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.

Tag: Laser Cutter

Improvised Table Leg Latch

While setting up the small table I conjured from scrap, I discovered one of the folding legs no longer had a latch to keep it from folding. Whether it never had one or the latch got lost along the way, there’s no time like the present:

Table leg latch – installed

The bolt I put there in place of the joint rivet precludes a smaller latch along the lines of the simple steel loop on the other leg, so I figured I may as well go large and, with that much surface area, plywood will work just as well as steel for my simple needs.

It’s a topless, bottomless box from the infinite supply at boxes.py, here seen with its halves being glued at right angles on an aluminum bracket:

Table leg latch – gluing

When those set, I glued & clamped them together in situ, then wrapped the whole mess with what’s basically high-strength friction tape to encourage it to not come too far apart under the inevitable stress when the leg tries to fold with a pile of stuff on the table.

We’ll see how long this survives; if past experience is any guide, it’ll be a while.

The WordPress AI image generator has a shaky grasp of both human anatomy and the blog topic:

Woodwork design by Escher. What is that interesting tool? So many arms, all with nightmare fuel anatomy!

2024-05-31
C-Power KK-800A Calculator Dress Panel Re-gluing

Long ago, I got Mary a cheap “desk calculator” with a vital function: it beeps cheerfully with each keypress. Nothing lasts forever and the aluminum dress panel around the keys has been gradually working its way loose.

So, we begin …

Gingerly remove the panel, un-bend and flatten it, lay it on the scanner, and cover with black paper:

C-Power calculator keyboard cover

Blow out the contrast, threshold the image, do a little touchup, and get a binary mask:

C-Power calculator keyboard cover – mask

Import into LightBurn, trace and discard the image, do some shape optimization, add 0.2 mm to the height & width of one key, propagate those dimensions to other keys (Make same width and Make same height FTW), cut a paper prototype to verify the fit, iterate until it drops neatly into place, cut an adhesive sheet, then peel & stick:

C-Power KK-800A keyboard – adhesive placed

The dress panel was held in place by what was once a quick-setting gooey glue that had long since fossilized. Although it gave up on the aluminum, it was not going to come off the calculator body without more struggle than seemed warranted.

So I stuck the new glue atop the old glue and hoped for the best. You can see traces of the old glue bead through the sheet:

C-Power KK-800A keyboard – adhesive ready

Lay the dress panel in place, burnish between the rows & columns, and it looks about as good as it ever did:

C-Power KK-800A keyboard – restored

If the adhesive sheet also gives up on the aluminum, I’ll try some fancy 3M 300LSE adhesive.

The WordPress AI image generator heard I like keys, so it spat out some keys for my keyboards:

Calculator keyboard – WP AI image

The piano keys seem familiar, the thing in the middle looks eerily like a PDP-11 front panel, and … could that be a folding keyboard in the distance next to an 8-track player from a car dashboard?

2024-05-27
Magnifying Desk Light: LED-ifying & Base Refooting

My ancient fluorescent magnifying desk lamp emerged from a box and cried out to be used, but the equally ancient 22 W fluorescent ring light was long past its prime and cried out to be replaced with something from the current millennium.

So I removed the fluorescent ballast / choke from the junction box at the lamp base:

Magnifying Ring Light – ballast removed

That’s a grounded outlet in the cover plate serving as a wire termination block. The red crimp connector joins a white wire that formerly went to the ballast with the black wire going to the lamp head; you’ll note the black wire from the line cord going into the same heatstink tubing at the outlet.

The lamp head had a push-to-start switch, presumably with an internal starting capacitor or some such, but also sporting a pair of terminals behaving like a single-pole push-on / push-off switch. A bit of rewiring, of which there are no pictures, made it work perfectly with the new 13 W LED ring light:

Magnifying Ring Light – LED ring installed

It now sits on a bit of laboratory ironmongery weighing about as much as a small child:

Magnifying Ring Light – on base

Although the base has four feet, it sits perfectly flat on my (admittedly battered) surface plate because all four feet have been ground to make that happen:

Magnifying Ring Light – foot plan view

Those feet will be hostile to any table / bench top outside their intended laboratory environment. Fortunately, the geometry is simple enough to build directly in LightBurn and cut from a cork disk with PSA backing suited to become a coaster:

Magnifying Ring Light – cork foot cutting

Which fit well enough, although all four feet are just slightly different:

Magnifying Ring Light – cork foot

The new Basement Shop™ is coming together and this stuff is getting easier …

The WordPress AI came up with a plausible steampunk build:

Magnifying Ring Light – WP AI image 1

Love those flowy feet, although the vertical rod in the back seems misplaced.

Adding “one-piece base” to the prompt produces contemporary style:

Magnifying Ring Light – WP AI image 2

Dunno what the dingus on the lower arm might be (perhaps a spring?), but it’s got the right general idea.

2024-05-23
Plywood Clamp

Being in need of a dedicated clamp, I made one from Thingiverse:

Plywood clamp – overview

The original gets its clamping force from a gazillion rubber bands, but two wraps of shock cord joined by the guts of an electrical crimp connector worked for my simple needs:

Plywood clamp – shock cord crimp connector

The rounded tips work at any thickness, but introducing them to Ms Belt Sander set them for the specific purpose I have in mind:

Plywood clamp – flatted tips

The little cork pads are hand-cut from scraps, because why not.

Rubbing paraffin (wax, not kerosene) on the circular joint’s bearing surfaces makes the hinge move soooo smoothly.

The WordPress AI image generator is trying much harder:

Plywood clamp – WP AI Image

The callouts almost make sense, because they’re now ripped from the post text. For sure, I will “crustorilize” my next shop project.

Gotta love the AI evaluation:

The content shows a practical and creative approach to making a plywood clamp, supported by clear images. Consider adding a brief introduction to provide context for the project. Additionally, explaining the specific purpose for which the clamp is intended would further engage readers. The use of humor and informal language adds a personal touch, enhancing the connection with the audience. Overall, the engaging content and visual aids make it a compelling read.

2024-05-22
Laser Cutter: Streaming Camera Support

If I’m making something with the laser cutter during a Zoomed SquidWrench meeting, switching the view to a camera inside the cabinet is always a crowd-pleaser. Having tried several locations with various degrees of success, the camera now sits atop a small chipboard box holding it as high as it can get over the front left corner of the platform:

Laser camera support box – position overview

It juuuust barely kisses the head in that corner:

Laser camera support box – near collision

The box is a simple ClosedBox from boxes.py with a jawbreaker URL full of parameters, minus two holes, plus a quartet of shims, all cut from chipboard:

Camera Support box – LB layout

The holes fit a 1/4-20 button head screw for the Logitch C615 camera’s tripod mount and the hex wrench needed to tighten it:

Laser camera support box – interior

The box is held together with Genuine Scotch Tape, because I want it to fall apart if it gets hit by the laser head. It’s held to the cabinet with a finger-crushingly strong bar magnet.

The camera has a reasonably good view of the entire platform:

Laser Cutter – USB Camera view

The camera’s closest focus point sits about halfway across the platform, roughly corresponding to the typical monitor-to-face distance the camera was intended for, but it’s Good Enough™ for the purpose.

2024-05-21
Harbor Freight Bar Clamp: Plywood Handle

After only a dozen years, one of the 3D printed replacement handles for my Harbor Freight bar clamps snapped exactly where you’d expect:

HF bar clamp – plywood handle

The replacement this time around is laser-cut plywood, with a pair of 3 mm sheets glued together to just about match the original thickness:

HF bar clamp – plywood handle gluing

I hacked the OpenSCAD code to use its projection() operation to export the outline of the solid model on the XY plane, inhaled the SVG into LightBurn, replaced the original chunky hole with a Real Circle, cut a pair of them, discovered I messed up the diameter, tweaked that, cut a pair that fit perfectly, and that was that.

Flushed with success, I cut another pair to replace the (not yet failed) handle in the other HF bar clamp and restarted the failure clock.

Not as fancy as something milled on the Sherline, but way easier and, if it lasts another decade, I’ll call it a win.

The WordPress AI had fun with this post:

HF Bar Clamp Handle – WP AI image

The thing over on the left must be a 3D printer, but what’s floating in the middle? Those hand tools look downright scary.

2024-05-20
Prince Ping-Pong Table Surface Leveler

Mary redesignated the Prince Tournament 6800 ping-pong table that Came With The House™ as her quilting layout table, so it now fills much of the Sewing Room (f.k.a. the Living Room):

Mary with quilt on ping-pong table

For reasons lost in the table’s history, the two halves of the top surface weren’t quite flush on one side, by a matter of a few millimeters. This bothered me far more than it did her, so the delay until I finally fixed it wasn’t critical:

Prince ping-pong table leveler

That’s 3 mm plywood + 1.5 mm Trocraft Eco pushing the surface upward just enough to almost make the joint (visible near the bottom of the picture) flush within +2 -1 mm across the table width, making it obvious that neither piece is exactly planar.

The shape has mixed metric and inch dimensions, for no reason I know:

Prince ping-pong table leveler

If you ever need such a thing, remember to use screws about 4 mm longer than the ones you took out.

The LightBurn layout as an SVG image:

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view raw Prince ping-pong table leveler.svg hosted with ❤ by GitHub

2024-05-10