Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
For reasons that should be obvious by now, I volunteered to rebuild a wheelbarrow used at the Vassar Community Garden plots. It spent all its time outdoors and one of the handles eventually broke off:
Wheelbarrow rebuild – old handles
I’d already removed the wheel and front strap, which were in good condition.
The new handles were undrilled, so I marked and drilled them with a nice brad-point bit to get clean holes:
Wheelbarrow rebuild – handle drilling
The metal “barrow” had cracked around the carriage bolts holding it to the frame, so I filed a quartet of fender washers to fit the square section under the heads:
Wheelbarrow rebuild – fender washer holes
After a false start, I marked the bolt heads and washers to line them up properly while tightening the nuts on the other end:
Wheelbarrow rebuild – fender washer installed
One front strut had gone missing, so I replaced it with a mashed-and-drilled section of ski pole:
Wheelbarrow rebuild – front strut
All in all, a few hours of Quality Shop Time interspersed with a few pleasant bike rides to various local stores, wherein I learned who doesn’t stock the necessary hardware.
Protip: Home Depot has the highest-entropy hardware assortment.
For the record, all the bolts have a 5/16-18 thread.
Mary found a rusted Fiskars bypass pruner in the trash pile near her Vassar Farms plot and brought it home for proper disposal. The nuts and screws responded to an overnight penetrating oil treatment and it came apart easily:
Fiskars bypass pruner – as found
The movable jaw may have once sported a PTFE coating, but it’s likely just a different steel alloy.
After scrubbing the pieces with an abrasive pad, a little diamond filing, and (at the insistence of the Squidwrench chorus) some Dremel wire-wheel action, it looks almost new:
Fiskars bypass pruner – restored
The blades sport a few nicks from their previous life, but work well enough.
The cut is just in front of the PCB and went slowly to avoid clobbering the SMD resistors very near the edge.
The cataract turned out to be crud adhered to the LED lens:
Side Marker E – LED cataract
Brutal surgery removed the LED and installed a replacement:
Side Marker E – replacement LED
The PCB had two 150 Ω SMD resistors for use with 12-ish V automotive batteries. While I had the hood up, I removed one and shorted across its pads to make the LED work with the 6 V switched headlight supply from the Bafang motor.
In round numbers, 6 V minus 2.2 V forward drop divided by 150 Ω is about 25 mA. The original LED ran at 35-ish mA, but it’s close enough.
Glue the lens back in place:
Side Marker E – clamping case
The bubbly stuff is solid epoxy from the original assembly, which is why removing the PCB is not an option.
The new LED is no more off-center than any of the others:
Side Marker E – new LED – front
It does, however, sit much closer to the lens, due to the ring of plastic I cut away to get inside. As a result, the beam is mostly a single centered lobe with only hints of the five side lobes; there isn’t much waste light from the side of the LED into those facets.
The Bafang battery charger uses an AC line cord “binocular” connector with what must be the weakest spring contacts ever made, which finally annoyed me enough to fix:
Bafang charger – AC line cord anchor
Also, the case now sports four thick fuzzy felt feet to keep it from sliding around quite so easily.
Another customer-does-the-last-ten-percent product …
With the Bafang BBS02 and all its gimcrackery on the Terry Symmetry buttoned up and ready to go, I took a few closeout pictures for future reference.
The motor has a sheaf of wires sticking out of the bottom crying out for a protective covering:
Bafang BBS02 – wire bundle cover
Although cameras tell only the truth they’re allowed to see and can be made to lie by omission, sometimes their latent truth was completely invisible to eyewitnesses in real time.
I only noticed the mis-routed shift cable when I looked through the last set of pictures.
It should pass through the plastic channel under the metal tab holding the cable guide to the bottom bracket shell:
Bafang BBS02 – wire bundle vs shift cable
Normally, aiming the cable into the channel is no big deal. In this case, I had to undo the shift cable, remove the left crank, loosen the motor and rotate it out of the way, nudge the cable with a small screwdriver, then reinstall in reverse order.
The original BBS02 reaction spacer for Gee’s Terry Symmetry didn’t work quite the way I expected:
Bafang BBS02 – reaction block displacement
The motor evidently vibrates enough to propel the block forward, shearing the double-sticky foam tape which was never intended to resist force in that plane. I thought the block was located at the point where the motor casing was tangent to the frame tube, so as to equalize the forces in both directions, but … nope.
A revised design based on measurements informed by new knowledge:
Terry – Bafang motor spacer – improved – solid model
The upper curve is now symmetric and the whole block mounts more rearward under the bottom bracket lug, where some tedious work with a machinists square located the real tangent point:
Bafang BBS02 – reaction block improvement
The motor sure doesn’t look like it’s tangent, but a dry fit showed all the curves laid against the case and tubes.
The brazing fillet means the step fitting the downtube can’t sit snug against the edge of the lug, but most of the reaction force should go through the section into the lug, near the center of the block.
A crude marker will keep track of any motion:
Bafang BBS02 – reaction block marker
I think the symmetric curve against the motor has enough projection to keep the block from wandering off, even if I haven’t gotten the location exactly right.
The Smell of Molten Projects in the Morning 