Shuttles Board Game: Replacement Pegs

For reasons not relevant here, I made replacement pegs for the Shuttles board game:

Shuttles Game - solid model - Slic3r
Shuttles Game – solid model – Slic3r

Not the most challenging solid model I’ve ever conjured from the vasty digital deep, but 3D printing is really good for stuff like this.

The OEM pegs have a hollow center, most likely to simplify stripping them from the injection mold, which I dutifully duplicated:

Shuttles Game pegs - hollow - solid model
Shuttles Game pegs – hollow – solid model

It turns out the additional perimeter length inside the pegs requires 50% more printing time, far offsetting the reduced 10% infill. Given that each solid set takes just under an hour, I decided to lose half an hour of verisimilitude.

I plunked a nice round cap atop the OEM peg’s flat end, but stopped short of printing & installing a round plug for the butt end.

While the 3D printer’s hot, ya may as well make a bunch:

Shuttles game pegs
Shuttles game pegs

Game on …

The OpenSCAD source code as a GitHub Gist:

Update: They’re a bit too large, so the Gist now produces tapered pegs.

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:

Pan Lid Handle Quieting

A surprisingly heavy stainless steel pan lid from the local ReStore has only one fault: when placed upside-down on the counter while we’re tending the pan contents, it will rock back and forth for nearly a minute. The lid has a rubberized insert for finger protection:

Pan lid - original handle
Pan lid – original handle

However, the inserts cover only the side of the handle, so the metal arch rests on the counter. Setting it up in the shop let me scuff up the handle contact points:

Pan lid - contact point
Pan lid – contact point

Then some Dremel grinding wheel work recessed the handle just barely below the inserts and changed the arch enough to keep it off the counter:

Pan lid - recessed handle crest
Pan lid – recessed handle crest

The lid now stops rocking after a few seconds and is much quieter while doing so. It may require a bit more grinding, but it’s much better after this small intervention.

Makergear M2 V4 Nozzle: Silicone Refresh

After a year and a half, the silicone coat I’d applied to the M2’s nozzle had pretty much worn away, so I peeled off the remnants, buffed up the brass, and mushed on another coat:

Makergear M2 V4 Nozzle - High-temp silicone coat
Makergear M2 V4 Nozzle – High-temp silicone coat

The coverage isn’t even, particularly in the direction I can neither see nor reach with the hot end still in the printer, but it’s way less hassle than recalibrating the Z=0 position. The very thin layer over the brass around the nozzle will vanish immediately on the skirt surrounding the first part.

I should definitely recoat the nozzle more often, because PETG doesn’t stick to silicone nearly as well as it does to brass: a nice new coat makes the PETG burned-snot problem Just Go Away.

Can Opener Re-Gearing

Six years on, I just deployed the last of the aluminum spares from the original CNC project:

Can opener - new gear installed
Can opener – new gear installed

I swear the cutter gear on the left does not show that rust in person!

This can opener has a slightly larger bolt than the previous ones, so I embiggened the hole with a step drill:

Can opener - redrilling new gear
Can opener – redrilling new gear

Having run out of aluminum gears, I’ll be forced to make a hob to make a steel gear. Drat!

Motor Starting vs. Long Wires

A recent email conversation may prove relevant to someone else …

I have a pole barn which has approximately 100′ run of 10 gauge copper supplying power to the building. I … did not care to pay … $12,000 for a new 200′ line from the road … [with] only lights and 2 door openers for demand.

I … put a 30 gallon air compressor in […]. When I first put it in, it struggled to start @<40 F. They called it a 1.6 running h.p. (whatever that means) motor. Nameplate shows 15/7.5 F.L.A. I switched it to 240v and the problem went away.

Aren’t I likely to get the same problem as I had before or do 240 volt motors start easier?

I screwed up when they buried the wire – in retrospect I would have buried 6ga to the barn to lessen the voltage drop.

After running a few numbers, here’s what I came up with …

do 240 volt motors start easier?

The trouble with motors is they draw far more current while starting than they do while running. A factor of ten more is a good rule of thumb.

So a “1.6 running HP” motor draws 1.2 kW while running at full load:
 – 10 A at 120 V
 –  5 A at 240 V

The “full load amps” will be higher than that, because the motor isn’t 100% efficient. You can plug the FLA values into the calculation for an even more depressing result.

During the fraction of a second when it’s starting, however, it will (try to!) draw 100 A or 50 A, depending on which line voltage you’ve wired it for.

100′ run of 10 gauge copper

That’s 200 feet of wire out-and-back.

Look up the resistance per foot in a wire table, finding 10 AWG wire has a (convenient!) resistance of 1 mΩ/ft, so a 200 ft length has 0.2 Ω of resistance:

 – A 10 A load drops 2 V
 – A  5 A load drops 1 V

Both of which are survivable in normal operation at their respective line voltages.

However, the motor starting currents will be completely different. A 100 A current will (try to!) drop 20 V, reducing the line voltage to 100 V and stalling the motor. Running the motor from 240 V means the 50 A starting current drops only 10 V and the remaining 230 V can get the motor up to speed.

Now, 240 V service isn’t a complete solution. The new compressor draws 15 “full load amps”, so it’ll drop 3 V while it’s running and 30 V while starting. It’ll probably start at 210 V, but it may grunt for a bit longer than you like as the speed comes up and the current goes down.

in retrospect I would have buried 6ga to the barn

There’s a Pennsylvania Dutch saying: “We grow too soon old and too late smart.” [grin]