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
A few years ago, this traffic splitter had a magnificent overgrowth goin’ on:
Eventually, somebody (perhaps the NYS DOT) cut the bushes off at their bases and probably hit them with defoliant to keep them down:
I don’t know that the stems cracked the concrete, but they surely eased the slabs apart.
The signpost had a substantial bush at its base:
It’s tough to keep civilization running ahead of Mother Nature …
No CUPS server setup can be considered complete without sending a print job to the wrong printer:
Which wouldn’t be quite so bad if the printer weren’t ever so much faster than I am:
It turns out an ordinary clothes iron can flatten those pages. Set it to “silk”, spread packing paper on the ironing board to intercept the toner, iron a few millimeters of pages at a time, and feed them back into the printer.
Back in the day, laser-specific printer paper came with a grain arranged so it wouldn’t curl when you fed it into the printer with the proper side up. Those days are gone; I’ve tried both ways and they both curl.
Protip: When CUPS thinks it’s done with the job and the Web interface shows nothing’s going on, it’s handed the job to the server’s printing subsystem, which continues spooling data to the printer. Choking off the bitstream requires one command-line invocation on the server connected to the printer:
cancel -a
A paper jam gives you enough time to figure all that out.
Tweaking a new Manjaro Linux 20.1 installation to share printers and allow remote administration, done while replacing an aging Optiplex desktop box that’s been running unattended for far too long.
Start by installing Manjaro’s printer support package:
pamac install manjaro-printer
In the general section of the default /etc/cups/cupsd.conf file, up near the top:
Listen *:631 # listen on all interfaces
DefaultShared Yes # share the local printers
BrowseWebIF Yes # turn on the Web interface
Allow remote admin:
<Location />
Allow all
Order allow,deny
</Location>
<Location /admin>
Allow all
Order allow,deny
</Location>
Restart the CUPS server:
sudo systemctl restart org.cups.cupsd
And then It Should Just Work.
Somewhere out there, you’ll find his video:
Everybody needs a reason to smile!
Bonus: enough vehicles to keep the signal at Burnett green.
In the unlikely event you were wondering, 287 is the frame number from the video-to-still conversion:
ffmpeg -ss 00:03:30 -i /mnt/video/AS30V/2020-11-09/MAH07624.mp4 -t 20 -f image2 -q 1 'Photo Op - 2020-11-09 - '%03d.jpgAll in all, a fine day for a ride …
Despite successfully drilling holes in a few plastic balls, I wanted a somewhat less terrifying setup than this:
The stiffness of the bike helmet mirror mount suggested a similar clamp would have enough griptivity to immobilize the ball while cutting it in the lathe:
Building the clamp around the lathe’s three-jaw lathe chuck eliminates the need for screws / washers / inserts:
The Ah-ha! moment came when I realized the fixture can expose half of the ball’s diameter for drilling while clamping 87% of its diameter, because 0.5 = sin 30° and 0.87 = cos 30°:
That’s an orthogonal view showing 13% of the ball radius sticking out of the fixture; it’s 6% of the diameter.
Which looks like this in real life:
The socket is offset toward the tailstock end of the clamp (on the right in the picture) to expose half its diameter flush with the surface perpendicular to the lathe axis. The other side necks down into a cylinder of the same diameter to clear the drill bit.
This works nicely until the ball diameter equals the chuck jaw’s 20 mm length, whereupon larger balls protrude into the chuck body’s spindle opening. Although I haven’t yet built one, the 25 mm balls in my Box o’ Bearings should fit, with exceedingly sissy cuts required for large holes.
The fixture doesn’t require support material, because the axial holes eliminate the worst of the overhang. Putting the tailstock side flat on the platform gives it the best-looking surface:
The kerf between the segments ensures the jaws can apply pressure to the ball, whereupon the usual crappy serrated 3D printed surface firmly grabs it.
The fixture is a slip fit on the chuck jaws:
Tightening the jaws shoves them all the way into the fixture’s slots and clamps the ball:
Overtightening the chuck will (probably) compress the ball around the drill, which will (best case) give you slightly oversize holes or (worst case) cause the ball to seize / melt around the drill bit, so sleaze up to the correct hole diameter maybe half a millimeter at a time:
That fixture exposes 9.5 mm = 19/2 of the ball. The drill makes a 6 mm hole to fit the telescoping shaft seen above.
Obviously, you must build a custom fixture for every ball diameter in your inventory, which is no big deal when you have a hands-off manufacturing process. Embossing the diameter into the fixture helps match them, although the scribbled Sharpie isn’t particularly elegant.
The OpenSCAD source code as a GitHub Gist:
| // Lathe Ball Drilling Fixture | |
| // Ed Nisley KE4ZNU 2020-11 | |
| /* [Layout options] */ | |
| Layout = "Build"; // [Build, Show, Body, Jaws] | |
| BallDia = 10.0; // [5.0:0.5:25.0] | |
| /* [Extrusion parameters] */ | |
| /* [Hidden] */ | |
| ThreadThick = 0.25; | |
| ThreadWidth = 0.40; | |
| HoleWindage = 0.2; | |
| function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit); | |
| function IntegerLessMultiple(Size,Unit) = Unit * floor(Size / Unit); | |
| Protrusion = 0.1; // make holes end cleanly | |
| inch = 25.4; | |
| ID = 0; | |
| OD = 1; | |
| LENGTH = 2; | |
| //* [Basic dimensions] */ | |
| Chuck = [21.0,100.0,20.0]; // chuck bore, OD, jaw length | |
| Jaw = [Chuck[LENGTH],15.0,12.0]; // jaw free length, base width, first step radius | |
| JawInclAngle = 112; // < 120 degrees for clearance! | |
| JawAngle = JawInclAngle/2; // angle from radius | |
| WallThick = 5.0; // min wall thickness | |
| Kerf = 0.75; // space between clamp blocks | |
| ClampSides = 8*(2*3); | |
| ClampBore = BallDia/2; // clear bore through clamp | |
| ClampAngle = asin(ClampBore/BallDia); // angle from lathe axis to clamp front | |
| Plate = [ClampBore, | |
| BallDia + 2*WallThick + 2*Jaw.z, | |
| Jaw.x]; | |
| LegendDepth = 1*ThreadWidth; | |
| ShaftOD = 3.6; // sample shaft | |
| ShowGap = 1.5; | |
| //———————- | |
| // Chuck jaws | |
| // Real jaws have a concave radiused tip we simply ignore | |
| module ChuckJaws(l=Jaw.x,r=10) { | |
| for (a=[0:120:240]) | |
| rotate(a) | |
| linear_extrude(height=l) | |
| translate([r,0]) | |
| difference() { | |
| translate([Chuck[OD]/4,0]) | |
| square([Chuck[OD]/2,Jaw.y],center=true); | |
| for (i=[-1,1]) | |
| rotate(i*(90 – JawAngle)) | |
| translate([-Jaw.z/2,0]) | |
| square([Jaw.z,2*Jaw.y],center=true); | |
| } | |
| } | |
| //———————- | |
| // Clamp body | |
| module ClampBlocks() { | |
| difference() { | |
| cylinder(d=Plate[OD],h=Plate[LENGTH],$fn=ClampSides); // main disk | |
| translate([0,0,-Protrusion]) // central bore | |
| cylinder(d=ClampBore,h=2*Plate[LENGTH],$fn=ClampSides); | |
| for (a=[0:120:240]) // kerf slits | |
| rotate(60 + a) | |
| translate([Plate[OD]/2,0,Protrusion]) | |
| cube([Plate[OD],Kerf,2*Plate[LENGTH]],center=true); | |
| translate([0,0,BallDia/2 * cos(ClampAngle)]) // ball socket | |
| sphere(d=BallDia,$fn=ClampSides); | |
| for (a=[0:120:240]) { // legend | |
| rotate(4.5*360/ClampSides + a) | |
| translate([Plate[OD]/2 – LegendDepth,0,Plate[LENGTH]/2]) | |
| rotate([0,90,0]) | |
| linear_extrude(height=LegendDepth + Protrusion,convexity=10) | |
| mirror([0,0,0]) | |
| text(text=str(BallDia," mm"),size=2.5,spacing=1.20,font="Arial:style:Bold",halign="center",valign="center"); | |
| rotate(-4.5*360/ClampSides + a) | |
| translate([Plate[OD]/2 – LegendDepth,0,Plate[LENGTH]/2]) | |
| rotate([0,90,0]) | |
| linear_extrude(height=LegendDepth + Protrusion,convexity=10) | |
| mirror([0,0,0]) | |
| text(text="KE4ZNU",size=2.5,spacing=1.20,font="Arial:style:Bold",halign="center",valign="center"); | |
| } | |
| } | |
| } | |
| //———————- | |
| // Clamp with jaw cutouts | |
| module ClampBody() { | |
| difference() { | |
| ClampBlocks(); | |
| translate([0,0,-Protrusion]) | |
| ChuckJaws(l=Jaw.x + 2*Protrusion,r=BallDia/2 + WallThick); | |
| } | |
| } | |
| //———————- | |
| // Lash it together | |
| if (Layout == "Body") { | |
| ClampBlocks(); | |
| } | |
| if (Layout == "Jaws") { | |
| ChuckJaws(); | |
| } | |
| if (Layout == "Build") { | |
| ClampBody(); | |
| } | |
| if (Layout == "Show") { | |
| ClampBody(); | |
| color("ivory",0.2) | |
| ChuckJaws(r=BallDia/2 + WallThick + ShowGap); // move out for E-Z viewing | |
| color("red",0.4) | |
| translate([0,0,-Jaw.x/2]) | |
| cylinder(d=ShaftOD,h=2*Jaw.x,$fn=ClampSides,center=false); | |
| color("white",0.5) | |
| translate([0,0,BallDia/2 * cos(ClampAngle)]) // ball socket | |
| sphere(d=BallDia,$fn=ClampSides); | |
| } | |
The dimension doodles, including some notions that didn’t work:
Zenni ships their glasses in a snap-close case with a fuzzy insert on the bottom, but after you unpack the cleaning cloth and suchlike, the glasses rattle against the hard plastic top.
Make trial fit prototype from thin cardboard and trace it onto a sheet of craft foam:
The pen, much favored by quiltists, has a white ceramic lead that washes out of dark fabrics. You can find a corresponding dark-lead pen, but I can use an ordinary pencil.
Use different colors for different glasses:
Then walk ninja-style again.
Protip: slip an address label atop the foam so a nice person can reunite you with your glasses, should they slip out of your pocket in the unlikely event you sit down anywhere other than in your house.
For reasons not relevant here, I sent the Beckman DM73 to a good home in Europe. Having some experience with the brutality applied to innocent packages by various package-delivery organizations, I filled a Priority Mail Flat Rate Small Box with a solid block of corrugated cardboard:
One inner layer has a cutout for the manual:
The meter and its leads tuck into form-fitting cutouts:
I bandsawed the cutouts from a block with enough layers for some space on the top and bottom:
After mulling that layout overnight, I made a similar block with the saw cuts on diagonally opposite corners, so pressure on the center of the edges won’t collapse the unsupported sides. A slightly larger meter cutout allowed a wrap of closed-cell foam sheet that likely doesn’t make any difference at all.
With everything in place, the box had just enough space for a pair of plastic sheets to better distribute any top & bottom impacts.
I won’t know how the armor performed for a few weeks, but it’s definitely the best packaging idea I’ve had so far.
Update: After nearly two weeks, the package arrived undamaged and the meter was in fine shape. Whew!
