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: Improvements

Making the world a better place, one piece at a time

Workbench Drawers vs. Desk Keyboard Tray

The workbench originally in Mary’s Sewing Room became my new desk, which meant installing my pull-out keyboard / trackball tray in place of its drawers:

Desk keyboard tray – top view

Which required re-gluing the old wood strips of the side slides to their backing plates, as they’d worked loose over the decades:

Desk keyboard tray – regluing edge sliders

I drilled & screwed three more threaded wood inserts into the bottom of the bench top to hold brackets (cut from those longsuffering maple library shelves) for the side slides:

Desk keyboard tray – bottom view

The gray angle brackets came from a long-gone (and sorely missed) radial arm saw, hacksawed to fit on either side of the central beam supporting the workbench top, and held with machine screws in those inserts. Yes, the rear bracket has only a single screw, but it doesn’t support much of a load and it’s not going anywhere.

With that in place, the drawers kicked around the basement for a few weeks and eventually ended up under a workbench that Came With The House™ and was likely built by the original owners half a century ago:

Desk keyboard tray – workbench drawers installed

The top is made of 2×6 boards, now topped with laminate planks (left over from when I re-floored the previous kitchen), so the 2×6 board in the middle holds the whole top together and is not removable. I conjured strips at the ends to support the drawer assembly:

Desk keyboard tray – workbench drawers end block

The strips came from the crate around the laser cutter, so they’re made of the cheapest Chinese plywood and entirely suitable for the purpose. The drawers hang from 1/4-20 bolts screwed into tee nuts recessed in the top surface of the strips, with the strips held by deck screws in those benchtop 2×6 planks.

Yeah, both of those are bodges, but they ought to work just fine.

2024-05-03
OMTech Laser Cutter: Honeycomb Rivnut

The honeycomb platform in my OMTech laser cutter was secured by a pair of M4 screws passing through the surrounding frame into a pair of nuts requiring considerable contortion to install. As a result, I tended to use the screws as locating pins by just dropping them into the holes, which didn’t prevent me from jostling the honeycomb out of position on a few occasions.

With everything torn down as part of the move, I drilled out the holes in the frame and installed a pair of M4 rivnuts:

OMTech laser – Honeycomb screw rivnut

The scar around the hole in the honeycomb came from the factory; I have no idea what they were doing to cause that much wear.

Anyhow, installing the screws now requires zero contortionism and they locate the honeycomb much more securely.

I should conjure knobs for the top of the screws to eliminate the need for a hex key, although that’s definitely low on the task priority list.

Update: Like this:

Honeycomb screw knob

2024-04-30
Laser Water Chiller: Heating
The previous Basement Laboratory generally stayed above 60 °F = 15 °C, so I set the LightObject water chiller’s low-temperature alarm accordingly.

Having reached the point where I can set up the laser in its new home, I connected the chiller tubes, filled the reservoir with distilled water (and a squirt of algaecide), connected the alarm wiring, turned it on, and had the cool water trigger an alarm:

LightObject Laser chiller – low temp alarm

Which was relayed to the controller:

KT332N Diagnostic display – water protect active

Silencing the chiller’s alarm clears the error indicator in the controller, so it’s possible to Fire The Laser with too-cold water if necessary.

As with the previous icemaker chiller, plotting the water temperature as a function of time shows the pump adds some energy as it moves the water around the loop:

LightObject Q600 chiller – water heating

The gap in the data shows where I had a few other things to do, but the exponential rise is obvious. The chiller compressor starts at just over 21 °C and stops at just under 20 °C, so the exponential curve had gone about as far as it could go.

The numbers in the upper right of the plot give the weight of:
- An empty water bottle
- A full gallon bottle
- The partially empty bottle used to top off the reservoir
- How much water went into the chiller reservoir
The figures in the bottom mash the initial slope of that curve together with the weight of the water to find the 21 W required to heat the water at that rate, with a bank shot off British Thermal Units because why not.

A Kill-a-Watt meter shows the Q600 chiller draws 36 W with the pump running, which includes the controller and a column of blue LEDs behind the water level tube.

The pump (in the lower right) isn’t exactly water-cooled, but it’s not losing a lot of heat through that foam wrapper and maybe most of the heat really does come from the motor:

LightObject Laser chiller – right side internal view

The basement temperature will rise as Spring becomes Summer, so the chiller will start working right away, and it’ll definitely get more exercise when the laser starts cutting again.
2024-04-29
Novus Polish vs. Fairing Fragment

A fairing fragment provided an excuse to practice plastic polishing:

Fairing polish – start

That’s from a EZR-SZ Zzipper fairing ridden about 2000 miles a year since 2001, so it’s spent far too much time in the sun and definitely not gotten all the finicky care it deserves. It’s tinted 60 mil polycarbonate, vacuum-molded into the bubble shape required to fit on a Tour Easy recumbent.

Fairing Flashlight Mount – Mary approaching

On the other paw, Karl Abbe (the guy behind Zzipper) says the typical fairing survives maybe half a decade, so it doesn’t owe us anything.

I applied all three bottles of Novus Plastic Polish in descending numeric order, using snippets of Official Polish Mates (which could be a Krakow escort service) with a vigorous circular motion, ending up with a reasonable result:

Fairing polish – transmission

I cut the smaller chunk from the fairing for comparison. It’s been washed to dislodge loose crud, but is otherwise as-ridden.

The fairing has deeper scratches than Novus can buff out, but removing the surface scuffs and haze definitely improves the clarity:

Fairing polish – clarity

The view from father away:

Fairing polish – clarity

Eks describes this sort of thing as a “Used Car Finish” = high polish over deep scratches:

Fairing polish – surface finish

All in all, a nice result from very little effort.

The canonical Novus Polish application is removing the haze from plastic headlight covers, but our decade-old Forester is a garage queen and the headlights remain in fine shape.

2024-04-18
SJCam M50 Trail Camera: Battery Wire FAIL

My SJCam M50 Trail Camera has had its share of problems, including water making it past the seals to corrode some connections:

M50 Trail Cam – contact corrosion

I thought cleaning that mess up would solve an intermittent power problem, but the camera continued to fail immediately after being deployed and finally refused to work at all.

The camera case has eight (!) AA cells in one half connected to the electronics in the other half by a pair of wires that pass through the hinge between the halves:

M50 Trail Cam – pivot wire route

The steel rod is the hinge pivot, with the battery half wearing brown and the electronics half in lighter plastic. As you’ll see in a bit, the rod is fixed in the electronics half and the battery half pivots around it.

The two short case sections on the right contain the two wires carrying the 6 V battery power. Some gentle manipulation suggested the fault lay inside those hinge sections, which meant I had to figure out how to get them apart.

The other end of the steel rod has a knurled section jammed firmly into the electronics half, but I managed to carve away just enough plastic to expose just enough of the knurl to get just enough of a grip (yes, with a pair of genuine Vise-Grip 10WR Locking Pliers, accept no substitutes) to yoink the rod out:

M50 Trail Cam – extracted pivot

With the hinge released, the problem became immediately obvious:

M50 Trail Cam – failed hinge wires

Yes, those are wire strands poking out of the hole in the left hinge section.

A tedious needle-nose tweezer session extracted the remains of the wires from the hinge and cleaned out the adhesive:

M50 Trail Cam – extracted OEM PVC wires

Although those two hinge sections are hollow with plenty of room for the wire, it seems the assembler squirted adhesive into both sections to glue the wires in place. As a result, every time I opened the case to charge the batteries, maybe two millimeters of wire twisted 180° degrees. The wonder is that it lasted as long as it did.

I snaked a pair of 20 AWG silicone-insulated wires through the hinge sections:

M50 Trail Cam – silicone rewiring

The OEM wires had PVC insulation, which is a terrible choice for wires that will undergo lots of flexing, but that’s what SJCam used.

Two untidy blobs of acrylic caulk do at least as good a job of sealing the case openings as the black gunk visible in the earlier pictures:

M50 Trail Cam – new caulk

I left all of the wire in the hinge un-stuck, hoping the twist will distribute itself over maybe 5 mm of wire and last longer.

In anticipation of future repairs, however, I left enough of the knurled end of the hinge rod exposed to get an easy grip:

M50 Trail Cam – restaked pivot

Solder the new wires to the old pads, assemble in reverse order, and it works as well as it ever did:

The alert reader will note I did not reset the camera clock after charging the batteries, a process requiring the janky SJCam app.

The two finches on the right have been constructing a nest in the wreath hanging at our front door. They tolerate our presence, although they’d be happier if delivery folks dropped packages elsewhere.

2024-04-05
Packing Tape Dispenser Annoyance: Fixed!

So I bought a packing tape dispenser (“gun”) for the 4 inch wide clear tape over the box labels, only to find the frame projected beyond the rubber roller on one side:

Packing tape dispenser – projecting edge

That steel flange prevented the roller from making firm contact with the box and pressing the tape into place. I’d never seen such a thing on any of the other tape guns I’d used, including a similar one (for 2 inch tape) on loan from the good folks at archive.org:

Packing tape dispensers

Well, even with the shop in disarray, I can fix that:

Packing tape dispenser – filed edge

Filing that bump down definitely improved my disposition over the next few hundred boxes …

2024-04-05
Skil Cordless Driver Re-batterying
In anticipation of upcoming disassembly & reassembly tasks, I finally replaced the long-dead NiCd battery in an old Skil cordless driver with an 18650 lithium cell from the Basement Warehouse Wing:

Skil Cordless Driver – 18650 cell overview

A USB charge controller sits in a slot carved into the plastic formerly supporting the NiCd battery’s charging jack:

Skil Cordless Driver – USB charger detail

Hot-melt glue holds everything in place.

The motor draws about 2 A under full load, which is a bit more than the charge controller wants to supply. I simply wired the motor (through its reversing switch) directly to the 18650 cell terminals, which is certainly not good practice, but seems reasonable given the intended use case.

A red LED shows the charger stuffing energy into the cell:

Skil Cordless Driver – charge indicator

You can see the blob of glue holding one of the acrylic cylinders left over from the gelatin capsule filler; only 99 more to go! I had to turn it down by about a millimeter, an operation best left to your imagination.

After an hour, a green glow shows the cell is fully charged:

Skil Cordless Driver – full charge

The original label proudly touted the NiCd battery’s 2.4 V, so I figured truth in packaging required a new label:

Skil Cordless Driver – new label cutting

The process:
- Scan the original labels
- Blow out the contrast to make binary masks
- Trace into vectors with LightBurn, simplify & clean up
- Add targets for Print-and-Cut
- Save as SVG, import into GIMP, lay out text, print
- Cut the outlines
The labels have laminating film on the top and craft adhesive on the bottom, both of which cut neatly and look pretty good:

Skil Cordless Driver – lithium in action

The alert reader will note the 4+ V from a fully charged lithium cell exceeds the 2.4+ V from fully charged NiCd cells, which accounts for the very bright incandescent headlamps. I figure 4 is roughly equal to 2.4, for large values of 2.4: the driver ticks along at 170 RPM instead 140 RPM.

I measured the torque using a double-ended hex bit in a torque screwdriver, with the torque setting cranked up until the driver just barely clicked it over.

I took the liberty of filing the raised “2.4 V” off the hinge covers and adding tidy retroreflective disks:

Skil Cordless Driver – hinge cover

I briefly considered adding “3.7 V” (because “4.2 V MAX” wouldn’t fit) in laser-cut PSA vinyl, but it was getting late.

Now I can screw things up in style …
2023-12-01