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.

Category: Machine Shop

Mechanical widgetry

Sears Sewing Table: Foot Repair

While arranging the venerable Sears Sewing Table in its new abode, we found the casters underneath didn’t roll nearly as well as they should, which turned out to be due to an accumulation of damage:

Sears sewing table – torn MDF

As far as I can tell, all four casters have been displaced upward, probably because they have no support directly above their stems and any force applied to the wheel has plenty of lever arm against those screws.

The MDF panels on the outside of the table have pictures of wood laminated to their surface, but lack enough structural integrity to keep the screws in place. The plywood, however, survived largely unscathed, although the screws were pulling out.

I poked as much wood glue into the gaps as possible, then applied as many clamps as possible, with wood strips on both sides of the bulge squashing the MDF into a flat sheet. Over the course of two gluing sessions (I need more clamps!) spanning three days, while Mary really wanted to start sewing, the glue cured. I had plenty of time to unbend the brackets and put a more-or-less right angle between their two screw plates.

Rummaging in the box of laser scraps (after finding said box) produced disks cut from various projects that fit between the plywood bottom of the cabinet and the stems:

Sears sewing table – repaired foot – side

The brackets deliberately don’t match their original shape, because their new squareness put the screws into undamaged spots in the MDF and plywood:

Sears sewing table – repaired foot – bottom

The MDF will never be quite the same, but it’s flat on the visible side and the glue (seems to have) consolidated the fragments well enough.

Although those wheels look terrible, the bracket now holds the stem vertically and all four of them roll easily and pivot smoothly.

The laser-cut disks are held in place by pure faith and the overwhelming weight of all the MDF in the table, so they’re not going anywhere. Because the table’s weight now rests on the caster stems, as distributed across the plywood cabinet bottom through the disks, the brackets shouldn’t be subject to excessive upward force.

She started therapy right away:

Sears sewing table in use

And we continued moving in …

2024-04-08
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
Little Fairy Electric Sparklers

From back when “electric” was the new hotness:

Little Fairy Electric Sparklers – box front

The back of the box gets downright multilingual, although there’s no English-language mention of “magnesium” anywhere on the box:

Little Fairy Electric Sparklers – box back

Little Fairy Electric Sparklers – box right

Little Fairy Electric Sparklers – box left

They are most assuredly not electric, which means they have no batteries to corrode and they still work fine:

Little Fairy Electric Sparklers – test firing

They emerged from a box of my father’s memorabilia, most likely packed away by his parents, so they date back to the early part of the previous century. The American Sparkler Company is long defunct, but the Internet never forgets.

You can (maybe) buy sparklers or concoct your own. I donated the remainder to our Young Engineer, who promised to dispose of them in a safe manner.

2024-04-04
Magazines to the Archive

Thanks to tantris aiming me in the right direction, my techie magazines are on their way to the Internet Archive for scanning:

Archive boxes – A

They’re also accepting our 14th Edition of the Encylopædia Britannica (back when folks realized global war was a thing, but before knowing the recently concluded horror was the first), two dozen Tom Swift Jr books (largely responsible for much of the rest of my life), three years of LIFE magazines from the mid-1940s needing no further description, and a few other goodies:

Archive boxes – B

They want boxes packed as solidly as possible to withstand shipping & warehousing, so I converted nearly all of my scrap cardboard into bracing and padding:

Archive boxes – cutting gridwork

The grids are Tray Inserts generated at festi.info:

Archive boxes – internal bracing

Here, try one yourself:

TrayInsert – sample QR code

That will set up a grid filling the gap between two stacks of magazines in the Archive’s standard 12×18×8 inch box. You’ll also want simple rectangles for the sides & tops, but those are easy.

They preferred the laser cutter’s inevitable campfire smell to smashed boxes full of crumpled magazines. AFAICT, you might be able to crush the box, but if you did the magazines wouldn’t have survived anyway.

Now, to start packing our books …

2023-12-04
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
Bobbin Rock: Bigger and Tighter

While loading bobbins for her next quilt project, Mary found another one that just wouldn’t fit on the winder:

Bobbin with polishing rock

Knocking the rock out of the bore required a pin punch and more than a gentle tap, but it eventually left without damage. The little stick in the slot looked organic, although it vanished without a trace during the operation.

I originally thought the bobbin factory’s final vibratory polisher used walnut shells, but the evidence certainly suggests ordinary gravel!

2023-11-27
Kitchen Sink O-ring Seat Polishers

My long-running battle with the American Standard kitchen sink O-rings continues, but this time I tried polishing the seats with a strip of 3M 2000 grit sandpaper:

Sink O-ring seat polisher – overview

Although it’s technically sandpaper, the effect is more like lapping than sanding and the O-rings now ride on a very smooth surface.

The knurled half-ring is ¼-inch = 6.3 mm acrylic with an ID precisely fitting the pillar + sandpaper:

Sink O-ring seat polishers

The one on the right has an OD matching the surface inside the spout, but it turned out to be easier using fingertips, even if that isn’t quite how one should do lapping.

The LightBurn layout shows the “knurls” are half-circles either added or subtracted from the arcs, as LightBurn’s Circular Array tool is my copilot:

O-ring Polishers – LB layout

You’ll want to measure the ID and OD of your sink faucet, as well as the thickness of your sandpaper, before making make your own.

Imagining / laying out / building those took less time than writing this up; I loves me some quick laser cutter action.

2023-11-24