Tag: Improvements

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

Screw Thread Measurement

While I was cutting threads for the Floor Lamp poles, I tried measuring my progress over wires:

Floor Lamp – tube fitting – thread measurement

Those are three lengths of music wire, slightly bent from their storage roll, held in place with a ~~precision clamp~~ metric micrometer. Given the crudity of the setup, the uncalibrated wire diameter, and my lack of thread-fu, the results came out both close and unconvincing.

A set of real thread measuring wires being cheap & readily available, I’m prepared for the next time around this block:

Thread Measuring Wires – eBay set

The 185 mil “wires” (they’re all allegedly ground rod) will let me cut threads matching things like a Jesus nut; they’re suited for 3 TPI / 8 mm pitch screws. Mostly, wires from the front row will be all I ever need.

Which look like this in action:

Thread Measuring Wires – eBay setThread Measuring Wires – detail

The black doodad (the set includes half a dozen for all the wire sizes) fits over the micrometer anvil and holds two wires betwixt anvil and screw, leaving me to manipulate the screw, the third wire, and the micrometer with my remaining hands. Hence the vise holding the micrometer, which is known to be Very Bad Practice.

From the side:

Thread Measuring Wires – overview

All of the smaller wires measure 0.5 mil too thin, which is likely due to my lack of calibrated measurement equipment:

Thread Measuring Wires – scant 24 mil

The few thread pitch diameters I measured also came out slightly too small, again likely due to calibration and screw tolerances.

The LittleMachineShop description of measuring threads over wires seems entirely adequate.

To forestall link rot, a slightly rearranged version of their tables of wire constants:

Thread Wire Measurement Constants

The lower table has metric thread pitches with the wire sizes in inches.

You measure the distance over the recommended wire (in inches or millimeters, as appropriate), subtract the constant, and get the pitch diameter in the same units. Conversely, add the constant to the desired pitch diameter to get the target over-wire distance, carefully cut the thread until it measures a bit less than that, back up sixty seconds, and cut it spot on.

Verily, it is written: there is no UnDo key (⎌) in machine shop work.

2020-06-05

PiHole with DNS-over-HTTP: Revised

More than a year later, the PiHole continues to work fine, but the process for installing the Cloudflare DoH machinery has evolved.

(And, yes, it’s supposed to be DNS-over-HTTPS. So it goes.)

To forestall link rot, the key points:

cd /tmp ;  wget https://bin.equinox.io/c/VdrWdbjqyF/cloudflared-stable-linux-arm.tgz
tar -xvzf cloudflared-stable-linux-arm.tgz 
sudo cp cloudflared /usr/local/bin
sudo chmod +x /usr/local/bin/cloudflared
sudo cloudflared -v
sudo useradd -s /usr/sbin/nologin -r -M cloudflared
sudo nano /etc/default/cloudflared
----
CLOUDFLARED_OPTS=--port 5053 --upstream https://1.1.1.1/dns-query --upstream https://1.0.0.1/dns-query 
----
sudo chown cloudflared:cloudflared /etc/default/cloudflared
sudo chown cloudflared:cloudflared /usr/local/bin/cloudflared
sudo nano /etc/systemd/system/cloudflared.service
----
[Unit]
Description=cloudflared DNS over HTTPS proxy
After=syslog.target network-online.target

[Service]
Type=simple
User=cloudflared
EnvironmentFile=/etc/default/cloudflared
ExecStart=/usr/local/bin/cloudflared proxy-dns $CLOUDFLARED_OPTS
Restart=on-failure
RestartSec=10
KillMode=process

[Install]
WantedBy=multi-user.target
----
sudo systemctl enable cloudflared
sudo systemctl start cloudflared
sudo systemctl status cloudflared

Then aim PiHole’s DNS at 127.0.0.1#5053. It used to be on port #54, for whatever that’s worth.

Verify it at https://1.1.1.1/help, which should tell you DoH is in full effect.

To update the daemon, which I probably won’t remember:

wget https://bin.equinox.io/c/VdrWdbjqyF/cloudflared-stable-linux-arm.tgz
tar -xvzf cloudflared-stable-linux-arm.tgz
sudo systemctl stop cloudflared
sudo cp ./cloudflared /usr/local/bin
sudo chmod +x /usr/local/bin/cloudflared
sudo systemctl start cloudflared
cloudflared -v
sudo systemctl status cloudflared

And then It Just Works … again!

2020-06-03

Garden Hose Valve Wrench: Reinforced

After five gardening seasons, my simple 3D printed wrench broke:

Hose Valve Knob - fractured — Hose Valve Knob – fractured

Although Jason’s comment suggesting carbon-fiber reinforcing rods didn’t prompt me to lay in a stock, ordinary music wire should serve the same purpose:

Hose Valve Knob - cut pins — Hose Valve Knob – cut pins

The pins are 1.6 mm diameter and 20 mm long, chopped off with hardened diagonal cutters. Next time, I must (remember to) grind the ends flat.

The solid model needs holes in appropriate spots:

Hose Valve Knob - Reinforced - Slic3r — Hose Valve Knob – Reinforced – Slic3r

Yes, I’m going to put round pins in square holes, without drilling the holes to the proper diameter: no epoxy, no adhesive, just 20 mm of pure friction.

The drill press aligns the pins:

Hose Valve Knob - pin ready — Hose Valve Knob – pin ready

And rams them about halfway down:

Hose Valve Knob - pin midway — Hose Valve Knob – pin midway

Close the chuck jaws and shove them flush with the surface:

Hose Valve Knob - pins installed — Hose Valve Knob – pins installed

You can see the pins and their solid plastic shells through the wrench stem:

Hose Valve Knob - assembled — Hose Valve Knob – assembled

Early testing shows the reinforced wrench works just as well as the previous version, even on some new valves sporting different handles, with an equally sloppy fit for all. No surprise: I just poked holes in the existing model and left all the other dimensions alone.

The OpenSCAD source code as a GitHub Gist:

	// Hose connector knob
	// Ed Nisley KE4ZNU – June 2015
	// 2020-05 add reinforcing rods

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

	RodHoles = true;

	//- Extrusion parameters – must match reality!

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	Protrusion = 0.1;

	HoleWindage = 0.2;

	//——
	// Dimensions

	/* [Dimensions] */

	RodOD = 1.6;
	RodAngle = 35;

	/* [Hidden] */

	StemOD = 30.0; // max OD for valve-to-valve clearance

	BossOD = 16.0; // single-ended handle boss

	SlotWidth = 13.0;
	SlotHeight = 10.0;

	StemInset = 10.0;
	StemLength = StemInset + SlotHeight + 25.0;
	StemSides = 2*4;

	Align = 0180/StemSides; // 1 produces thinner jaw ends

	KnobOD1 = 70; // maximum dia without chamfer
	KnobOD2 = 60; // top dia

	KnobSides = 4*4;

	DomeHeight = 12; // dome shape above lobes

	KnobHeight = DomeHeight + 2*SlotHeight;

	DomeOD = KnobOD2 + (KnobOD1 – KnobOD2)*(DomeHeight/KnobHeight);

	DomeArcRad = (pow(KnobHeight,2) + pow(DomeOD,2)/4) / (2*DomeHeight);

	RodBCD = (StemOD + BossOD)/2;

	//- Adjust hole diameter to make the size come out right

	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=(FixDia + HoleWindage)/2,h=Height,$fn=Sides);
	}

	//– Stem for valve handles

	module Stem() {

	difference() {
	rotate(Align)
	cylinder(d=StemOD,h=StemLength,$fn=StemSides);
	translate([0,0,SlotHeight/2 – Protrusion/2])
	cube([2*StemOD,SlotWidth,(SlotHeight + Protrusion)],center=true);
	translate([0,0,-Protrusion])
	cylinder(d=BossOD,h=SlotHeight,$fn=2*StemSides);
	if (RodHoles)
	for (i=[-1:1])
	rotate(i*RodAngle + 90)
	for (j=[-1,1])
	translate([j*RodBCD/2,0,-Protrusion])
	rotate(180/4)
	PolyCyl(RodOD,2*SlotHeight,4);
	}

	}


	//– Hand-friendly knob

	module KnobCap() {
	difference() {
	scale([1.0,0.75,1.0])
	rotate(180/KnobSides)
	intersection() {
	translate([0,0,(KnobHeight-DomeArcRad)])
	sphere(r=DomeArcRad,$fa=180/KnobSides);
	cylinder(r1=KnobOD1/2,r2=KnobOD2/2,h=KnobHeight,$fn=KnobSides);
	cylinder(r1=KnobOD2/2,r2=KnobOD1/2,h=KnobHeight,$fn=KnobSides);
	}
	translate([0,0,-Protrusion])
	rotate(Align)
	cylinder(d=(StemOD + 2*ThreadWidth),h=(StemInset + Protrusion),$fn=StemSides);
	}
	}

	//- Build it


	if (Layout == "Knob")
	KnobCap();

	if (Layout == "Stem")
	Stem();

	if (Layout == "Build") {
	translate([-KnobOD1/2,0,0])
	KnobCap();
	translate([StemOD/2,0,StemLength])
	rotate([180,0,0])
	Stem();
	}

	if (Layout == "Show") {
	translate([0,0,0])
	Stem();
	translate([0,0,StemLength – StemInset])
	KnobCap();
	}

view raw Hose Connector Knob.scad hosted with ❤ by GitHub

2020-06-02

Beaver Dam: More Timber!

Team Beaver continues to add logs, branches, and mud to their dam beside the Dutchess Rail Trail:

Beaver Lodge and Dam – DCRT N of Golds Gym – 2020-05-26

Apparently they’re now busy raising a bunch of little beavers inside the lodge. Next year we expect the water will begin rising in other marshes along the rail trail.

Go, beavers, go!

2020-05-31
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

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

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

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.

2020-05-28
Floor Lamp: Rattle-Can Black

Shooting the modified copper elbow with gloss black atop gray primer definitely improved its disposition:

Floor Lamp – painted elbow – installed

I’d have been more inclined to apply several light coats if the wind weren’t blowing up a storm. As it was, I shot enough black to cover the not-quite-dry primer (“top coat at any time”) and called it a day.

The scuffed tubes aren’t quite that ugly in person, but they have suffered some abuse along the way. Seen from a normal working distance, however, it’s all good:

Floor Lamp – finished

The lamp isn’t quite as tippy as I feared, so I’ll try it without the broken truck spring counterweight until something untoward happens.

I loves me some happy ending …

2020-05-22
Floor Lamp: Threaded Fittings

The reshaped copper elbow on the floor lamp now has the right angle, but lacks threaded connections to the tubes. The OEM tube threads are close to M15×1, thus prompting the change gear exercise persuading Tiny Lathe™ to cut metric threads.

Chuck up a length of 5/8 inch aluminum tube, clean up the end, and poke a thread runout slot into it:

Floor Lamp – tube fitting – thread runout

Turn the soon-to-be-thread OD to 14.7 mm, well under the minimum 14.794 mm major thread diameter. I figure it’s better to match the existing not-quite-standard tube threads than to get all fussy about tolerances:

Floor Lamp – tube fitting – thread OD

Drill out the tube to 27/64 inch = 0.422 inch = 10.7 mm, a bit larger than the OEM fittings, to easily pass the JST-SM connector I added so I could take the lamp apart:

Floor Lamp – tube fitting – drilling bore

Yeah, you’re not supposed to let the swarf build up like that, but it’s hard to stop when you’re getting good chip.

Break the sharp edges:

Floor Lamp – tube fitting – ready for threading

Set up for threading:

Floor Lamp – tube fitting – external threading setup

That’s a really nice Warner laydown threader I won as a Cabin Fever door prize quite some years ago.

A comprehensive discussion of threading may be handy.

The compound is at 90° to the cross slide, because the DRO housing doesn’t let the compound swivel to the proper angle for thread cutting. I’m just ramming the threader straight into the tube, taking sissy cuts, and hoping for the best.

Kiss the OD with the cutter, set the cross slide DRO to zero, position the cutter just off the end of the tube, close the split nuts around the leadscrew, engage the threading dial at a conspicuous mark:

Mini-Lathe Threading Dial – aligned

The first real pass looked good:

Floor Lamp – tube fitting – first thread pass

The runout slot is 1/16 inch = 1.6 mm wide and I’m running the lathe dead slow, so there’s plenty of time to punch the STOP button as the cutter enters the slot and let the spindle coast down. Flip the switch to REVERSE, crank the cross slide out a turn (1 mm with 0.3 mm of crank backlash), run the cutter back to the starting point, crank the cross slide in, and iterate until the fitting screws into one of the OEM lamp tubes:

Floor Lamp – tube fitting – final thread

The 5/8 inch tube is just a smidge too small for the copper fitting, so knurl the fitting to enlarge the OD slightly more than a smidge:

Floor Lamp – tube fitting – knurled

Break the knurl edges, part off the fitting, clean up the new end, and do it all over again:

Floor Lamp – tube fitting – threaded adapters

The knurls got filed down to an exact slip fit in the copper elbow and will eventually be epoxied in place.

The cut-off tube on the lamp head also needs internal threads, so bore out the interior to flatten the weld seam:

Floor Lamp – tube fitting – cleaning tube bore

No pix of the threading, but you have the general idea; the tube wall is a scant 0.6 mm thick, so this isn’t the place for full-spec threads. I stopped when the OEM tube screwed in place.

Apart from the hideous solder job, it came together pretty well:

Floor Lamp – tube fitting – unpainted

It’s much more stable than Kapton-wrapped tubes jammed into a bare copper fitting, although that’s not saying much.

A rattle-can finish seems appropriate …

2020-05-21