Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
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.
Although it may not be obvious from the picture, unlike my cardboard insert, the acrylic insert does not fill the tabletop hole to the immediate right of the machine:
Custom Inserts are U-shaped, designed to fit around all 3 sides of your sewing machine
Shortly after the insert arrived I hacked a temporary filler, for which no pictures survive, to keep pins / tools / whatever from falling to their doom. This turned out to be a blessing in disguise, because she wanted the machine positioned an inch to the right of its intended spot to leave enough space for a finger to reach the bobbin hatch latch.
I then promised to replace the ugly cardboard filler with a less awful acrylic filler and finally got it done:
Juki TL-2000Q in Gidget II table – insert filler
The stack of cardboard prototypes show iterative fit-and-finish improvements, with the odd shape on the top serving to measure the machine’s 25 mm corner radius by comparison with known circles.
The insert filler is made from smoked gray acrylic, because I have yet to unpack the acrylic stockpile and may not, in fact, have any clear 6 mm acrylic, so we’ll regard this as a final prototype pending further developments. It did, however, confirm the laser survived the move, which was pretty much the whole point.
The end of the machine is not a straight line. Part of the iteration was measuring the curve’s chord height to calculate the circle’s radius, which turned out to be 760 mm:
Juki Insert Filler – end chord circle
With that in hand, a few Boolean operations produced the filler shape:
Juki Insert Filler
A pair of silicone bumper feet stuck to the side of the Juki hold the left edge of the filler at the proper level.
For the record, the smoked acrylic came from a fragment of a Genuine IBM Printer stand I’ve had in the scrap pile since The Good Old Days:
Our ancient Kenmore microwave has a three-armed turntable drive:
Kenmore Microwave – turntable installed
After all these years the (white) rollers have worn to the extent they fall off the (brown) drive arms all too easily. They ride in a recessed track in the glass plate that holds them in place during normal operation, but having once again found a roller wandering around when I put the turntable back in, it’s time for at least a temporary fix.
Everything is, of course, plastic:
Kenmore Microwave – turntable drive roller parts
I considered drilling the end of the axle and tapping it for a nylon screw + washer, but came to my senses just in time:
Kenmore Microwave – turntable drive
The laser-cut parchment paper disk (barely) fits over the axle against the outside of the roller, while allowing the hot-melt glue to glom onto the undercut and hold everything in place:
Kenmore Microwave – roller glopped
I expect the paper to wear / fall off in short order, but the HDPE roller won’t bind against the glue and the blob should remain latched in place for a while.
When those hideous glue blobs do fall off, I’ll reconsider drilling & tapping. More likely, I’ll just fire up the glue gun again.
Actual use required trimming the blob from the upper side of the roller / hub, because the track in the glass plate fits very close against the edge of the roller. The hideous glue blob slid freely on the roller, but jammed firmly against the plate, causing it to turn at half speed.
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.
A couple of test shots to verify the move hasn’t jostled the laser mirrors too far out of alignment:
Laser cutter alignment check
The overlapping scorches on the left happened at the Mirror 3 position with the laser head at the far left and near right positions. Not quite as accurate as immediately after I overhauled the beamline, but close enough.
The pair of dot + disk scorches on the right show the beam position on the platform at the focus point and 20 mm below. The red-dot pointer definitely traces a wavering path as the platform goes down, suggesting the leadscrews may have taken a sideways jolt during the laser’s trip down the basement stairs and are now distinctly angled in their guides, but it’s good enough for my simple needs.
Looks like the laser survived the move pretty much intact!
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.
The Smell of Molten Projects in the Morning 
