The need to gnaw a V groove into the side of two 60 mm aluminum bars led to this Sherline CNC mill setup:
Milling the near end of the bars put the angle plate’s rear lock screw within a millimeter of the column; the vise fits in exactly one spot on the angle plate and that’s where the jaws must be.
While controlling the mill with the Joggy Thing and some manual command entry, because it’s easier than real CNC programming, I overshot the near end and rammed the column with enough enthusiasm to dislodge the Y-axis leadscrew nut. An interlude of utter confusion ended with the backlash preload nut firmly jammed against the leadscrew coupler on the other end of travel:
The paper shreds show where the bellows formerly stuck on the Y axis stage.
The backlash nut chewed off a few star lock gear teeth on its way out, as seen here just above where they mesh:
It’s been quite a few years since I took the thing apart to replace the nuts, so I used the opportunity to lube the otherwise inacessible X axis leadscrew inside its table upside down on the bench.
The setscrew locking the Y axis leadscrew nut in place heaves into view with the X axis table off:
I thought about jamming it in place with a second 10-32 setscrew, but the ones on hand were just an itsy too long and collided with the X-axis table:
The thought of having the additional setscrew work loose, grind into the underside of the table, and require major surgery for recovery persuaded me to drop it back in the drawer.
With everything in place, I adjusted the backlash (on both axes) down to a few mils:
Tweaking the X axis preload nut under the table is not my idea of a good time, but it’s been quite a while since I had to do that.
Folding the new paper bellows and installing them took about as long as repairing the mill.
Milling the second V groove worked fine; all is right with the Sherline again.
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:
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:
The blades sport a few nicks from their previous life, but work well enough.
Word has it the 16 year old son was driving, with his father in the passenger seat, and managed to lose control without any of the usual causative factors. Everyone lived to tell the tale, which is a tribute to the contemporary auto tech we all take for granted.
Contrary to what we thought, they crashed around 8 pm and Central Hudson cut the power around midnight to repair the lines.
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:
Brutal surgery removed the LED and installed a replacement:
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:
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:
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.