Tag: Improvements

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

OXO Pepper Mill: Fine Grind Adjustment
The OXO pepper mill replacing our worn-out pepper mill arrived filled with peppercorns and, during the ensuing nine months, we established its finest grind setting produced bigger pepper flakes than we prefer. I figured there had to be a way to get the ceramic stones just a little bit closer, even though it has no user-serviceable components inside.

So, we begin.

After rinsing out most of the pepper flakes (the remainder appearing in the pictures below) and determining the two obvious screws didn’t release the housing, the Jesus clip on the shaft extending through the peppercorn compartment came under consideration:

OXO Pepper Mill – E-clip on shaft

The washer beyond the clip bears on the black plastic spider. It turns out the thickness of that washer determines the distance between the grind stones at the minimum setting: making it thicker reduces the stone gap and produces a finer grind.

Knowing full well it would be impossible to get the clip back on the shaft in that position, I pried it off.

Spoiler: Don’t do that!

The grind adjustment lever turns the chunky black ring inside the gray housing:

OXO Pepper Mill – grind adjustment rings

Three protrusions on that ring step along notched ramps around the perimeter of the black spider in the clear housing on the right.

The shaft slides out to reveal the spring under the inner stone, with a second washer bearing against the bore of the gray plastic housing:

OXO Pepper Mill – upper shaft parts layout

As a result, the spring tries to push the shaft and inner stone out of the housing (toward the left). The protrusions on the grind adjustment control how far the shaft can move, with the washer + clip locking the shaft to the spider.

Gentle persuasion extracts the chunky black ring:

OXO Pepper Mill – grind adjust slider

The outer stone fits into a recess in the gray housing:

OXO Pepper Mill – outer stone

One might 3D print a washer fitting under that stone to close the gap between it and the inner stone, but the two screw holes interrupt the ledge enough to suggest the washer would be in two parts divided. If I didn’t have a mini-lathe, that’d be the best way to go.

But I have a mini-lathe, so I made a steel washer slightly thicker than the OEM washer under the clip:

OXO Pepper Mill – turning new washer

The OEM washer:
- ID 6.7 mm
- OD 10.2 mm
- Thick 0.6 mm
Not knowing the right answer, I made a 1 mm washer, which is visibly thicker:

OXO Pepper Mill – 1mm vs OEM washer

Which let me reassemble the pepper mill in reverse order, only to establish reinstalling the Jesus clip deep down inside the housing is, in fact, impossible.

Taking everything apart again let me contemplate the inner stone on the shaft, leading to the discovery it could slide very slightly on the shaft. More pondering revealed a slight seam in what I had taken as a monolithic black cap:

OXO Pepper Mill – inner stone assembled

Applying gentle suasion between the stone and the cap with a plastic razor blade enlarged the seam into a gap. Much to my surprise, further prying popped the top off the cap:

OXO Pepper Mill – inner stone cap

Happy dance in full effect!

Removing the screw let everything slide off the top of the shaft:

OXO Pepper Mill – inner stone parts

Freeing that end of the shaft meant I could install the clip on the bench, add various parts while sliding the shaft through the housing, then tighten the screw to snug everything down.

As with most activities, it’s trivially easy when you know the trick.

Whereupon I discovered the new 1 mm washer jammed the two stones firmly together at the finest grind setting, so the correct washer will be somewhere between 0.6 and 1.0 mm thick:
- Back to the lathe for a 0.8 mm thick washer
- Dismantle pepper mill
- Swap washers
- Reassemble
- Verify smooth turning at finest setting
- Fill with peppercorns
- Give it a twist
A shower of pepper flakes in a cup:

OXO Pepper Mill – finer grind

The mill undergoes a full qualification test tomorrow morning, but those flakes look much better.

Fun fact: the OXO pepper mill holds 2.0 oz of peppercorns, so we use 0.033 oz = 940 mg of pepper every day.
2026-03-06
Punched Cards: Paper Matters

Using different card colors makes it easy to find your program deck in the Comp Center’s output bins:

Punched Cards – paper color vs smoke stains

The smoke stains on the bottom orange card came from the same LightBurn settings used with the purple (violet?) and blue (teal?) cards: 400 mm/s, 35% power, and assist air enabled.

The conventional wisdom is that you *do not* use assist air while engraving, to avoid pushing the smoke / soot down onto the material, and I’ve generally followed that rule. Apparently evaporating holes in the other colors doesn’t generate much smoke and I had no reason to notice the air was enabled.

The upper orange card differs from the lower one only in having the assist air turned off, so I have definitely learned my lesson!

Readers of long memory will recall the dual-path assist air setup that pushes 2 l/m through the nozzle when the LightBurn layer has AIR disabled, specifically to keep smoke out of the nozzle and away from the lens; that gentle breeze doesn’t push smoke into the paper.

FWIW, that’s why I run a set of test cards before I do anything fancy for the first time.

2026-02-27

HQ Sixteen: Fabric Rod Bearings

The rods (a.k.a. tubes or poles) holding & guiding the quilt top / batting / backing fabric on Mary’s HQ Sixteen longarm quilting machine span the eleven feet of the table:

HQ Sixteen - table overview — HQ Sixteen – table overview

The two end plates are 1/4 inch steel plate with four punched holes for the rods / tubes, which look remarkably like EMT. The machine is two decades old and Mary is (at least) the third owner, so it’s no surprise the rods long ago wore through the white powder-coat paint on the plates and, during the course of a long quilting project, now deposit black dust on the table.

Black dust not being tolerable near a quilt-in-progress, Mary asked for an improvement.

The tube OD is 28.7 mm (so it’s probably 1 inch EMT) and the plate hole ID is 31.2 mm (likely a scant 1-¼ inch punch), leaving barely a millimeter of clearance all around. I wanted to make a bearing from suitably slippery Delrin / acetal, but figured 3D printed PETG would suffice for at least while.

The proper term is “bushing“, because it has no moving parts:

Rod Bearing Sleeve - solid model - show view — Rod Bearing Sleeve – solid model – show view

On the right side, the bushing rim must fit between the sprockets and the plate:

HQ Sixteen rod - right front — HQ Sixteen rod – right front

The spring-loaded pin holding the tube in place (visible on the inside bottom) sets the maximum length:

HQ Sixteen rod - right outer — HQ Sixteen rod – right outer

The left side has none of that, so I made the bushings a little longer:

HQ Sixteen rod - left inner — HQ Sixteen rod – left inner

The left-side bushings will need a better design should normal back-and-forth sliding push them out of place.

A touch of silicone grease around the plate holes makes those bushings / bearings turn sooo smooth.

The OpenSCAD source code as a GitHub Gist:

	// Bearing sleeve for HQ Sixteen table rods
	// Ed Nisley – KE4ZNU
	// 2026-02-20

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build]

	/* [Hidden] */

	ID = 0;
	OD = 1;
	LENGTH = 2;

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 832*4;

	$fn=NumSides;

	Rod = [25.0,28.7,100.0]; // very short rod

	Sleeve = [Rod[OD] + 0.3,31.2 – 0.2,9.0]; // LENGTH = overall
	Rim = [Sleeve[ID],Sleeve[OD] + 6.0,0.6];

	IdlerLength = 15.0;

	NumSlots = 2*4;
	Kerf = 1.0;

	Gap = 5.0;

	module Bearing(oal) {

	difference() {
	union() {
	tube(oal,id=Sleeve[ID],od=Sleeve[OD],anchor=BOTTOM);
	tube(Rim[LENGTH],id=Rim[ID],od=Rim[OD],anchor=BOTTOM);
	}
	for (a=[0:NumSlots-1])
	zrot(a*360/NumSlots)
	up(oal/4 + Rim[LENGTH])
	right(Sleeve[ID]/2)
	cuboid([Sleeve[OD],Kerf,oal],anchor=BOTTOM);
	}

	}


	//—–
	// Build things

	if (Layout == "Show") {
	color("Gray",0.5)
	xcyl(Rod[LENGTH],d=Rod[OD]);
	right(Rod[LENGTH]/3)
	yrot(90)
	Bearing(Sleeve[LENGTH]);
	left(Rod[LENGTH]/3)
	yrot(90)
	Bearing(IdlerLength);
	}

	if (Layout == "Build") {
	right(Rim[OD]/2 + Gap/2)
	Bearing(Sleeve[LENGTH]);
	left(Rim[OD]/2 + Gap/2)
	Bearing(IdlerLength);


	}

view raw Rod Bearing Sleeve.scad hosted with ❤ by GitHub

2026-02-23

Punched Cards: Layered Apollo Eagle
What with punching the Apollo 11 CSM source code into the cards, converting the mission’s eagle into a layered shape made some sense.

The original Apollo 11 mission patch:

Apollo 11 mission patch – rescaled

After considerable faffing, a few of the fifteen layers look like this in GIMP:

Apollo 11 Patch – eagle layers

Each layer is a connected white region defining the cut perimeter, which will expose some part of the layer(s) below it in the stack. The small squares in the corners provide a bounding box to make all the layers snap to the same location.

Then:
- Select each layer’s shape + corner boxes with GIMP’s Color Select tool
- Convert the selection to a path
- Export paths as SVG files (all fifteen of them!)
- Import SVGs into LightBurn & arrange neatly
- Put outlines on a cut layer, corner squares on a tool layer
- Burn each layer separately
Testing the concept with packing paper looked surprisingly good:

Apollo 11 Eagle – layer test piece

A few key layers on punched cards:

Apollo 11 Eagle – card partial test piece

The changes for each of those iterations required tweaking the original layer images to eliminate obvious-in-retrospect problems, recreating the SVG files, and importing into LightBurn. This is a relentlessly manual process.

Then I ran a full-up test of all fifteen layers on cards punched with the Apollo source code.

Cutting the head layers from face-down cards made them sufficiently white, although it’d be nice to have a different beak color and darker eyes :

Apollo 11 Eagle patch – layer test – head

I must arrange the cards with text to put more holes in the wings, although too many will cause fragile feathers:

Apollo 11 Eagle patch – layer test – wing

The white tail should be also done with face-down cards, more holes, and the three-way joint between the cards shifted under the tail layers to its left:

Apollo 11 Eagle patch – layer test – tail

The feet and olive branch were a total faceplant, as successive layers did not register accurately enough to overlay the leaves:

Apollo 11 Eagle patch – layer test – feet

Not to mention those ug-u-lee claws.

The wing layers need more rounding along their edges, perhaps with some thin cuts to emphasize the feathers.

On the whole, though, I think it turned out well.

Things to do:
- Registration holes / pins up to the top layer
- Remove speckles on all the layers
- Arrange cards for more hole density where needed
- Better glue application
- Different card colors?
2026-02-19
Work Sharp Precision Sharpener: Knob Lock

Having recently sharpened a small blade at a very low angle, I must put in a good word for the knob lock found on Printables:

WorkSharp – knob lock

The protrusion on the tab fits into the back side of the frame, but it works well enough in front, too.

Wearing cut-resistant gloves remain a good idea.

2026-02-18
Cheap HD USB Camera: Base Disassembly
A brace of cheap HD USB cameras may improve the scenery around here during video meetings. They were $16, marked down from an absurd $130:

HD USB Camera price history

Some poor schlubs certainly dropped more than twice the price of a Genuine Logitech camera on these critters, but a nearly total lack of demand must have had some effect.

They do take their stylin’ cues from Logitech, although the speckled pattern on a shiny plastic sheet is amusing:

HD USB Camera – styling vs Logitech C920

Unsurprisingly, the lens is fixed / manual focus. What looked like focus rings were in different positions on the two cameras:

HD USB Camera – lens focus notches

It turns out the rings were not glued in place, perhaps because they have absolutely no effect on the camera’s focus. Maybe there’s another camera model where they rotate the lens in a threaded socket, but this ain’t that.

The front panel has three pores:
- A red Power LED is always on when it’s plugged in
- A green On the air LED lights up when the camera is selected; I have no idea what the WiFi-ish glyph is supposed to represent
- The “advanced noise canceling microphone” sits behind a pore offscreen left; the claim seems dubious.
Because these may go into smaller spaces, I dismantled the base to see what was involved. Most of the screws lie underneath thin foam sheets:

HD USB Camera – ball mount interior

The lower plate has a tripod mount and a folding bracket:

HD USB Camera – baseplate interior

The camera body has a ball mount with a few degrees of movment:

HD USB Camera – ball mount detail

Reassembled and stuck inside the laser cabinet with some good double-sided foam tape, it definitely produces a better image than the previous camera:

Platform camera view

Whatever noise cancellation the mic may provide is irrelevant in there: nobody’s listening.
2026-02-17
OMTech Laser Cutter: Custom Air Fitting Wrench

Changing the lens on the laser requires unscrewing the nozzle after removing the assist air fitting that collides with the focus pen holder:

Laser head – assist air vs focus pen

All the 12 mm open-end wrenches in my Drawer o’ Spare Wrenches being much too large, I finally got around to making a custom wrench:

Air fitting wrenches

The plywood wrench came from a traced scan of a similar wrench, then adjusting the jaw opening to 12 mm. It served to verify the overall shape & size, then became a template for the real wrench atop a scrap of 1/8 inch aluminum sheet with flaking paint.

Some bandsawing and filing later:

Air fitting wrench – at nozzle

A little wrench makes swapping the lens somewhat less tedious, which is a Good Thing™.

Protip: Remember to adjust the Focus Distance by the difference between the two lenses.

2026-01-30