Category: Machine Shop

Mechanical widgetry

Tour Easy: Broken Seat Parts

So hardened socket head cap screws survive fifteen years of hard service on my Tour Easy’s seat stay:

Tour Easy – broken seat stay screw

I replaced both screws with stainless steel 1-½ 10-32 socket head screws, with a reshaped head on the drive side, and we’ll see how long these last.

A few days later the continuing creak led to finding a broken gear clamp on the left side of the seat back:

Tour Easy – replacement seat frame clamp

Apart from the atypical lack of grime, you couldn’t tell that’s the replacement clamp, because the broken one looked exactly the same way. The clamp strap broke where it bent around the bottom edge of the seat pan bracket, probably due to the flexing caused by the broken seat stay screw.

Riding season is in full effect!

2025-04-24
Bird Box: Rotating T-Nuts

A bird box from long ago emerged from the heap and took its place in an upstairs window:

Bird Box window mount – installed

That big open back held an acrylic sheet letting us watch wrens raise their family; snugging it against the window makes that sheet superfluous. We’re hoping to lure the Wreath Finches from their preferred spot by the front door, but we’re open to any birds in need of a nesting spot.

The aluminum angle formerly securing the box to various wood window frames wasn’t going to work here, so I conjured a pair of rotating T-nuts to fit the track in the plastic window frame:

Bird Box window mount – nuts

They’re made from a 5/16-18 T-nut and two layers of 3 mm plywood, all glommed together with E6000-Plus adhesive because it did not scamper out of the way when I opened the Adhesives Cabinet.

Some doodling convinced me a pair of quarter-circles welded back-to-back, minus cutouts for the metal T-nuts, would suffice:

Bird Box window mount – nuts

The radius must be a little less than the width of the opening into the channel (20 mm) and the diameter must be a little more than the width of the channel behind that opening (32-ish mm), so I picked 17 mm. The metal T-nut flange is just over 20 mm, but the spike cutouts (omitted from the LightBurn layout) let it slip through the opening.

A random block of wood positions the box away from the frame enough to clear the outermost flange carrying the screen. Drilling oversize ⅜ inch holes countersunk the top of the T-nut into the block and eliminated excessive alignment fussiness.

Slicing 20 mm off the bolts fit them into the space available, with a pair of stainless washers covering the gaps.

A doodle with measurements you won’t need, but surely handy for mounting something else around here:

Bird Box window mount – size doodles

Now, to see who takes up residence …

2025-04-23
Champion Hose Nozzle: Needs a Washer?
An email discussion suggested the Champion hose nozzle might, once upon a time, have had a washer between the conical and cylindrical sections.

So I made one:

Champion hose nozzle – rubber washer

The details:
- OD = ½ inch
- ID = 9/32 inch
- 2.5 mm stamp pad rubber
It sealed perfectly, but, just before shutting off, the washer vibrated in the water flow and gave off an ear-shattering (even to my deflicted hearing) howl.

Perhaps a stiffer and thinner washer with a slightly larger OD would work better.

A quick check of similar nozzles in the Box o’ Hydraulics shows none of them feel like they have a compliant washer in there, but any sufficiently old rubber will have long since fossilized.

This seems like a good job for a 3D printed washer with a conical face, made from slightly squishy TPU plastic to ease it past the nozzle’s internal threads. All I need is the ability to print TPU …
2025-04-22
HQ Sixteen: Handlebar Control Button Labels

The recessed faceplate on the new handlebar control caps for Mary’s HQ Sixteen puts the label flush with the rim:

Control Button Caps – solid model – show view assembled

The current version of the labels isn’t much to look at:

HQ Sixteen control caps – new caps

The OpenSCAD code produces an SVG outline of the faceplate, surrounded by four alignment targets:

Control Button Caps – face view

Import the SVG into Inkscape and tart it up:

Control Button Caps – Inkscape

The alert reader will note the labels are swapped left-for-right.

The black characters on the left get printed on heavy white paper and laminated; feel free to add artistic embellishments. You must delete the cyan-ish shapes showing the faceplate and switch openings, which just show where the characters will end up, but you must print the four corner targets for alignment.

The red and orange shapes on the right define the outlines for laser-cutting the laminated paper and adhesive sheet after you import the Inkscape SVG file into LightBurn. The Inkscape colors will automagically put the shapes on separate LightBurn layers, with the cyan-ish shapes going onto non-cutting Tool Layer T2.

Set the cutting speed & feed to match your machine, lay the laminated labels on the platform, use Print and Cut to align two diagonal corner targets with the corresponding printed targets, then Fire. The. Laser.

The orange shapes have half a millimeter inset to leave a slight non-sticky margin around the edges:

HQ Sixteen control caps – adhesive layer

Although those shapes have the same four targets, you align the adhesive by hand and eye. Cut them out, peel one side, stick adhesive to the label, peel the other side, stick adhesive to the faceplate, and you’re done.

Now, to figure out the switch wiring …

2025-04-21

HQ Sixteen: Handlebar Control Button Caps

Each of the HQ Sixteen’s handlebars has a cap with control buttons:

HQ Sixteen control caps - side view — HQ Sixteen control caps – side view

The left cap:

HQ Sixteen control caps - left — HQ Sixteen control caps – left

The right cap:

HQ Sixteen control caps - OEM right — HQ Sixteen control caps – OEM right

The membrane switch overlay has textured bumps, although both of us have trouble finding them.

The Start / Stop switch gets the most use and, as you’d expect, has become intermittent after two decades of use.

Mary thinks a Start / Stop switch on both caps would be an improvement, letting her position quilting rulers with her right hand and run the machine with her left hand & thumb. I don’t know how the switches are wired, but the wiring suggests either simple single-bit inputs or a small matrix.

She also finds membrane switches difficult to press, so I’m in the process of replacing the control caps with something more to her liking.

The current concept goes a little something like this:

HQ Sixteen control caps - new caps — HQ Sixteen control caps – new caps

Stipulated: my art hand is weak.

Those are little bitty SMD switches:

HQ Sixteen control caps - new caps overview — HQ Sixteen control caps – new caps overview

They’re easy to locate by touch, with a stem length chosen to “feel right” when pushed.

They have been grievously misapplied:

HQ Sixteen control caps - switches — HQ Sixteen control caps – switches

The solid model has three main pieces and a lock for the ribbon cable:

Control Button Caps - solid model - build view — Control Button Caps – solid model – build view

Those pockets keep the switches oriented while the glue cures.

Two screws through the handlebar secure each cap. Handi-Quilter drove sheet metal screws into their OEM caps, distorting them enough to jam solidly into the handlebars. I’ve been reluctant to apply enough force to loosen them, so they remain frozen in place until the current quilt is done.

The new plugs have recesses for M3 square nuts to make them easily removable. As with the handlebar angle adapters, I’ll glue the plugs into the caps.

A slightly exploded view shows how the pieces fit together:

Control Button Caps - solid model - show view gapped — Control Button Caps – solid model – show view gapped

The switch plate sits recessed into the cap to allow room for the label (about which, more later):

Control Button Caps - solid model - show view assembled — Control Button Caps – solid model – show view assembled

The OpenSCAD source code as a GitHub Gist:

	// Handiquilter HQ Sixteen handlebar control button caps
	// Ed Nisley – KE4ZNU
	// 2025-04-05

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build,Grip,Body,Face,FaceBack,Plug,CableLock]

	// Angle w.r.t. handlebar
	FaceAngle = 30; // [10:45]

	// Separation in Show display
	Gap = 5; // [0:20]

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 234;

	WallThick = 3.0;

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

	Grip = [19.7,22.4,15.0]; // (7/8)*INCH = 22.2 mm + roughness, LENGTH=OEM insertion depth
	GripRadius = Grip[OD]/2;

	FoamOD = 34.0; // handlebar foam
	FoamRadius = FoamOD/2;

	SwitchBody = [6.3,6.3,4.0]; // does not include SMD leads
	SwitchStemOD = 3.5 + 2*HoleWindage;
	SwitchOC = 10.0; // center-to-center switch spacing
	LabelThick = 0.5; // laminated overlay

	FaceRim = 2.0; // rim around faceplate
	FaceThick = 2.0; // … plate thickness
	FaceDepth = FaceThick + LabelThick; // inset allowing for faceplate label

	CapOD = 38.0; // overall cap diameter
	CapTrim = FoamRadius; // flat trim on front
	CapBase = 5.0; // bottom thickness
	Cap = [FoamOD – FaceRim,CapOD,CapBase + CapOD*tan(FaceAngle)];
	echo(Cap=Cap);

	TargetSize = 4.0; // laser alignment targets
	TargetsOC = [40.0,40.0];

	Cable = [10.0,2.0,WallThick]; // aperture for cable lock

	ScrewAngles = [-45,45]; // mounting screws
	Screw = [2.0,3.0,7.0]; // OEM = sheet metal screw
	ScrewOffset = 6.0; // from top of grip tube

	SquareNut = [3.0,5.5,2.3 + 0.4]; // M3 square nut OD = side, LENGTH + inset allowance
	NutInset = GripRadius – sqrt(pow(GripRadius,2) – pow(SquareNut[OD],2)/4);

	PlugOA = [(Grip[ID] – 2*WallThick),(Grip[ID] – 1.0),(CapBase + ScrewOffset + 10.0)];
	echo(PlugOA=PlugOA);

	//———-
	// Define objects

	//—–
	// Handlebar tube

	module GripTube() {

	difference() {
	tube(3*Grip[LENGTH],GripRadius,Grip[ID]/2,anchor=TOP);
	for (a = ScrewAngles) {
	down(ScrewOffset) zrot(a-90)
	right(GripRadius)
	yrot(90) cylinder(d=Screw[OD],h=Screw[LENGTH],center=true,$fn=6);

	}
	}
	}

	//—–
	// SVG outline of faceplate for laser cuttery

	module FaceShape(Holes=true,Targets=false) {

	difference() {

	scale([1,1/cos(FaceAngle)])
	difference() {
	circle(d=(Cap[OD] – 2*FaceRim),$fn=144);
	fwd(CapTrim – FaceRim)
	square(Cap[OD],anchor=BACK);
	}

	if (Holes)
	for (i=[-1:1]) // arrange switch stem holes
	right(i*SwitchOC)
	zrot(180/8) circle(d=SwitchStemOD,$fn=32);

	}

	if (Targets)
	for (i = [-1,1], j = [-1,1])
	translate([iTargetsOC.x/2,jTargetsOC.y/2])
	square(2.0,center=true);
	}

	//—–
	// Faceplate backing sheet
	// Switch bodies indented into bottom, so flip to build

	module FacePlate(Thick=FaceThick,Holes=true) {

	difference() {
	linear_extrude(height=Thick,convexity=5)
	FaceShape(Holes);
	up(SwitchBody.z/4)
	for (i = [-1:1])
	right(i*SwitchOC)
	cube(SwitchBody,anchor=TOP);
	}
	}


	//—–
	// Cap body

	module CapBody() {

	$fn=48;

	up(CapBase + (Cap[OD]/2)*tan(FaceAngle)) xrot(FaceAngle)
	difference() {
	xrot(-FaceAngle)
	down(CapBase + (Cap[OD]/2)*tan(FaceAngle))
	difference() {
	cylinder(d=Cap[OD],h=Cap[LENGTH]);
	fwd(CapTrim) down(Protrusion)
	cube(2*Cap[LENGTH],anchor=BACK+BOTTOM);
	up(CapBase)
	difference() {
	cylinder(d=Cap[ID],h=Cap[LENGTH]);
	fwd(CapTrim – 2*FaceRim)
	cube(2*Cap[LENGTH],anchor=BACK+BOTTOM);
	}
	down(Protrusion)
	cylinder(d=Grip[ID],h=Cap[LENGTH]);
	}
	cube(2*Cap[OD],anchor=BOTTOM);
	down(FaceDepth)
	FacePlate(FaceDepth + Protrusion,Holes=false);
	}

	}

	//—–
	// Plug going into grip handlebar

	module CapPlug() {

	$fn=48;

	difference() {
	tube(PlugOA[LENGTH],id=PlugOA[ID],od=PlugOA[OD],anchor=BOTTOM)
	position(TOP)
	tube(CapBase,id=PlugOA[ID],od=Grip[ID],anchor=TOP);
	for (a = ScrewAngles)
	up(PlugOA.z – CapBase – ScrewOffset) zrot(a-90)
	right(PlugOA[ID]/2)
	yrot(90) {
	cube([SquareNut[OD],SquareNut[OD],SquareNut[LENGTH] + NutInset],center=true);
	zrot(180/6)
	cylinder(d=(SquareNut[ID] + 2*HoleWindage),h=PlugOA[ID],center=true,$fn=6);
	}
	}

	}

	//—–
	// Lock plate for ribbon cable

	module CableLock() {

	difference() {
	cuboid([2*Cable.x,PlugOA[ID],WallThick],rounding=WallThick/2,anchor=BOTTOM);
	for (j = [-1,1])
	back(j*Cable.y) down(Protrusion)
	cube(Cable + [0,0,2*Protrusion],anchor=BOTTOM);
	}

	}

	//———-
	// Build things

	if (Layout == "Grip") {
	color("Silver",0.5)
	GripTube();
	}

	if (Layout == "Face")
	FaceShape(Targets=true);

	if (Layout == "FaceBack")
	FacePlate();

	if (Layout == "Body")
	CapBody();

	if (Layout == "Plug")
	CapPlug();

	if (Layout == "CableLock")
	CableLock();

	if (Layout == "Show") {

	color("Green")
	up(CapBase)
	CableLock();

	color("Orange")
	down(Gap)
	down(PlugOA[LENGTH] – CapBase)
	CapPlug();

	color("Cyan",(Gap > 4)? 1.0 : 0.2)
	CapBody();

	color("White",(Gap > 4)? 1.0 : 0.5)
	up(Gapcos(FaceAngle)) fwd(Gapsin(FaceAngle))
	up(CapBase + (Cap[OD]/2)*tan(FaceAngle) – FaceDepth)
	back(FaceDepth*sin(FaceAngle)) xrot(FaceAngle)
	FacePlate();

	down(3*Gap) {
	color("Silver",0.5)
	GripTube();

	down(Gap)
	color("Gray",0.5)
	tube(3*Grip[LENGTH],FoamRadius,Grip[OD]/2,anchor=TOP);
	}
	}

	if (Layout == "Build") {
	right((Gap + Cap[OD])/2)
	CapBody();
	left((Gap + Cap[OD])/2)
	zrot(180) up(FaceThick) xrot(180)
	FacePlate();
	fwd(Gap + Cap[OD])
	up(PlugOA[LENGTH]) xrot(180) zrot(180)
	CapPlug();
	fwd(Cap[OD]/2)
	zrot(90)
	CableLock();
	}

view raw Control Button Caps.scad hosted with ❤ by GitHub

2025-04-18

HQ Sixteen: Bobbin Winder Split Shaft Tweak
The HQ Sixteen has much larger bobbins than Mary’s Kenmore and Juki sewing machines. It also came with a dedicated bobbin winder:

HQ Sixteen bobbin winder – overview

That thing has a distinct Industrial Revolution aspect compared to the BarbieCore bobbin winder I laid hands on a while ago.

Out of the photo on the right:
- The thread cone and guide tower
- The thread tension disks
Mary had been having trouble winding the bobbins, as the tension seemed entirely too low and the thread did not lay smoothly across the bobbin, so she asked me to take a look.

The motor shaft has an O-ring for friction drive against the large wheel driving the shaft with the bobbin on the other end. The small silver lever over on the left flips an over-center lock pressing the wheel against the O-ring and tripping the microswitch in the aluminum housing, thus turning the motor on. The bobbin fills until a small finger monitoring the thread level flips the lock back over center, the wheel disengages, the switch turns the motor off, and a spring drives the wheel against the rubber rod in the upper left.

Which worked well, but all the bobbins had a loose-to-sloppy fit on the shaft, to the extent that the shaft really couldn’t drive them against any thread tension.

Loosening the screw holding the drive wheel on the shaft lets it slip off and the shaft slides out to the front:

HQ Sixteen bobbin winder – split shaft

The sides of the split shaft should press firmly against the bobbin core, but that just wasn’t happening.

Measuring a dozen bobbins showed most had an ID of 6.04 mm, with a few around 6.01 mm; unsurprisingly, the latter had the best, albeit still loose, fit. Conversely, the split shaft had two isolated points 6.01 mm apart across a diameter, with the remainder around 5.95 mm. Those are not large differences, but it was obvious why the bobbins didn’t wind correctly.

I filed some graunch off the split edges, then gently pushed the Designated Prydriver into the end of the split to spread the sides juuuust a little bit, until all the bobbins pushed on firmly and fit snugly:

HQ Sixteen bobbin winder – split shaft test fit

It reassembled in reverse order and we’ll see how it behaves during the next marathon bobbin-filling session.
2025-04-15
Champion Hose Nozzle: Refreshed Seal Attempt

The battered Champion hose nozzle came into play last fall, leaked profusely when turned off, went to a Safe Place for the winter, and recently emerged:

Champion hose nozzle – disassembled

The conical surface (to the right of the tip) must make perfect contact with the edge of a perfect cylindrical hole in the outer shell to shut off the water, which was obviously no longer happening.

There is no reason why that hole should still be concentric with the outside of the shell, but centering the latter in the four-jaw chuck put the hole within about 0.2 mm of where it should be:

Champion hose nozzle – lathe centering

I defined that to be Close Enough™ and made the hole smooth & concentric with a teeny boring bar and sissy cuts. A drill would likely have worked well enough, too.

Gently filing the nastiness off the cone showed it wouldn’t suffice, so center it while noting the irregular diameter all around:

Champion hose nozzle – lathe centering cone

A skim cut revealed the need for more attention:

Champion hose nozzle – scarred cone

Another tenth of a millimeter improved its disposition:

Champion hose nozzle – improved cone

Gentle touchup with a fine file reserved for special occasions may have been a further improvement:

Champion hose nozzle – finish filed

Add a dollop of silicone grease to encourage the shell to turn much more easily on the O-ring, reassemble in reverse order, and top it off with a new hose washer.

A quick test on a reasonably warm day showed the cone met the cylinder poorly enough to consign this nozzle to the brass recycling box.

It was fun trying, though …

2025-04-14