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Archive for category Machine Shop

Monthly Image: Belmar Bridge

About five miles south of Franklin PA along the Allegheny River Trail, the Belmar Bridge carries the Sandy Creek Trail over the Allegheny River:

Belmar Bridge - Rivets

Belmar Bridge – Rivets

The gap in the rivets along the main truss show where someone pried off the bronze plaque surely commemorating the bridge. The scarred surface suggests a bronze-steel battery was in effect for quite some time.

I’m a sucker for big ironwork:

Belmar Bridge - Truss Joint

Belmar Bridge – Truss Joint

It’s a look at engineering done in the days of slide rules and limited data, when overengineering wasn’t nearly as bad as ensuring the thing never, ever fell down.

The bolts holding the beams and struts together show considerable confidence:

Belmar Bridge - Ironwork - bolt detail

Belmar Bridge – Ironwork – bolt detail

Each bolt counts as single point of failure, but this one can rust for a long, long time before the risk becomes important.

Each of those gazillion rivets required a crew to heat white hot, shove into the hole, and hammer tight.

They don’t make ’em like that any more and I suppose it’s a good thing …

 

 

 

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M110A2 203 mm Self-Propelled Howitzer

It could be an M107 155 mm gun, but the double muzzle brake (the front vent is shadowed) identifies it as a mighty M110A2 203 mm self-propelled howitzer:

M110A2 203mm Self-Propelled Howitzer - York PA

M110A2 203mm Self-Propelled Howitzer – York PA

Back in the day, being 30 km away from a kiloton or ten of nuclear blast was deemed Far Enough, although nobody actually pulled the string to find out. Apparently, sections of surplus barrels make hella-good bunker buster bombs, at least when you’re in a hurry.

Obsolete, of course, explaining why it’s parked behind the York Agricultural and Industrial Museum, seen from the wonderful Heritage Rail Trail. We rode south from York almost to the the Maryland line, then back again; a good time was had by all.

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Baofeng UV-5 to Bike Helmet Wiring

Rather than 3D print and hand-wire a plug adapter to fit the socket around the Baofeng UV-5 mic and speaker jacks, I cheated:

Baofeng headset - harvested plug

Baofeng headset – harvested plug

Un-wearably bad Baofeng headsets now cost just over a buck apiece in lots of five, delivered halfway around the planet, and provide:

  • A compatible molded mic+speaker plug
  • A decent length of four-conductor cable with solder-meltable insulation
  • An unlistenably bad earbud on a stick
  • A lump with an electret mic and PTT switch
  • Various junk I’ll never use

The “hook earpiece” seems to have been designed by someone who had read the specs for a human head, but had never actually met a human being.

The wire colors from the dual plug, along with the wire colors for the repurposed USB cable to the headset, and the PTT connection:

Baofeng headset cable vs helmet cable - wire colors

Baofeng headset cable vs helmet cable – wire colors

Then wire it up accordingly:

Baofeng headset wire plate - first wiring

Baofeng headset wire plate – first wiring

The small heatstink tubing surrounding each connection isn’t easily visible, which, in the case of the ground / common lump, is a Good Thing. I chivied a strip of Kapton under the whole mess, folded it over on top, squished it together, then secured it with 1/4 inch tape extending over the plate edges. The cable ties stick out far enough to keep the joints from rubbing on anything; it’s not built to last for a thousand years, but should let us hear how this lashup works.

Now, to the bikes:

Baofeng headset wire plate - in use

Baofeng headset wire plate – in use

I’m convincing myself a little supporting ring under the SMA-to-UHF adapter won’t actually stabilize the precarious-looking joint.

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Baofeng UV-5 Headset Wiring Plate

My venerable amateur radio HT APRS-voice interfaces have recently begun failing and, given poor APRS coverage in Poughkeepsie due to having two iGates shut down (due to the aging radio geek population), I decided it’s time to simplify the radio interface. Given that HTs are designed to run with an external electret mic and earbud, the “interface” becomes basically some wires between the radio’s jacks, a repurposed USB plug on the bike helmet, and the PTT switch on the handlebar.

I expected to add a resistive attenuator to the earbud, but it wasn’t clear whether the mic would need an amplifier similar to the one in the APRS interface, so I decided to start as simply as possible.

The general idea is to anchor all the cables to a plate on the back of the radio, interconnect as needed, then “protect” everything with tape. The pocket clip has M2.5 screws on 26 mm (not 25.4, honest) centers, so that’s how it started:

Baofeng headset wire plate - dimensions

Baofeng headset wire plate – dimensions

The four holes beside the tabs will serve as starting points for rectangular notches holding cable ties lashing the wires to the plate:

Baofeng headset wire plate - drilled

Baofeng headset wire plate – drilled

Like this:

Baofeng headset wire plate - sawed

Baofeng headset wire plate – sawed

That’s hot and nasty, straight from the bandsaw.

After some edge cleanup, add obligatory Kapton tape to insulate stray wires from the aluminum:

Baofeng headset wire plate - installed

Baofeng headset wire plate – installed

The alert reader will note beveled corners on one plate and square corners on the other; think “continuous product improvement”.

The big rectangular gap in the middle of the plate provides (barely enough) finger clearance to push the battery release latch.

Now, to wire it up …

The dimensions of the recess surrounding the jacks on the Baofeng UV-5, just to have them around:

Baofeng headset jack socket - dimension doodle

Baofeng headset jack socket – dimension doodle

Which came from measurements of both the Wouxun and Baofeng radios:

Baofeng Wouxun headset jack sockets - measurements

Baofeng Wouxun headset jack sockets – measurements

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Specialized MTB Shoes vs. Shimano PD-M324 SPD Pedals

Long ago, I put Shimano PD-M324 pedals on Mary’s Tour Easy, because she prefers a pedal with a platform on one side and SPD cleats on the other.

Shimano PD-M324 pedal - SPD side

Shimano PD-M324 pedal – SPD side

Those are newish-old-stock from the Big Box o’ Bike Parts, as she’s worn out the previous pedals.

She recently got a pair of Specialized MTB shoes:

Specialized MTB Shoes - PD-M324 clearance

Specialized MTB Shoes – PD-M324 clearance

The shoes work fine with the more-or-less standard Shimano PD-M520 double-entry SPD pedals on my bike:

Shimano PD-M520 pedal

Shimano PD-M520 pedal

But the soles jammed against the frame on the PD-M324 pedals.

So I carved away enough rubber around the cleat sockets for clearance to float properly with the cleats latched. A bit of trial-and-error, probably with a bit more to come after on-the-road experience, but definitely a step in the right direction.

Protip: always always always arrange the workpiece so the blade trajectory cannot intersect any part of your body, no matter what slips occur.

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Know When to Stop Turning

Spotted on a motel room door:

Motel Door Peephole - cover whoopsie

Motel Door Peephole – cover whoopsie

I wonder if all the peepholes in the motel were installed with a similar lack of attention to detail; it was recently renovated, so this is new work.

For sure, they’ll never be properly adjusted …

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Herringbone Pinion Gears

These herringbone gears were part of updating my old Thing-O-Matic:

Herringbone gears with nut inserts

Herringbone gears with nut inserts

But, as the saying goes, that’s not a herringbone gear. This is a herringbone gear:

Bethlehem Steel - 48 inch rolling mill gears

Bethlehem Steel – 48 inch rolling mill gears

We always read the signage:

Bethlehem Steel - 48 inch rolling mill gears - description

Bethlehem Steel – 48 inch rolling mill gears – description

They’re parked in front of the National Museum of Industrial History in Bethlehem, PA.

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