Posts Tagged Sherline
That’s a genuine 2 mm carbide end mill, poked 1 mm into the key cap, snuggled right up against the front edge.
Two epoxy dabs and some wiping later:
The careful alignment on the F key tells you I did it first; obviously, I should make better fixtures.
The holes could be slightly larger and maybe slightly deeper, but the bearings feel just right.
Indeed, they work so well a ball now distinguishes the far-flung Delete and Backspace keys:
Now, to see how long the epoxy lasts …
The clamp tightening screw is made from butter-soft Chinese steel with a swaged hex socket. As you’d expect, the hex wrench eventually (as in, after a few dozen adjustments, tops) rips the guts right out of the socket.
The screw has a M6×1.0 mm threads, but the thread around the hex recess is left-handed. While I could, in principle, print a 127 tooth change gear, rebuild the lathe’s banjo to accommodate it, then single-point a backassward M6 thread, it’s easier to just use a standard socket head cap screw:
The clamp screw passes through the block at an angle:
Fortunately, the screw is perpendicular to the angled side over on the left, making it easy to clamp in the Sherline’s vise:
Using the laser aligner seemed like a good idea at the time, but the top of the screw wasn’t particularly well-centered on the hole’s axis. I couldn’t screw the left-hand part (with the socket) in from the bottom and center the block near its surface, because then I couldn’t extract the screw before proceeding.
I used a diamond burr to grind out a flat for the screw head:
The flat came from about twenty manual
G2 I-2.5 full-circle passes, stepping down through the hard steel block 0.1 mm per pass, at a too-slow 4000 RPM and a too-fast 30 mm/min feed, with plenty of water squirted from one side into a shop vac snout on the other. The doodle in the background of the first picture shows a first pass at the layout, with the burr centered at X=-2.5; I actually did the grinding from X=+2.5 so most of the passes started in thin air.
The screw head started just shy of 10 mm OD and the burr just over 5.2 mm, so the ensuing 5 mm circles created a flat barely large enough. If the flat were perfectly centered on the screw axis, I wouldn’t have had to grind out another millimeter on the left side (toward the bottom of the tool holder body), but it worked out OK:
The trial fitting also showed the head stuck out ever so slightly beyond the far side of the block, where it would interfere with the blade, so I turned off 0.4 mm off its OD.
If I had a 50 mm SHCS in hand, I’d have used it. Instead, I extended the threads of a 75 mm screw, then lopped off the end to the proper length. I’ll spare you the ordeal, including the moment when I reached for the cutoff tool to shorten the screw. A bag of such screws will arrive shortly, in preparation for future need.
Now the [deleted] cut-off holder works the way it should have from the beginning.
The LM12UU drag knife holder buries the blade ejector pin deep inside the machinery:
So a handle with a pin makes sense:
It’s a variant Sherline tommy bar handle, so there’s not much to say about it.
The dark butt end comes from the traces of the black filament I used for the previous part. Even after flushing half a meter of orange through the hot end, you’ll still see some contamination, even with the same type of plastic. Doesn’t make much difference here, though.
Having won an eBay action for a known-dead Sony DSC-F717 at $0.99 (plus $15 shipping, the seller being no fool), I now have a possibly salvageable camera, a Genuine Sony AC supply, and two more NP-FM50 batteries for about the price of any one of the components.
One battery arrived stone-cold dead, suggesting the camera had been put away with the battery installed for a very long time and they died companionably. The camera still charges a (good) battery, even though it doesn’t turn on, and perusing the schematics suggests checking the power switch, because it’s always the switch contacts. That’s for another day, though.
For the record, the battery status:
The red and green traces come from the two batteries I’ve been cycling through the camera since, um, 2003, so they’re getting on in years and correspondingly low in capacity.
The fourth battery (2019 D, the date showing when it arrived, not its manufacturing date) went from “fully charged” to “dead” in about three seconds with a 500 mA load, producing the nearly invisible purple trace dropping straight down along the Y axis.
Now, there’s a name to conjure with. Turns out Sony sold off its Fukushima battery business a while back, so these must be collectibles. Who knew?
The lower cell is lifeless, the upper cell may still have some capacity. Three pairs of 18500 lithium cells are on their way, in the expectation of rebuilding the weakest packs.
After desoldering the battery tab on the right from the PCB, it occurred to me I needed pictures:
Yeah, that’s a nasty melted spot on the case, due to inept solder-wickage.
Unsoldering the three tabs closest to the case releases the cells + PCB from confinement:
I’m still bemused by battery packs with a microcontroller, even though all lithium packs require serious charge controllers. At least this is an Atmel 8-bitter, rather than 32-bit ARM hotness with, yo, WiFi.
The cells have shaped tabs which will require some gimmicking to reproduce:
Now, if only I could reboot the camera …
A reasonably good silicone-wire multimeter probe set arrived last spring and has worked well enough (I thought, anyhow) for the usual voltage measurements, but recently failed while measuring a small current. We all know how this will turn out, but the details may be of some interest.
Measuring the resistance from tip to plug located the fault to the black probe, after which I poked a pin through the insulation near the plug:
The two leads near the bottom go to my shiny Siglent bench multimeter. Despite their similarity to the failed probes, I’m pretty sure Siglent has better QC (well, mostly).
The probe’s resistance was near zero from the tip (offscreen to the left) to the pin and megohms from pin to plug (on the right). Figuring the wire worked loose, I pulled it away from the plug:
Although I wouldn’t have trusted those probes anywhere near their alleged 1 kV rating, seeing that exposed copper-like substance was disconcerting.
Hacking off the strain relief bushing around the wire got closer to the fault:
And, finally, the problem becomes obvious:
Pulling a black banana plug from the heap, I decided to drill a proper hole to anchor the wire:
Which looked like this afterward:
And produced a strongly mismatched pair:
Ain’t it amazing how much fun you can have for a few bucks, all delivered by eBay? [sigh]
One cannot (or, perhaps, should not attempt to) solder parts to 14 AWG wires seated in a 3D printed battery holder base, so I cleaned up the edges of two polycarbonate scraps:
Then drilled holes to match the strut positions:
The holes fit snippets of the original wire insulation, because, after all, polycarbonate is a thermoplastic, too.
Stretch some copper wire to straighten and work-harden it, add insulation snippets, then maneuver everything in place:
I definitely need a third (and maybe a fourth) hand to hold each part, the solder, and the iron, but at least the wires won’t walk away in the middle of the process.
This seemed appropriate for a day involving toys of all descriptions…
A cast iron stove (most likely a mid-last-century reproduction rather than a Genuine Antique™) emerged from a living room recess:
The line across the lid lifter handle shows where it broke, long ago, likely while being played with. Back then, I’d done a static-display-grade fix with a dab of clear epoxy, but a better repair seemed called for; my repair-fu has grown stronger.
I expected the handle to be pot metal, so drilling a hole in both ends for a music-wire stiffener seemed reasonable:
Much to my surprise, the carbide bit skittered off the surface, leaving fine swarf standing on the end. Turns out the lid lifter is cast iron, just like the rest of the stove!
Given that much of a clue, I aligned the pieces in a pair of machinist’s vises:
Slide apart (the vises stand on a smooth glass sheet; the nubbly side is down), dab silver solder flux on the ends, capture a snippet of 40% silver solder in the gap:
Hit it ever so gently with a propane torch and slide together:
The solder flows at 1200 °F = 650 °C, roughly corresponding to the blue-gray color near the joint. The nice purple (540 °C) on the left shows where I held the flame to start, with yellows (400 °C) on both sides. Good enough, sez I, it’s going to be a static-display exhibit.
Most of the solder went to the back side, so I filed it smooth and buffed off most of the heat coloration with a stainless-steel wire wheel in the Dremel:
A little more wire-brush action left the front side looking good:
As with most of the repairs around here, it simply makes me feel better …
Now, go play with your toys!