The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Improvements

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

Inexpensive Diamond-Frame Bike Seat Tube Finishing

Seat Tube Fitting

Our daughter has been helping a friend learn to ride a bike (at age 15: it’s never too late!) and we’ve been rehabilitating a new-to-her bike in the process. It’s an inexpensive Ross bike, perfect for the task at hand, and is providing a good introduction to machine-shop work.

The fact that it’s much older than she is makes not a whit of difference. Nay, verily, I rode a bike pretty much like this one for hundreds & hundreds of miles back in the day. I got better ones when I could afford them and she will, too; maybe we’ll tempt her into a recumbent bike some day…

Anyhow, the seat tended to spin around even with the clamp cranked dangerously tight. Taking a look down the tube showed that they used welded-seam tubing (it really was an inexpensive bike) and didn’t bother to clean up the internal seam. As a result, the chromed steel seat post rested on maybe three small patches of metal that didn’t provide much friction at all.

I wrapped a neodymium magnet in a rag and stuffed it down the tube to catch the filings, then applied a coarse cylindrical file (a rat-tail would work as well) to the seam. When it was nearly flush, I switched to a finer file to smooth it and the other high spots. The picture shows the improved seam, ready for the seat post. Ugly, but rough is actually a Good Thing in this situation.

Seat Clamp Swaging

The seat tube has a nominal 1-inch OD, so I clamped a random round from the heap in the vise, tapped the clamp around it, and massaged it lightly with a hammer to persuade it into a more cylindrical shape. It’s still not perfect, but at least the bolt lugs engage the seat tube around the slit somewhat better.

With all that in hand, the seat post is now perfectly secure.

On her first “I can ride!” parking-lot outing, she experimentally determined that a bicycle wheel’s lowest-energy state resembles the edge of a potato chip. Fortunately, it was the front wheel and, after a bit more shop derring-do than one might wish, we swapped in another wheel that’s been hanging on the garage wall for a decade, ready for just such an occasion.

Remember how independent your first bike made you feel? It’s working that way for those two, just like it did for us. Life is full of bumps and they’ll get hurt every now and then, but there’s no other way to get through it; they’re just about ready to ride over the horizon.

Happy Independence Day for those of us in the USA!

2009-07-04
Plug Alignment for ICOM IC-Z1A Radio

Plugs and jack alignment plates

As I mentioned there, I originally connected my bicycle-mobile amateur radio gadget to the ICOM IC-Z1A radio using separate mic and speaker plugs. That seemed like a good idea, but bicycles vibrate a lot and the plugs apply enough leverage to the jacks inside the radio to pry them right off the PCB. That requires a protracted repair session that I never wanted to do again.

The solution is to mount both plugs rigidly on the radio so that they simply can’t move. I dithered for a while and finally decided that function trumps good looks on this project, particularly given that our radios spend their entire lives inside a bag behind the bike seats.

The top picture shows the small aluminum plates I made to align the plugs to the HT jacks, along with a plastic gluing fixture to hold the plugs parallel while the epoxy cures. If you just jam the plugs into the radio without an alignment fixture, you will glue the plugs together in such a way that they cannot be removed: the radio does not hold the shafts exactly parallel!

Plug stabilization – What Not To Do

How do I know? Well, I tried doing exactly that by simply epoxying the existing plugs into place, applying enough epoxy putty to stabilize the plugs against the radio. Looks reasonable, but when it came time to take them out (and you will want to take them out, trust me) they are firmly and permanently embedded. I had to carve them apart to get them out.

The mic, speaker, and coaxial power jacks are 10 mm on center. The 2.5 mm mic plug has a small shoulder that required a matching recess in the plate, while the 3.5 mm speaker plug is basically a cylinder. I don’t use the coaxial power jack, having hacked an alkaline battery pack with Anderson Powerpoles. The plate’s external contour matches the flat area atop the radio around the jacks.

You could lay out and drill close-enough holes by hand, use a step drill to make the shoulder recess, and then let the epoxy do the final alignment. However, you want the center-to-center distance exactly spot-on correct, as the plugs won’t mate properly otherwise. I turned it into a CNC project for my Sherline mill, of course, but that’s just because I have one.

HT Plugs in gluing fixture

This picture shows two plugs epoxied into the plate. While the epoxy cures, the plate rests atop the fixture with the two plugs vertical and their shell flanges flush against it. I applied the epoxy with a toothpick and worked it into the gap between the threads and the plate.

The end result will be a pair of plugs that exactly match the radio’s jacks in a plate that sits firmly atop the radio’s case. You should find that the plugs snap firmly into place and the entire assembly is absolutely rigid.

Caveat: don’t use an aluminum plate if your radio depends on separate electrical connections for the mic and speaker plug shells. The IC-Z1A has isolated shells, but remains happy when they’re connected. My Kenwood TH-F6A HT uses the shells for entirely different functions and will not work with them shorted together.

With the epoxy cured, wire the connections as usual. I had a small cable with enough tiny wires to put the mic conductors in their own shielded pair, but that’s likely overkill.

Finished plugs with epoxy blob

You could machine a nice enclosure, but I simply molded an epoxy putty turd around the connections, shells, and cable. The trick is to wait until it’s nearly cured, plug it into the radio, then shave off whatever gets in the way of the knobs, antenna plug, and other appurtenances.

It may not look elegant, but it works great!

2009-06-27
Tour Easy Rear Brake Noodle Extension

Noodle Extension and Parts

Our Tour Easy recumbents have linear-pull brakes on the rear and, for some reason, the noodle on Mary’s bike didn’t quite clear the frame: the cable bent slightly around the frame when the brake was active.

That made the brake difficult to adjust, as linear-pull brakes depend on an exact balance between the restoring springs on each side. With the cable pulling to the right, the left-side pad would contact the rim first and give the brake lever a mushy pull until the right-side pad clamped down.

A quick lathe session applied to some nylon scrap turned out an extension tube that fit between the steel noodle and the (slightly broken) plastic hoodickie that engages the brake arm. I used nylon (or something slippery like that) to make sure the cable wasn’t going to bind on it.

Epoxy Potting

The noodle originally fastened into the plastic hoodickie with a small collar that snapped into a pair of holes, but I took a shortcut: JB Kwik Epoxy. The shank end of a small drill slip-fit into the hoodickie’s cable passage kept the extension aligned while the epoxy set up. The masking tape prevented the epoxy from drooling out through the two small holes: the cured epoxy plug will have a pair of retaining posts in exactly the right places. The smears on the plastic parts chipped right off, not that anybody will ever notice.

I’m depending on spring force to hold the noodle in the extension, which seems to be working just fine. This is one of those jobs where everything’s under compression all the time and the cable tension ensures good alignment.

The socket on the extension’s fat end is a snug fit to the collar swaged on the noodle; other noodle varieties seem to have other sorts of ends, so check to make sure this will work for you.

Noodle Extension Installed

Added Brake Cable Clearance

These pix show the brake assembly from below (the paint failed on the frame cross-member early on and I’ve been meaning to slather some rust converter on that spot for years. Sigh.) and the now-positive clearance between the brake cable and the frame with the brake applied.

And, for future reference, the dimensions…

Noodle and Extension Dimensions

2009-06-22
Bird Box Entrance Reducer

Wren-sized entrance reducer in place

We put out bird boxes to encourage more House Wrens, but House Sparrows often take over the boxes. This year we kept the boxes down until the sparrows had already started their nests in the bushes, hoping that the wrens would get a head start on their nests. Two days after we put the boxes up, we had a nesting pair of wrens… and two days later a pair of sparrows had evicted them and were installing their own nest.

Rechecking the box specs, it seems wrens prefer a hole somewhere between 7/8″ and 1-1/8″, but I’d drilled 1-1/2″ holes for bluebirds (a long time ago, before we knew bluebirds vastly preferred the edges of open fields). Making a hole larger is easy, making one smaller is more difficult.

Cutting off the barb

I thought of making a wood bushing, then came to my senses: a 3/4″ thick wood ring with 1/4″ walls just wasn’t going to work. Given that the wrens (or their ancestors or relatives) have already tried nesting in our gardening boots, bicycle helmets, and tool trays, I figured they wouldn’t be too fussy about the material around their entrance hole.

To the Basement Laboratory Machine Shop Wing!

The parts heap disgorged a box of huge hose barb fittings, one of which had a 1.1″ ID and a 1.4″ OD: close enough. I parted off 3/4″ from the end of the barb, using a bit not really suited for the purpose that gave a nearly perfect edge in the soft plastic. One swipe with a deburring tool and it’s done.

Bushing ready to install

A few wraps of duct tape provided a nice press fit and a springy retaining force without gluing the barb in place. This is pretty, mmmm, barbaric, but if it survives one nesting cycle I’ll do something much nicer.

Time is definitely of the essence here, as we fear the wrens have been driven away: we haven’t heard them since their eviction. I did three boxes in about half an hour; we’ll see what transpires.

The bottom pic shows the box from the front yard, where Downy Woodpeckers nested for a few years. They thought the hole needed a bit of renovation… and they have the tools for the job!

2009-06-18
Quieter Luggage

Muted zipper pull tabs

Luggage now comes with a pair of sliders on each zipper, which means that the two sliders come together when the zipper is closed. That allows you to lock the slider pulls together, which is a nice touch for those of you who think luggage locks actually improve security.

It also means that the metallic pull tabs jingle and jangle merrily together in the back of the van all the way to grandmother’s house as we go, we go.

Not to be tolerated, sez I.

Apply a length of heat shrink tubing to each tab. If you’re a locking kind of person, leave the holes on the end exposed. If you’re a real cheapskate, you could get away with shrinking just one tube per pair, but even I’m not that far gone.

2009-06-16
Phone Charger: PowerPole-to-USB Adapter

I have a Virgin Mobile Kyocera Marbl phone, for reasons discussed there. It’s sufficiently nonstandard that the “fits most phones” headsets and chargers don’t. In particular, I have yet to see a charger with the proper adapter dingus for this phone.

Fortunately, the charger is rated at 5 V @ 350 mA… that’s easy enough.

Phone charger with Powerpoles

Cut the charger’s cable in the middle, more or less, and install Anderson Powerpole connectors. The standard color code for 5 V is white / black; don’t use red / black for fear you’ll eventually plug it into a 12 V source and toast the phone.

The charger wires are most likely a far smaller gauge than the 15 A (!) connector pins prefer, so strip the conductors twice as long, double the ’em over and perhaps add a short length of multistrand hookup wire to fill out the barrel before you crimp it.

Check the polarity before you poke the pins in the housings: you want the +5 V pin in the white housing!

I aligned the housings to match the ARES / RACES standard, as described there, as that’s what I’ve done with all my other Powerpole connectors. If your phone expects some weird-ass voltage, maybe you want to make certain it can’t possibly mate with anything that’ll kill it stone cold dead. Oh, and in that case pick a suitably different color. Blue seems to be the standard for 9 V, at least in the ham radio arena, for whatever that’s worth.

Add heatshrink tubing for strain relief (it might slip over the finished pins if you forget), wrap cold-vulcanizing rubber tape around the whole connector for more strain relief, and you’re done. It’ll make your charger cable resemble an anaconda eating a pig, but that’s OK with me.

USB charger to phone cable

Now the phone can commune with a bench power supply, a bulk 5 V supply, or nearly anything that you’ve hacked into using Powerpoles. It’s your job to make sure the voltage matches up!

Now, if you haven’t already, make a USB-to-Powerpole adapter. Alas, even though the phone uses 5 V, it draws too much current to charge directly from a standard USB port. However, I have a Black & Decker Pocket Power battery pack with a regulated USB outlet that can allegedly supply 250 mA and seems to handle the phone just fine.

So: cut a spare USB cable, verify that the red conductor is 5 V and the black is common (hell hath no fury like that of an unjustified assumption and we’re dealing with bottom-dollar suppliers here), crimp, align housings, add strain relief, and try it out.

This should work for any phone with a dumb, bulk-power charger. If you cut the cable and find three conductors, solder that devil back together again; there’s no telling what’s passing along that third rail!

2009-06-15
Where To Put Too Many Clamps

Clamp storage plates on floor joist

Not in a drawer, that’s for sure…

Whack a narrow rectangle from some random scrap of thin wood-like substance, squirt hot-melt glue along one edge, stick it to the floor joist over your tool chest, align it pretty much horizontally, take two deep breaths while the glue solidifies, then neatly affix your clamps.

Repeat as needed when you get more clamps: you can never have enough clamps!

The red-handled spring clamps on the far right hang from a row of nails where, this being directly in front of my tool cabinet, they don’t quite knock me on the head. I really wish the original owner of this house had sprung for one more course of concrete block; another nine inches of headroom would have been just ducky.

2009-06-13