Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
It adds a festive touch when done up in orange PETG:
MPCNC – Reinforced Z Motor Mount
The attentive reader will note the missing head of the screw anchoring the mount to the left Z rail. Apparently a #32 drill was a bit too small to let the randomly chosen self-tapping screws thread themselves into EMT; they probably anchored a PCB to the plastic case of a long-forgotten lump of consumer electronics.
It should last long enough for something else to let go …
Two more umbrella struts snapped and required the same repair, but, having drained all the suitable snippets from the Box o’ Brass Cutoffs, some lathe work was in order:
Umbrella strut splint – cutting
I used the carbide insert in the mistaken belief it’d be less grabby, then applied the cutoff tool.
Break the edges, slide splints over the ribs, slobber epoxy on the struts, slide splints into place, apply masking tape for a bit of compression & alignment, and let it cure:
We just scrapped out the old dish drainer, only to find the gadget bin on the new drainer let the measuring spoons fall over and lie along its bottom. After a week of fishing them out from under paring knives, cheese slicers, and suchlike, I gimmicked up a holder:
Measuring Spoon Drainer – installed
One might suggest natural PETG, rather than orange, thereby displaying a shocking ignorance of the MVP concept. We’ll run with orange for the shakedown trials, then build-measure-learn, iterate, and, for all I know, we may even pivot.
A bottom-up view of the solid model shows the trench accommodating the bin lip:
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The MPCNC uses a DW660 Cutout tool as a low-cost spindle for tools with 1/8 and 1/4 inch shanks. It features a tool-free “collet grip” to twist the collet nut against the shaft lock, which is convenient for a hand tool and not so much for a CNC spindle: I find it difficult to get two hands into the MPCNC setup with the proper orientation to push-and-hold two locking buttons, while applying enough torque to twist the collet nut:
DW660 – collet grip
Fortunately, it’s easy enough to remove the collet grip. Remove the collet nut, unscrew the four screws holding the yellow snout in place, then pull the snout straight off to reveal the spindle lock plate:
DW660 – nose cap interior
Capture the spring, slide the spindle lock plate out to expose the snap ring (a.k.a. Jesus clip) holding the collet grip in place:
DW660 – collet grip snap ring
Remove the snap ring, make the appropriate remark, pull the collet grip out of the snout, reassemble the snout in its One Correct Orientation, and you’re done:
DW660 – collet grip removed
The retroreflective tape snippet let my laser tachometer report a top speed over 29 k rpm, pretty close to the advertised 30 k rpm.
If one were fussy, one would 3D print a thing to cover the snout’s open end:
DW660 – snout cover
The original snap ring holds it in place and the fancy pattern comes from octogram spiral infill on the bottom.
The collet nut fits either a 5/8 inch or 16 mm wrench, both of which stick out to the side far enough for a convenient hold while pressing the shaft lock button.
After fartoomanyrepairs, we bought a new Brita pitcher with slightly different, although apparently equally crappy, hinge pins, whereupon I bandsawed the long-failed “smart” filter timer out of the old pitcher’s lid:
Brita pitcher timer – contents
The gray rectangle is the LCD panel showing how long since you last replaced the filter. It died some years ago and, indeed, the CR1616 battery was down to 2.8 V.
However, I think the real failure happened when the black square of conductive foam slipped off the switch contacts under the Reset pushbutton’s stud and went walkabout inside the timer:
Brita pitcher timer – opened
That’s where I found it after sawing the casing open. I think the adhesive side should be stuck to the stud, but we’ll never know.
The new pitcher includes a different indicator with green LED status blinkies for “Standard” (40 gallon) and “Longlast” (120 gallon) filter cartridges and a red blinkie for “Expired”:
Brita pitcher – Filter Life counter
Yeah, purple. For some unknown reason, it cost 10% less than the other colors and we’re not fussy.
This one measures filter use by water volume, not elapsed time, counting the number of pitcher refills by noticing when you open the flip-top lid; the corresponding volume depends on your ability to see a nearly invisible line molded into the lid. Unsurprisingly, Longlast filters cost only slightly less than three times standard ones, so they’re not a compelling value proposition.
The idea behind this gadget surfaced while I was looking for something else and, although the front panel makes my skin crawl, it’s just an adjustable DC power supply:
Let’s say it has the potential to be a DC power supply, although we might quibble about the “Precision” part.
As delivered, it’s a deathtrap. Of course, it’s not UL listed and I didn’t expect it to be.
How many lethal problems do you see?
Tattoo power supply – original AC wiring
For starters, it has a three-wire AC line cord with the green-and-yellow conductor chopped off flush with the outer insulation inside the heatshrink tubing just behind the transformer:
Tattoo power supply – ungrounded AC line
The blue wire is AC neutral, but it really shouldn’t be connected to the finger-reachable outer fuse terminal.
The brown wire is AC line, which goes directly to one power switch terminal. In the event of a hot wiring fault, an unfused conductor touching the case will test the GFI you should have on your bench wiring.
The AC line cord uses some mysterious copper-colored metallic substance that’s about as stiff as music wire:
Tattoo power supply – stiff AC wire
The strands cannot be twisted together like ordinary copper wire, although they can be soldered. They may be copper-plated aluminum, because a magnet ignores them.
After soldering the strands together, they snap when bent:
Tattoo power supply – soldered broken AC wire
Generous strain relief is not just a good idea, it’s mandatory.
After some Quality Shop Time, the ground wire now connects to the case through the transformer’s rear mounting screw, the neutral AC wire connects to the transformer, the hot AC wire goes to the tip of the line fuse, and the fuse cap terminal goes to the switch:
Tattoo power supply – AC line rewiring
I relocated the white LED to the middle of the meter, where it looks a bit less weird:
Tattoo power supply – revised front panel
I have no idea what “Porket indicate” might mean. Perhaps “Precision indicator”?
The right 1/4 inch jack, labeled “Foot”, normally goes to a foot switch you don’t need for a bench power supply, so I converted a length of drill rod into a dummy plug to short the jack contacts:
Tattoo power supply – dummy switch plug
The tip comes from a bit of lathe and file work and the white cap comes from a bag of wire shelf hardware.
A genuine hologram sticker (!) on the back panel proclaims “1.5 – 15 VDC 2 A”, which seemed optimistic. Some fiddling with power resistors suggests tattoo liners (I learned a new word!) don’t draw much current:
4 V @ 1 A
8 V @ 800 mA
10 V @ 600 mA
It can reach a bit over 18 V (pegging the meter) at lower current, so it’s Good Enough for small projects with un-fussy power requirements.
They’re all 01 size pens, with a nominal 0.25 mm line.
Just for fun, a plot done with four sizes of black Sakura pens at Z=-1.0 before the Great Leveling:
MPCNC – Sakura Micron black pen widths
The 005 pen made a nearly rectangular single-pass tour around the perimeter of the plot, so you’ll see it passing through every legend.
The chunky-by-comparison 08 pen = 0.50 mm:
MPCNC – Sakura Micron 08 Black – detail
The 05 pen = 0.45 mm looks much crisper:
MPCNC – Sakura Micron 05 Black – detail
The 01 pen = 0.25 mm:
MPCNC – Sakura Micron 01 Black – detail
The almost-can’t-see-it 005 pen = 0.20 mm:
MPCNC – Sakura Micron 005 Black – detail
If you were doing this for a living, you’d probably use 05 pens, because plotter pens are hard to find.
Original HP plotter pens produced a 0.3 mm trace (with a hard to find un-worn tip) roughly equal to Sakura 03 pens, but I haven’t seen anything other than black at Amazon. There’s apparently a 003 pen with a 0.15 mm line; that’s just crazy talk.
Jamming Sakura pens into a plotter pen adapter for the MPCNC makes little sense, so I should gimmick up a specialized holder with some thumbscrew action to keep them from crawling upward out of the holder.
The Smell of Molten Projects in the Morning 