Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
(The last three digits in the caption tick along at 60 frame/s. Opening each iamge in a new tab will let you embiggen the details, although the images aren’t all that great.)
The second wingbeat, over on the left, is more visible as the hawk lifts off:
Hawk with snake 2025-11-04 – 112
This was about when I figured out what was going on:
Hawk with snake 2025-11-04 – 151
A hawk can easily outfly me!
Hawk with snake 2025-11-04 – 207
The snake dangling from the hawk’s talons didn’t see it coming, either:
Hawk with snake 2025-11-04 – 213
Up and away!
Hawk with snake 2025-11-04 – 225
About 2.3 s of elapsed time: plenty for a hawk and not nearly enough for me. Or the snake, for that matter.
Mary’s zero-mph crash loosened the starboard handlebar plug enough to let it eventually decamp for parts unknown. Its replacement, a somewhat fancier aluminum plug with an expanding cone retainer using an actual M3 nut, worked fine for the last year, but Mary recently noticed the socket head screw had worked loose.
In the interim, I’d moved the Bafang thumb control from its original position on the crossbar to just above the rear shifter:
Tour Easy – right handlebar control stack
Which moved the clamp on the shortened grip off the end of the handlebar tube, so I flipped the grip around, tightened the clamp, and installed the plug.
Unfortunately, the grip ID is 4 mm larger than the tube ID, which meant the plug’s cone retainer was struggling to hold on in there. Perhaps the plastic cone has relaxed bit, but I figured giving it more traction would be a Good Idea™ before I declared victory:
Handlebar Grip Sleeve – PrusaSlicer
It’s a little plastic sleeve with slots to let it expand against the inside of the grip:
Handlebar grip sleeve – installed
Yes, it’s sticking out slightly; you can see the corresponding gap up inside next to the tube.
A wrap of double-sided sticky tape glues it in place as the retainer presses it against the grip ID and a dot of low-strength Loctite should keep the screw from loosening again.
The OpenSCAD source code:
// Handlebar grip sleeve
// Ed Nisley - KE4ZNU
// 2025-10-25
include <BOSL2/std.scad>
/* [Hidden] */
ID = 0;
OD = 1;
LENGTH = 2;
HoleWindage = 0.2;
Protrusion = 0.1;
NumSides = 3*2*4;
$fn=NumSides;
Sleeve = [18.5,22.0,14.0];
Kerf = 1.0;
difference() {
tube(Sleeve[LENGTH],id=Sleeve[ID],od=Sleeve[OD],anchor=BOTTOM);
for (a=[0,90])
zrot(a)
up(Sleeve[LENGTH]/4)
cuboid([2*Sleeve[OD],Kerf,Sleeve[LENGTH]],anchor=BOTTOM);
}
Based on someearlieritems, I’d been printing TPU at 220 °C, but 230 °C fuses the threads together:
Terracycle Chain Idler Tire – correct settings
The filament turned out to be 1.79 mm diameter, rather than the nominal 1.75 mm, and a few iterations showed a 0.95 Extrusion Multiplier worked much better.
Those were printed at 30 mm/s with 0.25 mm layer height.
I now have a good stock of spare tires, each slightly different than all the others:
Terracycle Chain Idler Tire – spares
The first two slightly delaminated printed tires will remain in service until they show signs of falling apart, because I’d rather ride the bike than fiddle with it.
The Terracycle (now T-cycle, for reasons presumably involving the transfer of money) chain return idlers on our Tour Easy bikes developed hardening of their urethane tires:
Terracycle Idler tire – printed vs OEM
Urethane shouldn’t crack like that, but after more than fifteen years, stuff wears out.
The white ring is 95A TPU printed on the Makergear M2, which is definitely more flexy than the original tire, but has the redeeming feature of being both Good Enough and trivially easy to model:
include <BOSL2/std.scad>
NumSides = 4*3*2*4;
$fn=NumSides;
Thick = 3.5;
ID = 46.4;
OD = ID + 2*Thick;
Length = 11.2;
tube(Length,id=ID,od=OD,anchor=BOTTOM);
It printed with 5 mm brims on both the ID and OD, because TPU has the barest adhesion to the M2’s glass plate + hair glue. There’s a long-unopened box now on the bench with a BuildTak PEI surface (thank you: you know who you are!) that should improve the situation.
In any event, the tires fit well:
Terracycle Idler tire – installed
The layer-to-layer adhesion isn’t as good as I think it should be, so I’ll likely use those tires as testcases for tweaking the new build plate & settings.
A long-lost repair finally made it to the top of the list:
Bicycle Mobile – bottom view
The original string had long since rotted out, but everything else was in a plastic bag just waiting for this occasion.
The colorful cylinders are stacks of laser-cut 6 mm disks with a 2 mm hole, held to the wire & string with a tiny dot of high-viscosity cyanoacrylate glue at each end:
Bicycle Mobile – detail
The disks came from acrylic leftovers:
Bicycle Mobile – laser-cut acrylic
The motion you can’t see makes the shiny bikes much more visible out there:
The weight ball had a 2 mm hole filled by a wood plug which I cleaned out piecemeal with a 1.5 mm drill bit in a pin vise; a short length of wood skewer holds the new string in place.
Because the upper arms support more weight, their disk stacks need fewer disks for the same leverage. The original mobile had (at most) four 6 mm chromed plastic balls at each level, so I started with eight 3 mm disks, adjusted the stack length as needed, glued them in place, then removed the surplus disks by crushing them with a Vise-Grip.
The bushes & trees along the Dutchess Rail Trail were reaching out to touch us again, so I took some slow rides with many stops.
Maple Oak trees along Page Park Drive:
DCRT Brush Trimming – oak – 2025-07
Blackthorn encroaching through the fence at Overocker:
DCRT Brush Trimming – blackthorn – 2025-07
A tree somebody tossed down the trail bank near Morgan Lake:
DCRT Brush Trimming – discarded tree – 2025-07
The slide lock on my trusty rehabilitated Fiskars bypass pruner worked loose and began sliding into the LOCK position when held overhead, then fell apart during disassembly:
Fiskars pruner – lock rebuild
The lock now consists of:
An M4 × 12 mm nut from a Chicago Screw that exactly matched the 5 mm OD cylinder passing through the pruner body
A laser-cut fluorescent acrylic disk for thumb grippiness
A washer just because
An M4 hex-head screw
A dab of Loctite bonding screw to nut
Clean the blades with alcohol and it’s ready for the rest of the season.
I should have put a wave washer in the stack for some springiness, but it works surprisingly well for what it is.
Now: discover how long acrylic lasts out there in the wild.
Update: Yeah, the lock needed a wave washer for more friction, which became apparent after the first overhead branch.
The Smell of Molten Projects in the Morning 
