The Smell of Molten Projects in the Morning
Ed Nisley's Blog: shop notes, electronics, firmware, machinery, 3D printing, and curiosities
Cruisin’ the streets
Yeah, this is enough to knock your bike completely off course:
The black smudge matches a scuff on the right sidewall of the front tire. I think I hit it in that orientation and it pivoted clockwise while lifting the bike and shoving the tire to the left.
Another look from what was likely the right side of the shoulder:
I’ll give it a decent burial out back … and be glad our roles aren’t reversed!
We’re southbound on Rt 376, ticking along at about 15 mph, with fresh string-trimmer debris littering the shoulder:
Did you notice the rock? I didn’t.
The fairing ripples as my front tire hits the left side of the rock:
I have no memory of the next two seconds.
The offset impact turns the front wheel to the left, so the bike steers out from underneath my weight:
Because the bike frame was still aimed straight ahead, the wheel is steering further to the left and putting me even more off-balance. I am somehow trying to lean left far enough to get my weight lined up with the bike:
One second into the event, Mary has no idea what’s going on behind her.
My memory resumes with an image of the yellow midline just beyond my left foot:
Mary heard an odd sound and asks (over the radio) “Are you all right?”
I’m approximately balanced, turning toward the shoulder, and manage to shout “NO!”:
I’m coasting toward the shoulder with my feet off the pedals:
Mary is stopping and I coast past her:
Landing gear out:
Back on the shoulder, lining up with the guide rail:
Dead slow:
Docking adapter deployed:
And stopped:
I sat in that exact position for nearly four minutes.
A slideshow view of the same images so you can watch it unfold:
Doesn’t look like much, does it?
If I could have looked over my shoulder, this is what I would have seen, starting at T = 0 with the rock impact blurring the image:
Surely scared the daylights out of that driver, perhaps confirming all the usual expectations of crazy bicyclist behavior.
Here’s what Mary would have seen over her shoulder, again starting at T = 0 with the fairing bulging from the impact:
Timing is everything.
That Benz is new enough to have automatic emergency braking, as it slowed pretty dramatically while I was busy getting out of the way, but it’s not clear whether AEB knows about small / lightweight targets like pedestrians and bicyclists.
We completed the ride as planned, although I finally realized the front fender bracket had broken a few miles later.
Every adult human male has at least one story beginning “But for that millisecond or inch, I wouldn’t be here.” Now I have one more.
I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain.
Frank Herbert, Dune
The mudflap on my front fender rides low enough to snag on obstacles and the most recent incident (about which more later) was a doozy, breaking the left strut ferrule and pulling the bracket off its double-sticky foam tape attachment. Fortunately, the repair kit now has plenty of duct tape.
The replacement printed up and installed just like its predecessors:
Having the bracket be the weakest link makes perfect sense to me …
Every now and again, an upshift to the large chainring on my Tour Easy would go awry and drop the chain off the outside, where it would sometimes jam between the pedal crank and the spider. In the worst case the flailing chain would also jam in the TerraCycle idler, but I fixed that a while ago.
Contemporary chainrings (i.e., anything made since the trailing decades of the last millennium) generally have a chain drop pin positioned against the crank specifically to prevent such chain jamming.
Making a chain drop pin is no big deal if you’ve got a lathe and an M4 tap:
A closer look:
That’s a 10 mm length of 5/16 inch brass rod drilled with a recess to fit the head of a 10 mm M4 socket-head cap screw.
The pin should be a micro-smidgen shorter, as it just touches the crank, but, if anything, moving the chainring inward by one micro-smidgen improved the upshifts and I’m inclined to go with the flow.
Should’a done it decades ago …
A little more than two years after replacing its internal battery, the SJCAM M20 camera on my Tour Easy once again wouldn’t last to the end of the driveway if I forgot to turn on the external battery pack. This time around, the camera was so firmly jammed in the printed seat frame mount that I had to cut the mount apart.
Yup, that puppy is all swoll up:
Poor thing looks like a tiny pillow:
While I had it apart, I tried to clean / refurbish the button contacts on the top. Unfortunately, they’re pretty well buried in the camera frame and I was unwilling to dismantle the optics, remove the display, and gut the camera to find out if they were more accessible from the back surface:
While all that was going on, I ran off a new mount in white PETG:
I’m down to the last battery. The “4.35V” on the pillow indicates they’re special high-voltage lithium-polymer cells, so I can’t just drop a random lithium pouch cell in there and expect it to Just Work.
I think the “782633” is the cell size, so, if I were willing to have a few thousand on the shelf, a 552525 pouch might fit. The reduced capacity wouldn’t be a problem, as it must just keep the camera’s clock ticking between rides.
Drat!
Over the course of a few days, my Tour Easy recumbent developed a slight squeak that turned into a definite creak, then the seat started shifting slightly under hill-climbing forces. Of course, no force I could apply in the garage caused the slightest squeak / creak / motion. A decade ago this was due to a sheared screw at the dropout, but everything seemed to be in good order.
So I applied a drop of penetrating oil to each of the many joints in the seat hardware, went on a few more rides, and eventually the seat started moving with normal pedaling forces.
The left strut clamp looked fine:
OK, it looks grubby. I’d rather ride than lick my bike clean.
The right clamp definitely showed signs of motion:
I extracted the strut assembly, degreased the clamps, reinstalled in reverse order, replaced the nuts, snugged everything down, and it’s all good again:
Yeah, I should have replaced those screws, but I didn’t even have to take the wheel off, sooooo …
Having run the Newmowa NP-BX1 batteries through my old Sony HDR-AS30V helmet camera a few times, a plot seemed in order:
The cluster of dots shows most of our rides last about an hour.
The line is an eyeballometrical fit, slightly coerced to pass through the origin because that’s where it should go.
The 9.1 mA·hr/min slope is in reasonable agreement with past results, given different batteries and charger. The Keweisi meter emerged first from the box.
Straining the hr/min dimensional nonsense out of the slope suggests the camera averages 550 mA and 1.9 W. Derating those by a few percent to account for the recharge efficiency might be in order, but they’re surely in the right ballpark.
The Smell of Molten Projects in the Morning 