Sunday, July 24, 2011

CHAIR REPAIR

My desk chair here at Roseholme Cottage's ground floor Retrotechnologist HQ (as opposed to the basement ham shack and workbench) is a fair match to my big old oak desk: it's an old-fashioned wooden desk chair, assembled from a kit over a decade ago.

As the years have passed, it has picked up both "character" and damage, the latter being a broken screw holding a stabilizing metal piece to one of the legs of the "truck," and subsequent damage to the 3/8" hanger bolt that fastens that leg to the hollow central post. The result was a rolling chair that tended to go caterwampus without constant attention.

Last week, the lagscrew half of the hanger bolt chewed up the last of the wood it was screwed into -- which meant that tightening the nut and bolt half just pulled the thing loose.

It was time to take action. The stabilizing piece problem, which I had long attributed to the screw bottoming out against the hanger bolt, turned out to be a broken-off part of the original screw. Since it was at 90 degrees to the hanger bolt, that meant there was a fairly simple fix. Here's what it looks like:The fix is hidden: I drilled out the broken screw and glued in a section of dowel, right under the tab on the circled portion; it was more than long enough to intersect and replace the wood worn away where the hanger bolt had been chewing at it, and since I used a 3/4 dowel, wide enough for that job too.

You can see where I scratched up the wood finish on the underside of the leg, trimming the dowel with a flush-cutting saw.

Since there was a little bit of chewed-out hanger-bolt hole left, I drilled it out, too, just enough to have a flat-bottomed hole in which to glue in another short dowel to fill it.

(There's a trick to getting a better bond with smooth dowels: take a pair of slip-joint pliers with nice teeth and notch up the dowel so it will have a rougher surface. Of course, always clamp it it in place while the glue dries).

Twelve hours later, once the glue had dried, I trimmed the dowels flush, held the leg in place and marked it for the stabilizing screw, drilled and installed that screw and then used a pencil stub to mark the bigger hole for the hanger bolt. Drilled that square (by eye), screwed the hanger bolt in, reassembled and hooray, I had a chair again.

But there's one trick here that I didn't tell you. Did you notice? Hint: it just about requires one of these: Remember that broken-off screw? How'd I drill that out of much softer wood -- making a 3/4" hole, yet -- without some kind of damage to the drill "bit,"* the wood or myself, hey?

I cheated. I dodged it. If you have a drill press, you can clamp the work to the table, take the centering drill out of a hole saw of the proper size, and zzipp! drill around the offending bit of metal. The plug broke off at the level of the worn-out hole for the hanger bolt and a sharp 1/2" wood chisel made short work of the remainder.

The little centering drill is there on a hole saw for a reason. Unless you have amazing upper body strength, you can't hold the thing steady while it cuts without it. But a drill press and a good clamp will do the job and make it seem easy.

On the subject of hole saws, shop tricks and "making it look easy," Starrett makes a hole saw arbor (that's the part that holds the cylindrical saw) that replaces the centering drill and allows the assembly to hold two hole saws concentrically. It's an "oops" arbor, for when you holesawed too small a hole; it centers the new size on the mistaken size. They're inexpensive, too -- I figure mine paid for itself the first time I needed it and had it.

(For the observant: yes, my tabletop press has some surface rust. It was a little that way when I bought it. I'm working it over with oil and brass brushes but I haven't got it all yet. I got the table, the base, the chuck and made a start on the column -- need a bigger brush, I was using a worn-out bore brush).
_______________________
* If it has a square or hex cross-section shank and goes in a brace, you call it a bit. Otherwise, those hole-making spun-around thingies you chuck up in press or a hand drill are themselves drills. "Drill bit" is a horrid neologism.

Monday, July 18, 2011

ENTER THE LINEDRAGON

(I couldn't resist the title).

What's a "LineDragon?" It's a way of supporting vertical feeders for a balanced transmission line and getting them around the roof overhang and gutters. Sunday, I designed and installed the Mk. III:Mark I was a simple section of unpainted 1/2" plywood screwed to one of the joists (or are they rafters?). It worked but it was off-center to the natural drape of the line. A season's worth of weather left it with a permanent skew and wanting to delaminate. Mark II was the center section of the present edition and a 2x4 spacer, but even it wasn't close enough to where it needed to be, so I got out the good miter saw and a drawing pad and ended up with what you see. Short 2x4s screwed to the joists support transverse pieces that in turn hold two more short sections that support the upright, this time in line with the straight-line path between the feedpoint of my G5RV double-Zepp antenna and the feed-through insulators that bring it into my basement ham shack.

The vertical portion, with its "mouth" holding one of the spreader insulators,* bears a resemblance to the prow of a Viking ship and thus, the LineDragon!

More details: You can clearly see the insulator being "chomped." It is held in place by the tension on the feedline leading on up to the center of my antenna (there's another little cheat up the way, a kind of X-brace that carries it clear of the peak of the roof).

Here's the view from below. I installed the 2x4s on the joists first, tacked the transverse pieces in place, then found the proper position for the support assembly by trial and error, clamped it to the transverse pieces and removed it as an assembly to install the fasteners holding that subassembly together. The way, I did the bare minimum of trying to hold parts in place overhead with one hand while driving screws with the other. Even cheating with a battery drill, that's way too much effort!

All done in a mad rush to get it installed before my house-painter returns on Tuesday. I'm probably going to be shooing birds out of it next Spring.

Feel free to borrow and adapt the idea behind this gadget, if it's something you could use.
____________________________
* Simply short lengths of semi-rigid irrigation tubing, with holes drilled to clear the wire and narrow "V" cuts so you can snap it in. This clever idea -- and the all-one-wire antenna and feedline -- was invented, developed and sold by the late Gary Gomph, W7FG; his antennas and line live on at True Ladder Line, as does his callsign at the Gomph Memorial Radio Club. (Another memorial page at this link). W7FG also founded Vintage Manuals, Inc. He'd sold it a few years before his untimely passing and it's still around.

Sunday, July 17, 2011

STANCOR 10P TRANSMITTER

Only a few hams owned them, but there were quite a few different commercially-built and kit amateur radio transmitters available between WW I and WW II, especially in the 1930s.

Transformer companies were a particularly fertile source, especially for the smaller, simpler rigs. Thordarson offered a few, Meissner sold the "Signal Shifter" VFO/low-power transmitter; Utah had a cute little 6L6 job (and I think one or two larger ones) and a couple of other firms got in on the multi-company (and higher-power) "All Star" transmitter kit. Stancor was right there, too, with a whole range of transmitters from flea power through at least several hundred Watts, both CW (Morse) and AM (Voice).

The Stancor 10P was either the smallest or the next-smallest, with a 6J5 crystal oscillator driving a 6L6 final, modulated by another 6L6. An '80 did the power supply honors and the whole thing was so cute as to be very nearly twee:Only 10-¾" wide, 6-½" tall and 6-¼" deep, it weighs in at a remarkable 14 pounds. This one came my way at a reasonable price thanks to good luck (and recognizing what it was) at one of the large auction sites. It arrived with fairly complete provenance, tracing it back to the original owner through the late W2WHW, who was the last boatanchor-fan ham to own it before me.

At some point before it graced his hamshack, it was heavily modified with the intent of curing interference to analog television; this was a big problem in the 1950s but was mooted by improvements in TV sets and, ultimately, by digital TV. So I can do what it appears from his notes that '2WHW had planned, and gently return the little transmitter to as close to original condition as possible.It is always handy to have a schematic; this one has had the original white-on-black scheme inverted for more cost-effective print-out. Even more information, including a full parts list, may be found from K7JRL. (Who has a very results-oriented website, an excellent resource!)

I have most of the passive components on order from Antique Electronic Supply and will be posting updates as the project proceeds.

Saturday, July 16, 2011

RETROTECHNOLOGIST VISITS NATIONAL MOTO+CYCLE

After a thoroughly satisfactory breakfast at a local diner, Tam K and I set out to visit National Moto+Cycle, whose storefront may be found in the same 1920s building as Luna Music and Indie Bike (around the corner). They already had eye-candy waiting out front: It's even prettier up close, though the guys were quick to point out that this is a prototype, lacking the custom paint and trim the production models will have. (Notice the helmets in the window, of which I should have taken a closer photo).

Inside, Chief Designer Matty Bennett and his partner-in-vehicularity were waiting and filled with enthusiasm.

National's basic product is a bicycle, but one that hearkens back to the first two decades of the 20th Century, as the "safety bicycle" was at its peak and the first production motorized versions were appearing. But they use modern materials with far better strength-to-weight properties, to produce a bicycle of reasonable weight and retro looks. The race-style turned-down handlebars can be flipped, resulting in a classic recreational/practical bike, or replaced with even more upright "beach cruiser" style handlebars. The bike has a multi-speed kickback hub and optional disc brake system.

...Or you can add a motor! Matty describes it as "like an early production motorized cycle. They're not intended to go superfast," running at the same speeds as city traffic. He plans to add an electric version as well. (More info at this link). The internal-combustion version has a standard twist throttle, kill switch and hand brake.

Sidecars will be available for all versions -- they'll be kept lightweight, in keeping with National's goal of attractive, retro, useful vehicles. As you can see, even the showroom is something of a design engineer's dream.

Both the name and the logo are not a new invention but the return of a very old Indianapolis automaker: between 1900 and 1924, the National Motor Vehicle Company built a successful line of internal-combustion and electric vehicles in their plant at 22nd and the Monon (rather a lot of photos here); the building still stands and is presently The Project School.

Matty himself is the eye and hand behind the look of a number of Broad Ripple institutions, not the least of which is Taste. Between that talent, his background in bicycling, enthusiasm for these bikes and the history of National, I think we're looking at a winner.

I've more photos, from National Moto+Cycle's secret basement proving grounds, but they must wait for another day.

Friday, July 15, 2011

RETRO WHEELS

I have recently found a couple of builders of classic bicycles, one British (Pashley Cycles) and one American (Worksman Cycles, who even make pennyfarthings). Each one offers wonderful bikes, delightfully characteristic of their national traditions. I was thinking it couldn't get any better.

It got better.

Just down the road from my 1924 bungalow -- well, just down the road, around several corners and a few blocks over, which is still quite close -- is a brand-new business, gearing up to offer a product right out of time: National Moto+Cycle builds motorized cycles of the sort that haven't been made in nearly a hundred years. Just click through their "wall photos." You'll see.

My lodger says I stared at the screen, stunned, when I first saw them.

We're got an invitation to stop by tomorrow. I can't make any promises but I will be bringing my camera.

Wednesday, July 13, 2011

HAMFEST FIND

I like this -- and for a dollar, how could I go wrong?United Television Laboratories was, it turns out, a tech school in Lousiville, KY; searching for them turns up a fascinating blog post, with a promotional audio clip and a lot of memories from graduates. "UTL" gave way to "United Electronics Institute" some time in the 1950s; eventually, UEI declined but in their heyday, the school (supposedly, I can't confirm it) even ran its own UHF TV station! (At one time, FCC handed out UHF TV licenses practically for the asking -- and even at that, not all of them made a go of it.)

A version of the meter even showed up in some of their magazine ads. It looks a lot like a Triplett prewar 666-H VOM, both inside and out; if I can find mine, I'll post a photo for comparison, later: (Similar one here). The specific arrangement, with the "OHMS" zero-adjust and pin jacks above the meter, was only used in a few models of Triplett's 666 and it is very likely the United Televison Labs meter is a clone. Update: Or, on reflection, maybe not; at least not of mine, which, Triplett-like, has but a single mode-changing switch. Some earlier versions of the 666 did have an AC/DC selector, though.(Later versions of Triplett's compact meter retained the test-lead lacks at top, in a case otherwise similar to their top of the line VOM, which is still in production).

Though the front panel is a bit bent and some of the hardware is loose, the meter movement seems to have some life in it and if it's intact and the meter rectifier (copper-oxide, a bit difficult to replace) is okay, the VOM can probably be brought back with a little bench time and elbow grease.

Sunday, July 3, 2011

CLOCK LINKS

Some interesting finds this evening.

Older readers may remember the self-winding, centrally-synchronized Western Union clocks, big clocks (face 14" or so in diameter), often with a square wooden case, bearing the company name and proud assurance, "NAVAL OBSERVATORY TIME," often over a red lighting bolt just so you wouldn't miss the point. Radio stations used them, if they could afford the service, (sometimes leading to surprised announcers if the clock was a little off when Western Union sent the synchronizing impulse and the thing skipped ahead during a station break!) and they weren't too uncommon in offices and shops.

They're still around -- they were built to last -- and Ken's Clock Clinic specializes in fixing them. The clocks typically used a couple of big old #6 dry cell "batteries"* and he offers both straight-up replacements for the dry cells and nifty versions that use modern electronics to provide the synchronizing signal, too. (Alas, his repair bench is very busy -- but he does have a waiting list).

Those #6 dry cell replacements are of interest to old-radio folks, too (and even antique telephone hobbyists, since the older types used a local battery to run the carbon microphone; that's what the lower compartment of a wooden wall phone is for). There are other sources, some very authentic with a little effort but the more, the better.

Another old clock you might remember is the Telechron. These wall clocks, in 10" and larger sizes, usually have a small dot about midway between the center and 12 that goes red for 12 hours and white the next, to mark p.m. and a.m. The little 60-cycle synchronous motor uses a sealed rotor and it takes serious skill to open one up and get it running again. And, yes, there's a fellow who does just that, at TelechronClock.com. (I wonder if he would tackle the noisy motor unit from my Numechron Tymeter mechanical digital clock?)
___________________________
* A misnomer, since they consist of a single, large dry Leclanché cell. A battery would be more than one. The irony is, modern #6 "cells" contain 2 or more F or D cells in parallel: they really are batteries.