Tag: Sewing

Fabric arts and machines

Electronics Workbench, Home Ec, Machine Shop

Juki JC-001 Foot Control: Resolving Uncommanded Thread Cutting

Mary’s most recent quilt arranges her color choices in Judy Niemeyer’s Stellar Snowflake pattern:

Stellar Snowflake Quilt - in progress
Stellar Snowflake Quilt – in progress

Her Juki TL-2010Q sewing machine has a built-in thread cutter activated by pressing down on the heel end (to the left) of the foot control:

Juki JC-001 Foot Control - overview
Juki JC-001 Foot Control – overview

The machine had previously performed “uncommanded” thread cuts on other projects, but the many short segments in this pattern triggered far too many cuts. I aimed a camera at her foot on the pedal and she was definitely not pressing down with her heel when the cutter fired.

In point of fact, the thread cutter fired when she was just starting a new segment, where she was gently pressing down on the toe end (to the right) of the pedal to start at the slowest possible speed.

For completeness, the underside of the pedal:

Juki JC-001 Foot Control - bottom
Juki JC-001 Foot Control – bottom

There are no screws holding it together. The top cover pivots on a pair of plastic pegs sticking out from the base near the middle of the cable spool. Disassembly requires jamming a pair of husky Prydrivers in there and applying enough brute force to pry both sides outward farther than you (well, I) think they should bend. This will scar the bottom of the case, but nobody will ever notice.

The foot control cable plugs into the machine through what looks like an ordinary two-conductor coax plug, just like the ones on wall warts delivering power to gadgets around the house. In this day and age, the communications protocol could be anything from a simple resistor to a full-frontal 1-Wire encrypted data exchange.

Based on the old Kenmore foot pedals, I expected a resistive control and, indeed, a simple test gave these results:

  • Idle = 140 kΩ
  • Heel pressed (cut) = 46 kΩ
  • Toe slight press (slow running) = 20 kΩ
  • Toe full press (fast running) = 0.2 kΩ

We can all see where this is going, but just to be sure I pried the top off the control to reveal the insides:

Juki JJC-001 Foot Control - interior
Juki JJC-001 Foot Control – interior

The two cylindrical features capture the ends of a pair of stiff compression springs pressing the top of the pedal upward.

The small, slightly stretched, extension spring in the middle pulls the slider to the left (heelward), with a ramp in the top cover forcing it to the right (toeward) as the speed increases.

The top cover includes a surprisingly large hunk of metal which may provide enough mass to make the pedal feel good:

Juki JC-001 Foot Control - top underside
Juki JC-001 Foot Control – top underside

The ramp is plastic and the slider has a pair of nylon (-ish) rollers, so there’s not much friction involved in the speed control part of motion. Yes, this is oriented the other way, with the heel end over on the right.

The metal insert pivots in the serrated plastic section near the middle, with the two husky extension springs visible on the left holding it against the plastic cover. The two rectangular features on the left rest under the plastic flanges on the right of the base to prevent the metal insert from moving upward, so pressing the heel end down pulls the cover away from the insert to let the slider rollers move toward the right end of the ramp, into roughly the position shown in the interior view.

A closeup look at the slider shows the rollers and the PCB holding all of the active ingredients:

Juki JC-001 Foot Control - Resistor Slider
Juki JC-001 Foot Control – Resistor Slider

I think the trimpot adjusts the starting resistance for the slider’s speed control travel. It is, comfortingly, roughly in the middle of its range.

A top view shows the fixed 140 kΩ resistor (brown yellow black orange, reading from the right) setting the idle resistance:

Juki JC-001 Foot Control - PCB top view
Juki JC-001 Foot Control – PCB top view

Measuring the resistance while gently teasing the slider showed that it’s possible to produce a resistance higher than 20 kΩ and lower than 140 kΩ, although it requires an exceedingly finicky touch and is completely unstable.

Before looking inside the pedal, we thought the cutter was triggered by an actual switch closure with the heel end most of the way downward against those stiff springs, which meant the failure came from a switch glitch. Now, we think the earlier and infrequent uncommanded thread cuts trained Mary to start very carefully to be very sure she wasn’t glitching the cutter’s hypothetical switch. Of course, her gradually increasing toe pressure moved the slider very slowly through its idle-to-running transition: she was optimizing her behavior to produce exactly the resistance required to trigger the cutter.

She now sets the machine’s speed control midway between Turtle and Hare to limit its top speed, presses the pedal with more confidence to minimize the time spent passing through the danger zone, and has had far few uncommanded thread cuts. We think it’s now a matter of retraining her foot to stomp with conviction; there’s no hardware or software fix.

I’m sure Juki had a good reason to select the resistances they did, but I would have gone for a non-zero minimum resistance at the fast end of travel and a zero-resistance switch to trigger the cutter.

Home Ec, Machine Shop, Photography & Images, Software

Photo Backdrop Clamp Pad Embiggening

We got a photo backdrop stand to hold Mary’s show-n-tell quilts during her quilting club meetings, but the clamps intended to hold the backdrop from the top bar don’t work quite the way one might expect. These photos snagged from the listing shows their intended use:

Emart Photo Backdrop - clamp examples
Emart Photo Backdrop – clamp examples

The clamp closes on the top bar with the jaws about 15 mm apart, so you must wrap the backdrop around the bar, thereby concealing the top few inches of whatever you intended to show. This doesn’t matter for a preprinted generic backdrop or a green screen, but quilt borders have interesting detail.

The clamps need thicker jaws, which I promptly conjured from the vasty digital deep:

Spring Clamp Pads - PS preview
Spring Clamp Pads – PS preview

The original jaws fit neatly into those recesses, atop a snippet of carpet tape to prevent them from wandering off:

Spring Clamp pads - detail
Spring Clamp pads – detail

They’re thick enough to meet in the middle and make the clamp’s serrated round-ish opening fit around the bar:

Spring Clamp pads - compared
Spring Clamp pads – compared

With a quilt in place, the clamps slide freely along the bar:

Spring Clamp pads - fit test
Spring Clamp pads – fit test

That’s a recreation based on actual events, mostly because erecting the stand wasn’t going to happen for one photo.

To level set your expectations, the “Convenient Carry Bag” is more of a wrap than a bag, without enough fabric to completely surround its contents:

Emart photo backdrop bag
Emart photo backdrop bag

I put all the clamps / hooks / doodads in a quart Ziploc baggie, which seemed like a better idea than letting them rattle around loose inside the wrap. The flimsy pair (!) of hook-n-loop straps don’t reach across the gap and, even extended with a few inches of double-sided Velcro, lack enough mojo to hold it closed against all the contents.

It’ll suffice for our simple needs, but …

The OpenSCAD source code as a GitHub Gist:

// Clamp pads for Emart photo backdrop clamps
// Ed Nisley KE4ZNU Jan 2021
/* [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);
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,$fn=Sides);
}
//----------------------
// Dimensions
OEMpad = [24.0,16.0,3.0]; // original pad
Pad = [35.0,25.0,8.0 + OEMpad.z]; // pad extension
PadOffset = [0,-3.0,0];
CornerRad = 3.0; // corner rounding
Gap = 3.0;
//----------------------
// Shape the pad
module BigPad() {
difference() {
hull()
for (i=[-1,1],j=[-1,1],k=[-1,1])
translate([i*(Pad.x/2 - CornerRad),j*(Pad.y/2 - CornerRad),k*(Pad.z/2 - CornerRad) + Pad.z/2])
sphere(r=CornerRad,$fn=6);
translate(PadOffset + [0,0,Pad.z - (OEMpad.z + Protrusion)/2])
cube(OEMpad + [HoleWindage,HoleWindage,Protrusion],center=true);
}
}
//----------------------
// Build a pair
translate([0,(Pad.y + Gap)/2,0])
BigPad();
translate([0,-(Pad.y + Gap)/2,0])
rotate(180)
BigPad();
view raw Spring Clamp Pads.scad hosted with ❤ by GitHub
COVID-19, Machine Shop

Straightening Armature Wire

Although I was blithely unaware when I bought some useful-looking surplus, it turns out 1/16 inch armature wire works really well to seal our homebrew masks around our noses. Mary added a narrow passage along the top edge of her slightly reshaped Fu Mask pattern to retain the wire and I provided 4.5 inch lengths of straightened wire:

Armature wire - stock vs. straightened
Armature wire – stock vs. straightened

The wire comes off the roll in dead-soft condition, so I can straighten (and slightly harden) it by simply rolling each wire with eight fingertips across the battered cutting board. The slightly wavy wire shows its as-cut condition and the three straight ones are ready for their masks.

Although nearly pure aluminum wire doesn’t work-harden quickly, half a year of mask duty definitely takes its toll. This sample came from my biking mask after the edges wore out:

Armature wire - work-hardened
Armature wire – work-hardened

We initially thought using two wires would provide a better fit, but more metal just made adjusting the nose seal more difficult after each washing. The wire has work-hardened enough to make the sharper bends pretty much permanent; they can be further bent, but no longer roll out under finger pressure.

Although we’re not yet at the point where we must reuse wires, I took this as an opportunity to improve my annealing hand: heat the wire almost to its melting point, hold it there for a few seconds, then let it cool slowly. The usual technique involves covering the aluminum with something like hand soap or permanent marker ink, heat until the soap / marker burns away, then let it air-cool. Unlike steel, there’s no need for quenching or tempering.

Blue Sharpie worked surprisingly well with a propane torch:

Armature wire - annealed straightened
Armature wire – annealed straightened

As far as I can tell after a few attempts, the pigment vanishes just below the annealing temperature and requires another pass to reach the right temperature. Sweep the flame steadily, don’t pause, and don’t hold the wire over anything melt-able.

Those wires (I cut the doubled wire apart) aren’t quite as soft as the original stock, but they rolled straight and are certainly good enough for our simple needs; they’re back in the Basement Laboratory Warehouse for future (re)use.

Machine Shop

Quilting Hexagon Template Generator: Knobless Half-Triangle

Although I’d put the same knob on the half-triangle end piece template as on the equilateral triangle template for piecing hexagons into strips, Mary decided a flat chip would be easier to use:

Quilting Hex Template - family - knobless half-triangle
Quilting Hex Template – family – knobless half-triangle

Bonus: you can now flip it over to cut the other half-triangles, if you haven’t already figured out how to cut two layers of fabric folded wrong sides together.

While I was at it, the knob on the triangle became optional, too. Flipping that one doesn’t buy you much, though.

The OpenSCAD source as a GitHub Gist has been ever so slightly tweaked:

// Quilting - Hexagon Templates
// Ed Nisley KE4ZNU - July 2020
// Reverse-engineered to repair a not-quite-standard hexagon quilt
// Useful geometry:
// https://en.wikipedia.org/wiki/Hexagon
/* [Layout Options] */
Layout = "Build"; // [Build, HexBuild, HexPlate, TriBuild, TriPlate, EndBuild, EndPlate]
//-------
//- Extrusion parameters must match reality!
// Print with 2 shells
/* [Hidden] */
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleFinagle = 0.2;
HoleFudge = 1.00;
function HoleAdjust(Diameter) = HoleFudge*Diameter + HoleFinagle;
Protrusion = 0.1; // make holes end cleanly
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
inch = 25.4;
//-------
// Dimensions
/* [Layout Options] */
FinishedWidthInch = 2.75;
FinishedWidth = FinishedWidthInch * inch;
SeamAllowanceInch = 0.25;
SeamAllowance = SeamAllowanceInch * inch;
TemplateThick = 3.0;
TriKnob = true;
EndKnob = false;
/* [Hidden] */
FinishedSideInch = FinishedWidthInch/sqrt(3);
FinishedSide = FinishedSideInch * inch;
echo(str("Finished side: ",FinishedSideInch," inch"));
CutWidth = FinishedWidth + 2*SeamAllowance;
CutSide = CutWidth/sqrt(3);
echo(str("Cut side: ",CutSide / inch," inch"));
// Make polygon-circles circumscribe the target widths
TemplateID = FinishedWidth / cos(180/6);
TemplateOD = CutWidth / cos(180/6);
/* [Hidden] */
TriRadius = FinishedSide/sqrt(3);
TriPoints = [[TriRadius,0],
[TriRadius*cos(120),TriRadius*sin(120)],
[TriRadius*cos(240),TriRadius*sin(240)]
];
echo(str("TriPoints: ",TriPoints));
EndPoints = [[TriRadius,0],
[TriRadius*cos(120),TriRadius*sin(120)],
[TriRadius*cos(120),0]
];
echo(str("EndPoints: ",EndPoints));
TipCutRadius = 2*(TriRadius + SeamAllowance); // circumscribing radius of tip cutter
TipPoints = [[TipCutRadius,0],
[TipCutRadius*cos(120),TipCutRadius*sin(120)],
[TipCutRadius*cos(240),TipCutRadius*sin(240)]
];
HandleHeight = 1 * inch;
HandleLength = (TemplateID + TemplateOD)/2;
HandleThick = IntegerMultiple(3.0,ThreadWidth);
HandleSides = 12*4;
StringDia = 4.0;
StringHeight = 0.6*HandleHeight;
DentDepth = HandleThick/4;
DentDia = 15 * DentDepth;
DentSphereRadius = (pow(DentDepth,2) + pow(DentDia,2)/4)/(2*DentDepth);
KnobOD = 15.0; // Triangle handle
KnobHeight = 20.0;
//-------
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(r=HoleAdjust(FixDia)/2,h=Height,$fn=Sides);
}
//-------
// Hex template
module HexPlate() {
difference() {
cylinder(r=TemplateOD/2,h=TemplateThick,$fn=6);
translate([0,0,-Protrusion])
cylinder(r=TemplateID/2,h=(TemplateThick + 2*Protrusion),$fn=6);
}
for (i=[1:6/2])
rotate(i*60)
translate([0,0,TemplateThick/2])
cube([HandleLength,HandleThick,TemplateThick],center=true);
}
module HexHandle() {
difference() {
rotate([90,0,0])
scale([1,HandleHeight/(TemplateOD/2),1])
rotate(180/HandleSides)
cylinder(d=HandleLength,h=HandleThick,center=true,$fn=HandleSides);
translate([0,0,-HandleHeight])
cube([2*TemplateOD,2*TemplateOD,2*HandleHeight],center=true);
translate([0,HandleThick,StringHeight])
rotate([90,090,0])
rotate(180/8)
PolyCyl(StringDia,2*HandleThick,8);
for (j=[-1,1]) {
translate([0,j*(DentSphereRadius + HandleThick/2 - DentDepth),StringHeight])
rotate(180/48)
sphere(r=DentSphereRadius,$fn=48);
}
}
}
module HexTemplate() {
HexPlate();
HexHandle();
}
//-------
// Triangle template
module TriPlate() {
linear_extrude(height=TemplateThick)
intersection() {
offset(delta=SeamAllowance) // basic cutting outline
polygon(points=TriPoints);
rotate(180)
polygon(points=TipPoints);
}
}
module TriTemplate() {
union() {
if (TriKnob)
cylinder(d=KnobOD,h=KnobHeight,$fn=HandleSides);
TriPlate();
}
}
//-------
// End piece template
module EndPlate() {
linear_extrude(height=TemplateThick)
intersection() {
offset(delta=SeamAllowance) // basic cutting outline
polygon(points=EndPoints);
rotate(180)
polygon(points=TipPoints);
}
}
module EndTemplate() {
union() {
if (EndKnob)
translate([0,(TriRadius/2)*sin(30),0])
cylinder(d=KnobOD,h=KnobHeight,$fn=HandleSides);
EndPlate();
}
}
//-------
// Build it!
if (Layout == "HexPlate")
HexPlate();
if (Layout == "HexBuild")
HexTemplate();
if (Layout == "TriPlate")
TriPlate();
if (Layout == "TriBuild")
TriTemplate();
if (Layout == "EndPlate")
EndPlate();
if (Layout == "EndBuild")
EndTemplate();
if (Layout == "Build") {
translate([1.5*TriRadius,-TriRadius,0])
rotate(180/6)
TriTemplate();
translate([-1.5*TriRadius,-TriRadius,0])
rotate(180/6)
EndTemplate();
translate([0,TemplateOD/2,0])
HexTemplate();
}
view raw Quilting Hex Template.scad hosted with ❤ by GitHub
Home Ec, Machine Shop, Science, Software

Quilting Hexagon Template Generator

Mary took on the task of finishing a hexagonal quilt from pieced strips, only to discover she’ll need several more strips and the myriad triangles required to turn hexagons into strips. The as-built strips do not match any of the standard pattern sizes, which meant ordinary templates were unavailing. I offered to build a template matching the (average) as-built hexagons, plus a triangle template based on those dimensions.

Wikipedia has useful summaries of hexagon and equilateral triangle geometry and equations.

Quilters measure hexes based on their finished side length, so a “1 inch hex” has sides measuring 1 inch, with the seam allowance extending ¼ inch beyond the sides. It’s difficult to measure finished sides with sufficient accuracy, so we averaged the side-to-side distance across several hexes.

Some thrashing around produced a quick-and-dirty check piece that matched (most of) the stack of un-sewn hexes:

Quilting Hexagon Cutting Template
Quilting Hexagon Cutting Template

That one came from a knockoff of the circle template, after some cleanup & tweakage, but failed user testing for not withstanding the side force from the rotary cutter blade. The inside and outside dimensions were correct, however, so I could proceed with some confidence I understood the geometry.

Both the pattern width (the side-to-side distance across the inside of the hex) and the seam allowance appearing in the Customizer appear in inches, because that’s how things get measured outside the Basement Laboratory & Fabrication Facility:

FinishedWidthInch = 2.75;
FinishedWidth = FinishedWidthInch * inch;

SeamAllowanceInch = 0.25;
SeamAllowance = SeamAllowanceInch * inch;

You feed in one side-to-side measurement and all other hex dimensions get calculated from that number; quilters default to a ¼ inch seam allowance. Remember, standard quilt hexes are measured by their side length, so just buy some standard templates.

This is one of the few times I’ve needed triangle graph paper:

Hex Quilting Template - geometry doodles
Hex Quilting Template – geometry doodles

After I gave up trying to get it right on square-grid paper, of course.

Solidifying those relations:

Quilting Hex Template - build layout
Quilting Hex Template – build layout

Then math got real:

Hex Quilting Templates - on strips
Hex Quilting Templates – on strips

Both templates have non-skid strips to keep the fabric in place while cutting:

Hex Quilting Template - grip strips
Hex Quilting Template – grip strips

I should have embossed the size on each template, but this feels like a one-off project and YAGNI. Of course, that’s how I felt about the circle templates, so maybe next time I’ll get it right.

As it turned out, Mary realized she needed a template for the two half-triangles at the end of each row:

Quilting Hex Template - half-triangle
Quilting Hex Template – half-triangle

It’s half of the finished size of the equilateral triangle on the right, with seam allowance added all around. The test scrap of fabric on the left shows the stitching along the hypotenuse of the half-triangle, where it joins to the end-of-row hexagon. Ideally, you need two half-triangle templates, but Mary says it’s easier to cut the fabric from the back side than to keep track of two templates.

The family portrait now has three members:

Quilting Hex Template - family
Quilting Hex Template – family

The OpenSCAD source code as a GitHub Gist:

// Quilting - Hexagon Templates
// Ed Nisley KE4ZNU - July 2020
// Reverse-engineered to repair a not-quite-standard hexagon quilt
// Useful geometry:
// https://en.wikipedia.org/wiki/Hexagon
/* [Layout Options] */
Layout = "Build"; // [Build, HexBuild, HexPlate, TriBuild, TriPlate, EndBuild, EndPlate]
//-------
//- Extrusion parameters must match reality!
// Print with 2 shells
/* [Hidden] */
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleFinagle = 0.2;
HoleFudge = 1.00;
function HoleAdjust(Diameter) = HoleFudge*Diameter + HoleFinagle;
Protrusion = 0.1; // make holes end cleanly
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
inch = 25.4;
//-------
// Dimensions
/* [Layout Options] */
FinishedWidthInch = 2.75;
FinishedWidth = FinishedWidthInch * inch;
SeamAllowanceInch = 0.25;
SeamAllowance = SeamAllowanceInch * inch;
TemplateThick = 3.0;
TriKnob = true;
EndKnob = false;
/* [Hidden] */
FinishedSideInch = FinishedWidthInch/sqrt(3);
FinishedSide = FinishedSideInch * inch;
echo(str("Finished side: ",FinishedSideInch," inch"));
CutWidth = FinishedWidth + 2*SeamAllowance;
CutSide = CutWidth/sqrt(3);
echo(str("Cut side: ",CutSide / inch," inch"));
// Make polygon-circles circumscribe the target widths
TemplateID = FinishedWidth / cos(180/6);
TemplateOD = CutWidth / cos(180/6);
/* [Hidden] */
TriRadius = FinishedSide/sqrt(3);
TriPoints = [[TriRadius,0],
[TriRadius*cos(120),TriRadius*sin(120)],
[TriRadius*cos(240),TriRadius*sin(240)]
];
echo(str("TriPoints: ",TriPoints));
EndPoints = [[TriRadius,0],
[TriRadius*cos(120),TriRadius*sin(120)],
[TriRadius*cos(120),0]
];
echo(str("EndPoints: ",EndPoints));
TipCutRadius = 2*(TriRadius + SeamAllowance); // circumscribing radius of tip cutter
TipPoints = [[TipCutRadius,0],
[TipCutRadius*cos(120),TipCutRadius*sin(120)],
[TipCutRadius*cos(240),TipCutRadius*sin(240)]
];
HandleHeight = 1 * inch;
HandleLength = (TemplateID + TemplateOD)/2;
HandleThick = IntegerMultiple(3.0,ThreadWidth);
HandleSides = 12*4;
StringDia = 4.0;
StringHeight = 0.6*HandleHeight;
DentDepth = HandleThick/4;
DentDia = 15 * DentDepth;
DentSphereRadius = (pow(DentDepth,2) + pow(DentDia,2)/4)/(2*DentDepth);
KnobOD = 15.0; // Triangle handle
KnobHeight = 20.0;
//-------
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(r=HoleAdjust(FixDia)/2,h=Height,$fn=Sides);
}
//-------
// Hex template
module HexPlate() {
difference() {
cylinder(r=TemplateOD/2,h=TemplateThick,$fn=6);
translate([0,0,-Protrusion])
cylinder(r=TemplateID/2,h=(TemplateThick + 2*Protrusion),$fn=6);
}
for (i=[1:6/2])
rotate(i*60)
translate([0,0,TemplateThick/2])
cube([HandleLength,HandleThick,TemplateThick],center=true);
}
module HexHandle() {
difference() {
rotate([90,0,0])
scale([1,HandleHeight/(TemplateOD/2),1])
rotate(180/HandleSides)
cylinder(d=HandleLength,h=HandleThick,center=true,$fn=HandleSides);
translate([0,0,-HandleHeight])
cube([2*TemplateOD,2*TemplateOD,2*HandleHeight],center=true);
translate([0,HandleThick,StringHeight])
rotate([90,090,0])
rotate(180/8)
PolyCyl(StringDia,2*HandleThick,8);
for (j=[-1,1]) {
translate([0,j*(DentSphereRadius + HandleThick/2 - DentDepth),StringHeight])
rotate(180/48)
sphere(r=DentSphereRadius,$fn=48);
}
}
}
module HexTemplate() {
HexPlate();
HexHandle();
}
//-------
// Triangle template
module TriPlate() {
linear_extrude(height=TemplateThick)
intersection() {
offset(delta=SeamAllowance) // basic cutting outline
polygon(points=TriPoints);
rotate(180)
polygon(points=TipPoints);
}
}
module TriTemplate() {
union() {
if (TriKnob)
cylinder(d=KnobOD,h=KnobHeight,$fn=HandleSides);
TriPlate();
}
}
//-------
// End piece template
module EndPlate() {
linear_extrude(height=TemplateThick)
intersection() {
offset(delta=SeamAllowance) // basic cutting outline
polygon(points=EndPoints);
rotate(180)
polygon(points=TipPoints);
}
}
module EndTemplate() {
union() {
if (EndKnob)
translate([0,(TriRadius/2)*sin(30),0])
cylinder(d=KnobOD,h=KnobHeight,$fn=HandleSides);
EndPlate();
}
}
//-------
// Build it!
if (Layout == "HexPlate")
HexPlate();
if (Layout == "HexBuild")
HexTemplate();
if (Layout == "TriPlate")
TriPlate();
if (Layout == "TriBuild")
TriTemplate();
if (Layout == "EndPlate")
EndPlate();
if (Layout == "EndBuild")
EndTemplate();
if (Layout == "Build") {
translate([1.5*TriRadius,-TriRadius,0])
rotate(180/6)
TriTemplate();
translate([-1.5*TriRadius,-TriRadius,0])
rotate(180/6)
EndTemplate();
translate([0,TemplateOD/2,0])
HexTemplate();
}
view raw Quilting Hex Template.scad hosted with ❤ by GitHub
Home Ec, Machine Shop

Kenmore 158 Sewing Machine: More Deglaring

My first pass at deglaring the shiny metal parts on Mary’s brightly lit Kenmore 158 used translucent mailing labels on the “hand hole cover” in front of the needle:

Kenmore 158 - non-glare cover plate
Kenmore 158 – non-glare cover plate

That worked surprisingly well for surprisingly long, but the edges eventually came loose and, after far too long, I deployed the Tiny Sandblaster™:

Kenmore 158 - matte cover plate - feet
Kenmore 158 – matte cover plate – feet

The mottled matte effect isn’t quite what I expected, but it’s better-looking in person and we deemed it Good Enough™ for the purpose.

You saw the foot on the left in the previous effort:

Kenmore 158 - matte cover plate - feet - detail
Kenmore 158 – matte cover plate – feet – detail

The rounded plate directly under the needle sits far enough back to not reflect any of the LEDs toward her normal operating position, so we decided it didn’t need sandblasting.

She now has plenty of light where she needs it, with no glare from the metal bits.

Home Ec, Machine Shop

HON Lateral File Cabinets: Rekeying

You’d hope the original owner would tape a key inside each file cabinet before donating it to charity; ours arrived unlocked and without keys. Fortunately, eBay sellers have All The Keys and I ordered replacement keys for each cabinet.

One pair of new keys fit into their lock, but the shoulder didn’t seat properly and the key didn’t turn:

HON Lateral File - 125E key insertion
HON Lateral File – 125E key insertion

Compared with a key for the other cabinet (on the bottom), it seems the tip profile wasn’t quite the same:

HON Lateral File - 125E key tip
HON Lateral File – 125E key tip

Perhaps the underside of the tip hadn’t been cut? Stacking the two keys makes it even more obvious:

Key 125E tip shaping - vs Key 101E
Key 125E tip shaping – vs Key 101E

The eBay seller suggested the lock cores have changed over the years, as other (unaltered) keys fit current cabinet locks. Perhaps HON used fussy high-quality lock cores back in 2004 when they built these cabinets.

I gingerly filed the 125E key’s tip to match the 101E key and, after several iterations, the shoulder seated firmly in the lock and the core turned smoothly. Flushed with success, I marked the other key of the pair, filed to the mark, and it worked on the first try.

Mary doesn’t plan to store any secret fabrics in her new cabinets, but now I can declare victory and move on.