The Smell of Molten Projects in the Morning
Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Making the world a better place, one piece at a time
What else would you call things that raise the back of a Moonlander keyboard:
The Moonlander comes with two adjustable struts, one for each keyboard half, which should hold the things at whatever angle you like. I put wood blocks underneath for better support, but finally gave up and laid out a quartet of elevators on scrap 3 mm acrylic:
The upper hole is 30 mm from the base and that’s the only one I needed, so they’re even easier to make than they look.
Done!
Being a guy of a certain age with a diagnosis of Low Bone Density, I must increase my calcium intake. Rather than add a few hundred calories a day of calcium-rich food that my waistline does not need, I’ll see what adding 600 mg of calcium citrate can do.
Being a guy of a certain type, I prefer to fill my own capsules, which of course involves Quality Shop Time:
Quite some years ago, for reasons not relevant here, I acquired several of what were called “manual capsule filling machines” from the usual online sources. During the ensuing years, such devices have fallen under the purview of the DEA and vanished from the import market, leaving (AFAICT) one USA-ian supplier.
The key difference between “machines” for different capsule sizes is the plate holding the capsule bodies:
A complete machine includes three other capsule-size-related parts:
In normal use, you put the “shake plate” on the body or cap plate, dump a pile into it, and shake until most of the caps / bodies fall into the holes. Then you manually insert the rest, invert any that fell in backwards, and generally mess around until they’re all properly oriented in their sockets. After filling the capsules, you put the cap + guide plates atop the bodies, press down firmly, and (ideally) produce 100 filled and sealed capsules.
It turns out Size 000 capsules are sufficiently chonky that I have no trouble capping the bodies by hand without those other parts, so making just the body plate seemed Good Enough™. The story might be different for Size 1 capsules.
The external dimensions and screw holes match the original plate, so this one fits the same base:
Make one plate and four spacing clips from 6 (-ish) mm acrylic.
If you can think of anything to do with 100 3/8 inch cylinders of 1/4 inch acrylic, clue me in.
Size 000 bodies are close enough to 3/8 inch that I cleaned up the holes with a step drill for a nicer fit. Perhaps making the plate from 3 mm acrylic would produce better results.
Four springs around the screws in the corners support the plate to allow pressing the caps in place. I adjusted the screws to put the top of the plate at exactly the height of the bodies above the blue base place, producing a smooth surface for scraping suspicious white powder into the bodies:
Iterate filling and tamping until the capsule contents are firm-but-not-overstuffed, then press the plate downward and secure it with the spacer clips:
The clips hold the plate at the proper distance to let the caps slip over the bodies and lock in place. This is tedious, but much faster than doing the entire process on individual capsules one-by-one.
With the caps locked in place, flip the whole thing above a bowl, remove the clips, press the plate against the base, and 100 finished capsules shower into the bowl.
You could build a complete filler without having the blue base plate & springs, but I’ll leave that project to your imagination.
The LightBurn layout as a GitHub Gist:
No, I am not making one for you. :grin:
Having stuck many cork bottoms to many coasters and aligning nearly all of them pretty close, I finally made a fixture to get it right from now on:
A plywood disk anchors four arcs cut from a remnant of acrylic mirror left over from the card-suit coasters, using strips of adhesive sheet cut 1 mm smaller than the arcs:
Stick an arc in place, lay the cork inside the arc, and stick the rest of the arcs around the cork:
Squish the arcs in place overnight with Too Many Clamps™:
In use, peel the paper off the cork, lay it in place, ease the coaster atop it, press firmly, remove the perfectly aligned coaster, then put a stack of them in the overnight clamp to solidify the PSA bond.
Should’a done this long ago …
The Bafang 500C display I installed on Mary’s Tour Easy recumbent has assist level buttons along its left edge:
This required her to take her left hand off the handlebar to fiddle with the assist level and, as it turned out, used her thumb in position causing some distress. Given that changing the assist level happens a lot as we ride, it was time for a change.
So I replaced the 500C with a DPC-18 display like the one on my bike, with the key advantage of putting the buttons on the handgrip:
She preferred a higher position for the buttons than I do, with the PTT button for the Baofeng amateur radio below the housing.
After a few iterations, the throttle moved from the right handgrip to the right end of the handlebar crosspiece on a lengthened version of the mount I conjured for Tee’s Terry Symmetry upright bike:
That location requires a bit of dexterity, but let us move the twist-grip shifter upward on the handgrip where it is more comfortable. She rarely uses the throttle, so we’ll try this for a while.
The DPC-18 has an awkward portrait-mode display with an incredible amount of wasted space, with the side detriment of displacing the blue Camelbak hose. After a few iterations, we settled on a receptacle to catch the mouthpiece without requiring any fancy snaps / clips / fasteners:
The solid model descends from the Zzipper fairing mounts on that same aluminum bar, with the bottle simply jammed into the big hole:
There being no real forces on the holder, I omitted the aluminum load-spreading plate across the top and just epoxied four threaded brass inserts into the bottom part.
Early reports suggest a happier thumb and no problems stashing the hose, so it’s all good.
Up to this point I’ve been making mirror alignment targets entirely on the laser cutter to ensure accurate alignment:
While that works fine, using Dot Mode takes basically forever to chew its way through any nontrivial number of targets.
Now that I have more familiarity with LightBurn’s Print-and-Cut feature, I tried printing the graticules, aligning the sheet, then laser-cutting just the perimeters:
The smaller targets fit neatly into the hole perpendicular to the beam:
The larger ones sit flush on the mirrors at 45° to the beam, so stretching the horizontal scale by 1.414 = √2 makes each tick mark correspond to 1 mm of perpendicular beam offset.
All of which worked surprisingly well, with some caveats.
The first gotcha: ordinary consumer-grade inkjet printers do not have CNC accuracy. The corner targets are on 150 mm horizontal centers and 240 mm vertical centers in the LightBurn layout, but my Epson ET-3830 printer put them on 150×241.3 mm centers. This isn’t unexpected, particularly for laser printers, but it means you must use LightBurn’s scaled version of the P-n-Cut alignment.
I used the upper-right and lower-left targets for the P-n-Cut alignment step, confirming the positioning with a laser pulse putting a tiny hole in the paper:
The lines are 0.5 mm wide and the inner circle is 2 mm in diameter, so my alignment at the upper right is as good as it’s gonna get and the lower left is off by maybe 0.3 mm. While it may be possible to be more accurate, I think half a millimeter is a reasonable error budget for targeting accuracy.
The laser-perforated circles should overlay the inner printed circles after LightBurn applies the P-n-C corrections. That they obviously do not indicates the effect of the small target errors. In any event, the maximum error seems to be 1 mm, which gives you an idea of just how precise P-n-C might be.
The perimeter laser cuts are off by about the same amount & direction as the dotted circle in the adjacent target:
Overall, errors around 1 mm seem possible with careful attention to detail, but expecting anything better than a few millimeters is probably unreasonable, particularly for layouts larger than a Letter size page.
Works for me, though!
The LightBurn SVG layout as a GitHub Gist:
A recent mirror alignment check led to complete failure at the laser head aperture just upstream of Mirror 3:
Those five spots come from the center of the platform and the four corners; they will overlay into a single spot in a properly aligned machine.
Pondering my options reminded me that I intended to build new laser tube support pads, because the ones shipped inside the machine seemed crudely made:
It’s partly disassembled in preparation for the next step.
The chipboard shims underneath the stack are mine, but the OEM pile was unstable even with the screws tightened. The reason became obvious when I took the stack apart:
The bump in the middle of the upper block surrounds the post of the laser tube cradle. It looks like this from the side:
All of the blocks were crudely molded and could not be stacked into a stable pile. The tech who assembled and aligned the machine tightened the screws so firmly that the washers crushed into saddles:
I can do better than that, if only because I’m not on the clock.
The tube support on the right end (toward the beam outlet) screwed into a nice set of threaded inserts brazed onto the floor of the laser compartment.
As far as I can tell, the laser cabinet was intended for a real 60 W tube measuring 1200 mm that would stick out into a box on the side of the cabinet, but would allow the left tube support base (shown above) to screw into a similar quartet of threaded inserts. Instead, it has an overdriven 50 W tube measuring 1050 mm with the left support screwed into four crudely hand-drilled and -tapped holes so far off the centerline as to jam the screws against the front end of their slots in order to get the tube barely into alignment, with the screws on the output side jammed against the rear end of their slots.
To answer a question you may have: the commercial tube supports one might buy from a reputable supplier (or, for that matter, Amazon) are either exactly as wide as the compartment (thus eliminating one degree of freedom) or obviously unsteady, and would surely require drilling more holes in awkward locations.
So, we begin.
The general idea is to make a larger set of blocks fitting another quartet of holes with threaded inserts on the right side of the compartment floor:
On the right, I stuck the bottom block to the shelf with double-sided tape:
Because I was unwilling to:
The alert reader will note the four tapped holes immediately to the right of the new blocks. Those were evidently intended for a center tube support for the longer tube, because the crudely hand-drilled holes hide just out of view to the left of the new blocks.
At the far left of that picture, beyond the two holes probably intended for coolant tubes, you can see one of the four holes with tapped inserts that would match longer tubes, where the 50 W tube has its anode and coolant connections.
The larger blocks I made have a hole accommodating the bulge in the tube cradle to let it slide back and forth as needed:
That seemed easier and less exciting than attempting to flycut the bottom of the OEM plastic tube cradle.
The chipboard layer serves as a guide to keep the tube cradle lined up, with its now much shorter screws into the brass inserts epoxied into the plywood layer.
I glued the top layers together to get a rigid assembly, with the lower layers being replaceable shims adding up to the right height, whatever that might be. The LightBurn layout has an assortment of useful pieces, some of which I didn’t need:
If this were a greenfield project, the leftmost Base MDF pad would come in handy, as its slots are large enough to clear the flat side of the 4 mm rivnuts I’d install in the compartment floor.
Thin shims come from paperboard boxes & chipboard:
Thicker spacers come from (scrap) plywood and MDF:
Skipping ahead a few days, the tube & mirror realignment came out much better:
That’s only the four corners of the platform, but it’s OK by me.
If you’re fussy, the scorches are all low by a bit under 2 mm. Fixing that requires raising the tube by 2 mm, which I can certainly do, but I’m going to let this whole affair mellow out for a while.
The LightBurn SVG layout as a GitHub Gist:
After struggling with pin pliers again, I finally made a pin wrench for the laser cutter’s mirror retaining rings:
The odd grayish tint toward the flat end of the knob comes from residual black filament in the hot end after switching to retina-burn orange PETG.
The solid model looks about like you’d expect:
The pins are snippets of 3/32 inch = 2.4 mm steel rod with ground-round ends to fit the 2.5 mm pin sockets in the retaining ring.
They’re rammed into place with a drill press to keep them aligned with the holes:
Pressed flush with the central boss that aligns the wrench with the ring:
Then put the ring on the bench, set the wrench atop the ring with the pins in the sockets, and press firmly to seat the pins to the proper depth. The end results should look like this:
The next time I clean the mirrors, there will be less muttering.
The OpenSCAD source code as a GitHub Gist:
| // OMTech laser cutter mirror pin wrench | |
| // Ed Nisley – KE4ZNU – August 2023 | |
| // From https://www.thingiverse.com/thing:4146258 | |
| use <knurledFinishLib_v2_1.scad> | |
| /* [Hidden] */ | |
| ThreadThick = 0.20; | |
| ThreadWidth = 0.40; | |
| HoleWindage = 0.2; // extra clearance | |
| Protrusion = 0.1; // make holes end cleanly | |
| inch = 25.4; | |
| //———————- | |
| // Dimensions | |
| /* [Knob] */ | |
| PinDia = 2.4; // pin diameter | |
| PinOC = 20.5; // … on-center spacing | |
| PinDepth = 10.0; // … hole depth | |
| LocDia = 14.5; // central stud | |
| LocLength = 3.0; | |
| ShaftDia = 26.0; // un-knurled section diameter | |
| ShaftLength = 15.0; // … length | |
| KnurlDia = 30.0; // diameter at midline of knurl diamonds | |
| KnurlLen = 20.0; // … length of knurled section | |
| /* [Hidden] */ | |
| KnurlDPNom = 32; // Nominal diametral pitch = (# diamonds) / (OD inches) | |
| DiamondDepth = 0.5; // … depth of diamonds | |
| DiamondAspect = 2; // length to width ratio | |
| KnurlID = KnurlDia – DiamondDepth; // dia at bottom of knurl | |
| NumDiamonds = ceil(KnurlDPNom * KnurlID / inch); | |
| echo(str("Num diamonds: ",NumDiamonds)); | |
| NumSides = 4*NumDiamonds; // 4 facets per diamond | |
| KnurlDP = NumDiamonds / (KnurlID / inch); // actual DP | |
| echo(str("DP Nom: ",KnurlDPNom," actual: ",KnurlDP)); | |
| DiamondWidth = (KnurlID * PI) / NumDiamonds; | |
| DiamondLenNom = DiamondAspect * DiamondWidth; // nominal diamond length | |
| DiamondLength = KnurlLen / round(KnurlLen/DiamondLenNom); // … actual | |
| TaperLength = 0.75*DiamondLength; | |
| KnobOAL = ShaftLength + KnurlLen + 2*TaperLength; | |
| //———————- | |
| // Useful routines | |
| module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes | |
| Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2); | |
| FixDia = Dia / cos(180/Sides); | |
| cylinder(r=(FixDia + HoleWindage)/2, | |
| h=Height, | |
| $fn=Sides); | |
| } | |
| //- Build it | |
| difference() { | |
| union() { | |
| render(convexity=10) | |
| translate([0,0,TaperLength]) | |
| knurl(k_cyl_hg=KnurlLen, | |
| k_cyl_od=KnurlDia, | |
| knurl_wd=DiamondWidth, | |
| knurl_hg=DiamondLength, | |
| knurl_dp=DiamondDepth, | |
| e_smooth=DiamondLength/2); | |
| color("Orange") | |
| cylinder(r1=ShaftDia/2, | |
| r2=(KnurlDia – DiamondDepth)/2, | |
| h=(TaperLength + Protrusion), | |
| $fn=NumSides); | |
| color("Orange") | |
| translate([0,0,(TaperLength + KnurlLen – Protrusion)]) | |
| cylinder(r2=ShaftDia/2, | |
| r1=(KnurlDia – DiamondDepth)/2, | |
| h=(TaperLength + Protrusion), | |
| $fn=NumSides); | |
| color("Moccasin") | |
| translate([0,0,(2*TaperLength + KnurlLen – Protrusion)]) | |
| cylinder(r=ShaftDia/2,h=(ShaftLength + Protrusion),$fn=NumSides); | |
| color("Brown") | |
| translate([0,0,KnobOAL – Protrusion]) | |
| cylinder(r=LocDia/2,h=(LocLength + Protrusion),$fn=NumSides); | |
| } | |
| for (i=[-1,1]) | |
| translate([i*PinOC/2,0,KnobOAL – PinDepth]) | |
| rotate(180/6) | |
| PolyCyl(PinDia,PinDepth + Protrusion,6); | |
| } |
It descends from a long line of similar things dating back to the OG Sherline Speed Wrenches.
