Laser-cut Pole Bean Ties

This is the season for erecting the structures upon which the pole beans will climb:

Garden Bean Poles - overview
Garden Bean Poles – overview

They’re made from a dozen small trees and branches of larger trees harvested around the yard. They last for a few years, just long enough for the next crop to reach useful lengths.

We lash them together with fabric strips:

Garden Bean Poles - joint detail
Garden Bean Poles – joint detail

My knot hand is weak, but seems sufficient to the task.

Mary formerly tore the strips from old jeans / pants / whatever, which required considerable effort, produced ragged edges, and filled the air with fabric dust. This year, I proposed an alternative:

Garden Bean Poles - laser cutting ties
Garden Bean Poles – laser cutting ties

The weird thing in the middle is a reflection of an overhead can light in the laser cabinet’s polycarb lid.

From starting the LightBurn layout to presenting the strips for final inspection required the better part of ten minutes. I scissors-cut along the main seams to get single fabric layers, with everything above the crotch seam wadded off the platform to the left.

As with my shop raglets, the layout depends on LightBurn’s overhead camera view to align the cuts with the fabric on the platform:

Bean Pole Ties - LightBurn layout
Bean Pole Ties – LightBurn layout

It’d be easier to see with lighter fabric, but that’s what came to hand in the scrap box and the beans won’t care. We do not anticipate complaints about the odor of charred fabric when they reach the top of the poles, either.

The strips must align with the fabric’s grain to put the warp threads along their length, which makes the main side seam parallel to the X-axis. Even I can handle that layout!

Yes, the strips have rounded corners and, no, it doesn’t matter.

OMTech 60 W Laser: Plant Markers

While calibrating the laser’s scan offset, I also tried various fonts:

Offset cal - text - overview
Offset cal – text – overview

Putting two lines of the most-readable font inside an outline reverse-engineered from a few handwritten samples let me cut out a bunch of plant markers from white-on-black Trolase acrylic:

Plant Markers - cutting
Plant Markers – cutting

Which look downright dignified in real life:

Plant markers - African Violet
Plant markers – African Violet

Admittedly, sweet potato slips don’t require such extensive documentation:

Plant Markers - sweet potatoes
Plant Markers – sweet potatoes

Cutting the sheet flat on the honeycomb platform worked well, modulo Sadler’s warning about cutting acrylic, and a few smudges on the back of the markers will go unnoticed.

This was actually an excuse to use LightBurn’s Variable Text feature, so the tags contain formatting codes:

Plant Markers - Variable Text template
Plant Markers – Variable Text template

The codes give the position and format for text fields in a CSV file containing one line for each tag:

Austrocylindropuntia subulata,Eve’s Pin Cactus
possibly G. Carinata,var. Verucosa
African Violet,Maui
Sansevieria trifasciata,Mother in law’s tongue
Plectranthus,'Mona Lavender'

The rules governing quoted strings and suchlike remain to be explored, but single quotes in the CSV file pass through unchanged.

Putting a tab at the point of the marker will prevent it from falling free when cut out, should you want to try raising the sheet above the platform to reduce the amount of crud accumulating on the back side.

Garden Cart Handle Pivot

For reasons not relevant here, I was tapped to replace the plastic parts attaching the handle to a garden cart:

Garden Cart - handle attachment
Garden Cart – handle attachment

The owner tried to contact the “manufacturer” to no avail; repair parts are simply not available, even if the name painted on the cart had a meaningful relationship to anything else.

Well, I can fix that:

Garden Cart - handle repair parts
Garden Cart – handle repair parts

Fortunately, another cart in the fleet provided the missing bits so I could reverse-engineer their measurements.

The solid model looks about like you’d expect:

Garden Cart Handle - show view
Garden Cart Handle – show view

Printing the two halves with those nice (yellow) bosses in place wasn’t feasible. They were exactly 1 inch in diameter, so I just parted two cookies from the end of a stout acetal rod after drilling a hole for the 2-¼ inch 5/16-18 bolt.

The two pieces took nigh onto three hours with five perimeters and 50% infill:

Garden Cart Handle - slicer preview
Garden Cart Handle – slicer preview

While delivering and installing the parts, I got volunteered to haul plants to cars with one of the carts during the upcoming Spring Plant Sale. That’ll teach me to stay in the Basement Shop …

The OpenSCAD source code as a GitHub Gist:

// Garden Cart Handle Pivot
// Ed Nisley KE4ZNU 2022-05
Layout = "Show"; // [Show,Build]
/* [Hidden] */
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleWindage = 0.2;
Protrusion = 0.1; // make holes end cleanly
inch = 25.4;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
ID = 0;
OD = 1;
// Dimensions
// Handle lies along X axis
HandleOD = (7/8) * inch;
BoltOD = (5/16) * inch;
Washer = [BoltOD,1.0 * inch,2.0]; // just for Show
Disk = [BoltOD,62.0,(3/16) * inch];
ClampBase = [(1 + 7/8)*inch,(1 + 1/8)*inch,2.0];
Kerf = 2.0;
CornerRadius = 1.0;
PivotOA = [Disk[OD],Disk[OD],HandleOD + 2*ClampBase.z + 2*Disk[LENGTH]];
// Useful routines
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(d=(FixDia + HoleWindage),h=Height,$fn=Sides);
// Set up parts
module Handle() {
module Bolt() {
module Pivot() {
difference() {
union() {
for (i=[-1,1], j=[-1,1]) // rounded block
translate([i*(ClampBase.x/2 - CornerRadius),j*(ClampBase.y/2 - CornerRadius),-PivotOA.z/2])
for (k=[-1,1])
translate([0,0,k*(PivotOA.z/2 - Disk[LENGTH]/2)])
cube([2*ClampBase.x,2*ClampBase.y,Kerf],center=true); // slice through center
// Build them
if (Layout == "Show") {
rotate([90,-45,0]) {
translate([2*PivotOA.x - PivotOA.x/2,0,0])
for (k=[-1,1])
translate([0,0,k*(PivotOA.z/2 + Washer[LENGTH])])
if (Layout == "Build") {
Offset = 5.0;
intersection() {
translate([-(PivotOA.x/2 + Offset),0,PivotOA.z/2])
intersection() {
translate([(PivotOA.x/2 + Offset),0,PivotOA.z/2])

Laser-cut Cutworm Collars

Mary, having had considerable trouble with cutworms in her gardens, routinely deploys cardboard collars around new plants:

Cutworm Collars - assembled
Cutworm Collars – assembled

It seems cutworms trundle around until they find an edible plant, chew through the stem and topple the plant, then trundle off without taking another bite. A small cardboard barrier prevents them from sensing the plant: apparently, motivation to climb a short wall hasn’t yet evolved.

Up to this point, Mary applied scissors to tissue boxes, but I proposed an alternative with an adjustable fit to any plant:

Laser Cutting Cutworm Collars
Laser Cutting Cutworm Collars

A splayed cardboard box rarely lays flat, a condition enforced by a few MDF stops used as clamps.

Come to find out no two tissue boxes have identical dimensions, even boxes from the same brand / retailer, so lay out duplicates of the collar template to match your stockpile.

That was fun!

The SVG image as a GitHub Gist:

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Euphorbia Horrida Flower

A Euphorbia horrida (one of the prickly plants) on the shelves just inside the front window burst into bloom:

Euphorbia Horrida - flowers
Euphorbia Horrida – flowers

The flowery part looks unappetizing, but some critter must find the blooms attractive:

Euphorbia Horrida - flower - side
Euphorbia Horrida – flower – side

The small reddish balls look like the desert equivalent of nectar, as they’re viscous to the point of solidity:

Euphorbia Horrida - flower resin - top
Euphorbia Horrida – flower resin – top

I’m unwilling to experiment, but the resin ought to very sweet, lethally toxic, or wildly hallucinogenic. Maybe all three at once?


We spotted a plump mushroom cluster nestled at the base of a neighbor’s tree:

Mushrooms at tree - A
Mushrooms at tree – A

Eight days later they’d started curling:

Mushrooms at tree - B
Mushrooms at tree – B

Mushrooms growing on tree roots generally mean the tree is in trouble and, indeed, it’s a battered Black Locust.

Sticky Trap Results

In late May we deployed six sticky traps in and around the onion bed, attempting to reduce the number of Onion Fly maggots. By mid-June the sheets were covered with the shredded leaves Mary uses to mulch the onions, but half a dozen flies were out of action:

Sticky trap - 2021-06
Sticky trap – 2021-06

We’re pretty sure that’s what these things are:

Sticky trap - Onion Fly - 2021-06
Sticky trap – Onion Fly – 2021-06

They’re supposed to have red eyes, but being affixed to a sheet of snot for a few weeks doesn’t do the least bit of good for your eyes.

We replaced the sheets and left them in place until the end of July:

Sticky trap - 2021-07
Sticky trap – 2021-07

The sheets took another half-dozen flies out of circulation, Mary began harvesting the onions, and observed it was the healthiest onion harvest she’s ever had.

We declared victory, removed the traps, and the remaining onions suffered considerable maggot damage over the next few weeks.

Anecdotally, it seems reducing the Onion Fly population by (what seems to be) a small amount and maintaining pressure on the population dramatically reduces the number of maggots available to damage the onion crop. At least for a single bed in a non-commercial setting.

The plural of anecdote is not anecdata, but we’ll try it again next year, leave the traps in place while the onions are in the ground, and see what happens.