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

Layered Paper: Inkjet Printer Skew
The Summer 2026 issue of Living Bird from the Cornell Bird Lab had a downloadable set of paint-by-number images that seemed tailor-made for laser-cut layered paper, so I laid out a test piece with targets in the corners:

Page 5 – Printed page test piece

Print that on fancy paper, drop it into the Letter cutting fixture, align the printed targets with the layout using the same technique as with the punched cards:
- Position the laser head at the center of a target in the LightBurn workspace
- Skootch the fixture to put the corresponding printed target under the red dot pointer
- Position the laser head at another target
- Skootch the other printed target to match
- Iterate until both align properly
I find that’s faster / easier / no less accurate than Print and Cut.

Then Fire The Laser:

Page 5 – Test piece – cutting

That’s cut over honeycomb, rather than empty space, because there’s not much paper left when the cutting is done and the remaining pieces distort the lacework:

Page 5 – Test piece – as cut

That layer (with binary code 0001) goes under the top black mask hiding the remaining colors on the lacework. The wing feathers and details seemed too small for slots cut into paper, so printing them finessed the issue.

I had aligned the fixture at the upper-right target:

Page 5 – Printed page test piece – cut top-right

And the lower-left target:

Page 5 – Printed page test piece – cut bottom-left

The printed lines are about 0.3 mm wide, so the cut alignment is off by that much in both X and Y.

The lower-right target is spot on:

Page 5 – Printed page test piece – cut bottom-right

But the upper-left target is off by nearly a millimeter in Y:

Page 5 – Printed page test piece – cut top-left

As well as I can measure, the printed image is slightly distorted, perhaps by the printer’s feed rollers skewing the paper slightly on its way through the printer. The laser-cut holes are, again as well as I can measure, dead on.

The punched card process required scaling the composited PNG image by 97%×97.9% so the image matched the laser-evaporated holes. This distortion seems different, but different paper and printer settings surely affect the outcome.

On the whole, though, the first test piece came out OK:

Page 5 – Test piece – stack oblique view

Those chonky feet need some attention.

Maybe three out of four ain’t bad …
2026-08-20
Kitchen Cupboard Tray Liners

Somewhat absorbent chipboard liners for the small trays / dishes under all the kitchen supplies in daily use:

Cupboard tray liners – installed

The tray bottom matched the flat surface of the top closely enough to let me lay a curve around the perimeter, with some attention to symmetry:

Cupboard Tray – LightBurn curve fit

Then Fire The Laser and it’s done!

For applications where actual symmetry matters, you’d want to lay a quarter of the curve and duplicate it across the midlines. In this case, however, an eyeballometric fit was entirely Close Enough™.

That was easy …

2026-08-18
Mini-lathe Cross Slide and Compound Backlash Tweakage
It being once again time to tweak the mini-lathe’s cross slide and compound backlash …

The M3 slotted setscrew locking the cross slide’s DRO collar to the feed screw shaft had come loose:

Mini-lathe – DRO slotted setscrew

Although it has a cone point, presumably to center the slot in the feed screw, an M3 cup point hex setscrew works just fine:

Mini-lathe – DRO hex setscrew

A hex socket is much easier to tighten securely.

The handle sits against a black washer that looks like it should rest against the aluminum spacer covering the DRO shaft, but it doesn’t. Contrary to what I originally thought, that gap doesn’t contribute to the backlash (given a tight setscrew!), but a filler shim makes it look less like an afterthought:

Mini-lathe – cross slide handle shim

What does contribute to the backlash is a loose adjusting screw holding the follower nut against the feed screw:

Mini-lathe – cross slide backlash screws

The mini-lathe manual (page 17) and online references give the tedious process required to adjust the two cap screws and the setscrew to remove (nearly all of) the backlash. While I had the screws out, I took the opportunity to dribble oil through the cap screw holes onto the feed screw along as much of its length as was reachable.

Adjusting the gib screws is also a good idea, as is renewing the oil along the ways.

With all that done, the cross slide moves easily without slop and the backlash is a tolerable 0.1 mm.

The compound feed screw does not have any backlash adjustment, so fitting a suitable shim between the handle and the DRO spacer is essential:

Mini-lathe – compound handle shim

That one looked nice, but was somewhat too thick.

This time around I could laser-cut and 3D print shims (16 mm OD, 10 mm ID) in a variety of thicknesses, some combination of which would surely fill the gap without binding:

Mini-lathe – handle backlash shims

The gnarly clear rings over on the left are the original punched-and-trimmed PETG shims. The fabric-looking ones are PTFE sheets intended for heat-press transfer machines, which Mary has used as a slider sheet to let fabric move easily over her sewing machines. The black one in the middle is 1.5 mm acrylic.

The bright white rings are 3D printed from a few lines of OpenSCAD code:
```
Washers = [0.5,0.6,0.7,0.8,1.2];

for (i = [0:len(Washers)-1])
  right(i*20.0 - 40.0)
    tube(Washers[i],od=16.0,id=(10.0 + HoleWindage),anchor=BOTTOM);
```
Print them with 0.1 mm layers in PETG, add a PTFE shim or two, and fiddle about enough to get minimum backlash with reasonable turning force.

The compound feed screw now has 0.16 mm of backlash, which is as good as it’s going to get.

Right now, the only thing preventing the handle from turning on the shaft is the chunky lockwasher gouging both the handle and the cap screw in the end of the shaft, with the side effect of putting far too much pressure on the spacer shims. I want setscrews in the handles bearing on flats filed in the feed screw shafts to put those awful screws + lockwashers out of business, which seems like a good Sherline project.
2026-08-13
Layered Paper 8×10 inch Gluing Fixture

An embiggened version of the 8×8 inch fixture, built with MDF for improved durability & flatness:

Layered Paper 8×10in Gluing Fixture – block

That’s an 8×8 quilt pattern as a quick fit check. Should I cut more of those, I’d install rivnuts in the obvious locations:

Layered Paper 8×10in Gluing Fixture – front overview

The white layer is 1 mm thick chipboard with the rivnut heads flush at its surface:

Layered Paper 8×10in Gluing Fixture – front detail

The perspective makes the fit look much worse than it is.

The back side has squishy foam feet keeping the M3 screws off the table:

Layered Paper 8×10in Gluing Fixture – back detail

The large rectangle on the LightBurn tool layer helped align the 8×12 inch MDF stock. The smaller squares show where the 8×8 inch square will fit and confirmed the hole locations:

Gluing Fixture – 200×200-250mm – LightBurn layout

The LightBurn SVG layout is a GitHub Gist, which also includes the template layout for cutting Letter pages to fit the fixture.

2026-08-12
Home Master CFKDF85GCC-20BB Water Filter Centering Blocks

The Home Master whole-house water filter setup that Came With The House™ has a sediment filter with a 6 to 12 months lifetime and a “catalytic carbon” filter that need replacing every 95000 gallons. Poughkeepsie City water isn’t particularly challenging and our average use suggests a three-year cycle for the carbon filter, so changing them every 18 months seems reasonable.

The filter headers have fingers to center the cartridges, which works well with the relentlessly cylindrical sediment filter. The header’s outlet orifice produces the indented ring around the central hole:

Sediment water filter – outlet

The water flows downward around the outside of the filter and upward through the central hole.

The carbon filter is about the same diameter, but has a smaller diameter around the outlet that apparently doesn’t engage the centering fingers:

Carbon water filter – off-center outlet

The white crud on the black rubber seal is another example of Nisley’s First Rule of Potable Water Plumbing:

Never ever look inside the pipes supplying your drinking water.

Having seen this happen twice, despite my best efforts to keep the filter housing vertical while tightening its screw threads in the header, I laser-cut four acrylic blocks to hold the filter in the center of the housing:

Carbon water filter – centering blocks

They’re 13 mm wide, 15 mm tall, and 6 mm thick, but the next time around they should be taller to help keep them vertical while sliding them into place.

We’ll know how well they worked in about 18 months.

2026-08-11
Quilting Ruler: Dual Semicircles

Along the same lines as the 45° triangle quilting ruler and the small arc quilting ruler, this one has a nonstandard 6-¼ inch diameter semicircle for the pattern Mary designed for a friend’s quilt:

Semicircular Ruler – on quilt

The 4-½ inch diameter semicircle is there because the larger half needed a handle for easier maneuvering. As with workshop clamps, quilters can never have enough rulers, so that curve will come in handy for something.

Unfortunately, I did not mirror-image the layout like this:

Semicircular Ruler – LightBurn layout

Which would make it correct when seen through the acrylic:

Semicircular Ruler – engraving

Given the very specific use case, I begged forgiveness and was not compelled to get it right.

The LightBurn SVG layout is a GitHub Gist.

2026-08-06
Laser-cut Window Screen

Having just cleaned a bunch of gunk out of the bottom of the worm bin, we decided to try a layer of window screen to keep both gunk and worms out of the sump.

A roll of window screen Came With The House™, minus label or provenance, that felt like some sort of plastic, perhaps with a glass core.

The bin has a 19-¼ inch = 488 mm ID with 10 thin support struts around the perimeter. Laying out a circle and cutting it accurately by hand seemed like a chore, even though the screen cut easily with ordinary scissors.

The diameter just barely fit on the laser’s 700×500 mm platform, so I laid it out in LightBurn:

Laser-cut window screen – LightBurn layout

For lack of anything smarter, I applied the same setting as for the faucet gasket material (30 mm/s at 25% of 60 W) and Fired The Laser.

As far as I could tell while the laser was trundling around the circle, absolutely nothing happened other than maybe burning off a coating with a little discoloration on either side of the path.

However, the circle lifted out with zero drama:

Laser-cut window screen

And was a perfect fit in the worm bin.

Color me surprised!

I have no pictures of the happy results, as all this happened in the few minutes between “We should try a screen”, dropping the cut screen in place, and reassembling the bin.

I think the screen would cut just as well with a higher speed. If the screen works and we need another, I’ll run a few tests first.

2026-07-17