicycles and pedestrians. We very much enjoy biking along the Dutchess County Rail Trail, but I fear the County’s initial enthusiasm and funding will quickly wear off, leaving us with another poorly maintained facility.

For example, the section of trail just south of Morgan Lake (a.k.a., Phase II) opened in July 2009, a mere four years ago. This view shows the North Grand Avenue at-grade crossing:

DCRT N Grand – overview

Shortly after the opening, the ADA-mandated vision-impaired tactile pavement strips at that crossing began to deteriorate and, by now, they’re just rubble-filled depressions across the trail on either side of the road.

The south strip:

DCRT N Grand – South ADA Strip

The north strip:

DCRT N Grand – north ADA strip

Evidently, the Official Personnel traversing the DCRT lack the responsibility / authority / initiative to apply a broom and sweep the pebbles out of the path, much less schedule a repair crew. I suppose I should haul a shovel along on one of our trips and privatize the upkeep; it’s been two years, so further waiting will be pointless.

It’s not as though there’s no Official Traffic, as witnessed by this well-worn informal entrance at the south end of that trail segment:

DCRT Overocker – vehicle tracks

There’s an Official Gate just to the left of the trail at that crossing, but, judging from the weeds, it’s evidently easier to stay in the car or truck than get out and unlock the barrier:

DCRT Overocker – vehicle gate

Perhaps pebbles now count as tactile paving.

2013-07-06
Coaxial Power Plug Tip: Extraction Thereof

Another coaxial power plug lost its tip inside a lithium ion battery pack used with the APRS + Voice circuitry on our bikes, as I could barely see at the bottom of the socket:

LiIon Pack – output socket

Rather than cutting the pack apart, I buttered up the end of an intact plug with some ABS solvent glue (a hellish homebrew mixture of acetone and MEK), rammed it into the socket, and held it in place for a minute:

LiIon Pack – undamaged plug insertion

The tip emerged on the first try:

LiIon Pack – rescued plug tip joined

Even better, it cracked off the plug without too much effort:

LiIon Pack – rescued plug tip separated

More solvent glue and a few hours of clamping worked fine:

LiIon Pack – clamped plug tip

That cable is now back in service.

2013-06-30
BOB Yak Trailer: New New Grenade Pin Straps

Somehow, I thought those neoprene O-rings that replaced the grenade pin straps on my BOB Yak trailer would last more than one season, but they’ve already rotted out. A bit of rummaging produced a hank of rubber gasket intended to secure window screen in its aluminum frame, so it’s presumably better suited to an outdoor life than O-rings; it comes without provenance, so I have no idea what it’s made of.

A few snips, a handful of cable ties, and it’s all good again:

BOB Yak Grenade Pins – new strap

But I’m not expecting a decade out of these straps, that’s fer shure…

2013-06-23
Poughkeepsie Waterfront Reclamation

Back in the day, long before the environmental movement got any traction, the Poughkeepsie waterfront along the Hudson River used to be an industrial hotbed. That tapered off and, after a while, only the Dutton Lumber treatment facility remained; they manufactured classic CCA pressure-treated lumber. Quite some years after (IIRC) they went bankrupt and abandoned the facility, various buildings burned and the site seems to be slated for redvelopment into condos and suchlike.

The wisdom of siting condominiums along a tidal estuary, just a few meters above the current waterline and well below the future projected flood stage, seems dubious to me, but, then, I’m not a developer.

Anyhow, a recent ride across the Walkway showed that they’re sealing off the contaminated soil under what was once the lumberyard:

Poughkeepsie waterfront brownfield reclamation – overview

An excavator moves gravel from the barge, which probably came a few miles upriver (or downriver, depending on the aforementioned tidal flow) from the Tilcon quarry at Clinton (no relation) Point, into the dump trucks:

Poughkeepsie waterfront brownfield reclamation – gravel barge

The scale of the operation snaps into focus when you notice the guy standing on the quay:

Poughkeepsie waterfront brownfield reclamation – truck detail

An old joke defines the difference between electrical and civil engineers: electrical engineers build weapon systems, civil engineers build targets…

2013-06-22
LAW Lifetime Member Plaque: Rejuvenation Thereof

The brass plate from this plaque rattled down the basement stairs(*) a while ago:

League of American Wheelmen plaque

As you might expect, the adhesive failed and has been replaced at least once. This time, I drilled a pair of 2-56 clearance holes in the plate, match-marked the wood with a punch, drilled a pair of tapping holes, and put it all back together.

There’s not much to see, but I’m pretty sure that plate won’t fall off ever again:

League of American Wheelmen plaque – detail

The lacquer finish has begun disintegrating, but I wasn’t in the mood to strip-and-restore that. The tile remains firmly affixed; when that falls out, it won’t be pretty.

The LAW long ago morphed into the League of American Bicyclists, after deeming Wheelmen as too gender-specific for the modern era.

(*) We hang plaques, certificates, diplomas, and suchlike on the walls beside the basement stairs. Every time we pass by, it’s an Ego Trip…

2013-02-05
Driveway Drain Pipe Grate vs. Chipmunks

Known to be true: chipmunks love drain pipes!

Chipmunk peering from drainpipe

Obviously, an open pipe attracts rodents.

That didn’t matter with a three-foot pipe attached directly to the downspouts, but, as part of the driveway project, I routed the house storm drains and wall footing drain pipes about 20 feet down from the new retaining wall, with the two joining into a single outlet. There’s a cleanout plug on the storm drain line, but the footing drain consists of about 50 feet of corrugated and perforated tubing that would be just about the finest possible chipmunk habitat.

In principle, one would simply glue a grate into the final fitting and be done with it, but leaves from the gutter will pack behind the grate, so it must be removable. Leaving the grate loose means it’ll pop out at the slightest provocation and, most likely, roll another hundred feet down the driveway into the street.

Rather than coping with that, I drilled a clearance hole in the elbow and tapped a matching hole in the grate:

Drain pipe grate – hole tapping

I have a few white nylon 1/4-20 cutoffs from the bike fairing clamps, so I wrecked the threads on one and jammed it into a black nylon thumbscrew:

Drain pipe grate – thumbscrew

Now, of course, the critters can still climb down the drainpipes from the gutters and set up housekeeping in the plumbing, but I’m not putting grates where I must climb onto the roof to clear them. A chipmunk dropped from two stories will scamper away; I’d never walk again.

We shall see how this works out…

2013-01-28