The Search is Over

I finally got some time to polish off the Navy search light I've been "restovating." I had completed the shutter and tested the lamp, but the shutter let too much light through. I fixed that by adding a narrow piece of extruded aluminum to each shutter. This had several laudable effects:

• It's more like the original shutter design. 
• As the photo below shows, light leakage is minimal.
• The finished edge of the shutter looks better, 
• The added mass smooths out the operation.

 


A few other details had  to be attended to, like installing a handle and figuring out and recreating  the return spring.

US Navy Searchlight Update: The Signal Shutter

I am just now finding the time to work on the last and most difficult part of this restorvation; the signal shutter.  I found the unit with only the center actuator shaft and most of the signal lever components, but not a single shutter or critical hinge component.

Thanks to the work of  Chris Hunter. Curator of Collections and Exhibitions. Schenectady Museum: Suits-Bueche Planetarium (GE's corporate headquarters), I received this close up photo of the shutter.

It appeared to me that the small hinged parts are cast.  As you can see the design uses the shutter itself to support the side hinge plates "paddles"(also cast?).   The end pieces rotate in the brass cylinders visible from the exterior.

I had a different idea; to run shafts across the entire width and hang the shutters on the shafts.  My reasoning was to make the action as light as possible.  By hanging the shutters I could relatively light aluminum instead of steel.  And since I am not normally one who works with metal or has any metal working tools, the softer the metal the better.

Still, the problem of the cast hinges remained.  I landed on the idea of making my version out of two halves of extruded aluminum angle.

Full size stencils of the hinges glued to the aluminum angle.

One rough pair with the four mounting holes drilled.  A second pair is in the 

makeshift jig.  Well at least if the holes aren't all square at least they are the same.

Each pair (there are eight of them) took up to an hour to make... and they are not even done yet.

A rough cut pair foreground and a rough finished pair background.

There are four sets each side of center, but the center one is different (almost like a butterfly valve0.  From the photos it is clear that the shutters are all in the same plane when closed.  My solution meant the upper and lower shutters would be on different planes.  How to construct the middle piece was something I had been struggling with.  I decided to build the 8 pieces and then use them as a physical model of the problem.

This I did and a solution popped out rather quickly.  It's not like the original, but it is sturdy and simple.  I mocked it up and eventually had enough pieces to see if it worked.  It does as the video shows.  It's a bit noisy and loose, but then again it's not complete or final yet... but this was a major hurdle overcome..

US Navy Searchlight Update: 1000 Watts

Thanks to the work of  Chris Hunter. Curator of Collections and Exhibitions. Schenectady Museum & Suits-Bueche Planetarium (GE's corporate headquartes), I have some pretty great drawings of searchlights like the 12G30, but not the 12G30 itself.  Like this one that shows the bulb mounting.

From other sources I suspect that it used a 1000 watt incandescent light.  It's a whopper, and this type of bulb is not available anymore.  To stay true to the idea, I decided to use a mogul 2-pin, G38 base.  It is rated at an astounding 50 amps at up to 1000 volts.  But as the photo below shows below, it's also huge (The G38 base is the white, ceramic block about the size of a pound of butter). 

The base got bigger since the searchlight was first built, but the bulbs have gotten smaller.  Halogen bulbs can put out as much light in less space.  But to keep in the spirit of the original, I decided to order the tallest G38 bulb that I could find.   The result is a Ushio, 1000 Watt, 8" tall Halogen bulb.  Much of that is the ceramic holder (shown above).

The first mounting platform I built had adjustable height and depth, but it was too tall but 2 to 3 inches.

The second version (shown in the photos) gives up height adjustment, but adds depth adjustment during operation.  Being able to move the light source closer or farther from the parabolic reflector narrows or widens the beam spread.

Adjustment is acomplished by the small wheel (the round thing in front that looks like a bicycle gear) connected to a 1/2" threaded rod (actually a sawed off carriage bolt) that drives the sled the G38 base sits on.  There are two slits in the bottom of the searchlight housing.  I'm not sure what they were for(drainage?).  but the wheel drops through one of them to allow adjustment during operation.

And it works:

1000 watts is bright.  Blindingly bright.

 

 

In This photo the light is shining through my workshop door and out to a tree about 50 yards away.  I walked down to it and I could have easily read a newspaper or a map by the ambient light.  Once I move it outside, then I'll be able to see how bright it is a half a mile away or more.

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Next and final stop' The shutter/signal system.

U.S. Navy 12G30 Searchlight Restovation: Getting My Bearings

The searchlight body sits in a yoke that permits up and down motion.  I was surprised to to find this accomplished via a set of ball bearings. 

Below left is the new bearing (Nice) and to the right, one of the two old ones; the one that survived intact..  One can clearly see written on it, "Hoffman," Made in England" and "ULS SE".  I was amazed to find that these numbers could still be cross-referenced to a modern replacement pair. 

The bearing mounted in its hub with a new nut retaining it.

The hub cap installed.  I used acorn nuts; they are more decorative and also cover what would otherwise be an exposed bolt end.  I can't recall what was in the center of the hub (I think either nothing or just a bolt), but I added the grease fitting

US Navy Type 12G30 Aldis Signal Lamp Restoration

 I found this navy signal lamp in a barn on a farm I bought in 2002.  It looked interesting enough that I didn't scrap it along with all the other metal junk I found.  For 9 years it continued to sit in the barn playing host to mice, but otherwise undisturbed.  This year, for reasons I do not know, I decided it had languished long enough.

Shown below partially disassembled and already cleaning had already commenced.  Just by way of saying it looked worse when I first started in on it.

I call it a "restovation" project.  That is, it is part restoration, part renovation.  I am not after perfect fidelity to the original and I wont be opposed to "improving" the original design.

These photos simply show the degree of corrosion a layers of battleship gray paint.

Above is the shutter open/close control for the signalling function.  This navy lamp, built by General Electric (GE) was a generic body to which could be attached a spotlight or floodlight lens or a Morse code signalling shutter.  Unfortunately this and the casing waa all that was present.  All the shutters had been removed.

Although most everything was frozen in rust, covered in paint or severely pitted by exposure, there was one notable exception.  After I dumped out a decade's accumulation of mouse droppings, and after I had unstuck the back cover, I opened it up to reveal the parabolic reflector looking nearly as good as the day it was installed. 

I believe the reflector to be a 1/8" thick, solid piece of optically ground stainless steel.  If the rest of the lamp wasn't worth salvaging, it would make an awesome serving dish.

Above is the shutter housing.  The brass plugs that look like bullet casings are laid out in the center.  They were a bear to  remove.  Two are missing on the right.  One is being repaired and one was so stuck I was forced to destroy it to get it out. 

The "After" shot above is a good summary of the restovation.  Restored are the component parts and the contour of the lamp.  Renovations included replacing the brass, regular head set screws with stainless steel socket head cap screws.  And most noticeably painting the body blue; navy blue.  On a battleship great care is taken to have no shiny, reflective surfaces.  Thus everything was coated in layers of gray paint.  I was under no such constraints and so I picked a color that would be a good contrast to the brass.

I broke one tab off the die-cast handle while pounding out one of the frozen bolts.  You can see the "J.B/ Weld" line in the photo. The complicated gasket that ran in the holes is replaced by a simple piece of cork.  In general there seemed to be noble attempt to waterproof the lamp, but plenty of drain holes in recognition that it would fail.

I also broke off the left cover hinge tab.  To repair I drilled a hole through the two parts and inserted a brass rod along with copious amounts of JB weld.  The small circle of brass is the filed down end of the rod.  I also made such a mess of the holes in the hinge arms that I had to drill them out to 3/8" and put in 3/8" to 1/4" reducing bushings in all four!  The are floating in a bed of JB Weld with the threaded rod keeping them aligned as it sets.

The elevation "protractor" and mounting plate refreshed and ready to go.  The small, regular, slot-head, brass screws replaced by phillips head stainless steel.  Oh, and every threaded part has been retapped or cleaned up with a die and reassembled with anti-seize goop to make future dis-assembly a snap.

The other side of the shutter housing and the leading edge of the lamp obviously took a beating facing the weather.  In the original design a die-cast ring apparently sat in a bed of a black, tar-like substance and supported the backside of the glass.  The cast-bronze ring was then embedded in more of this goop and bolted to the front with no gasket between them.

The ring was so decrepit, bent and broken that I dispensed with it entirely.  Instead I used automotive door edge guard to cover up the decayed edge of the shutter ring and provide a gasket to the bronze retaining ring.

The old glass was intact but cloudy from probably decades of exposure to salt spray.  The new glass was glued with silicone directly to the front trim ring.  This solid bronze cast ring bearing the name "General Electric" their logo and "Made in USA" was in great shape.  In part this was due to another ring that sat on top of it and must have supported a cover or filters or both.  It was in such bad shape I abandoned it and in any case this trim ring is the part I want to be fully exposed.

The unit partially reassembled to test fit and finish. Except for the plugs and machine screws, all the other brass and bronze parts were polished up, but then painted with Krylon Copper Foil Metal spray paint.  This covers some of the pits and defects in the originals and reduces  maintenance task of having to polish the rough castings.  The clevis pins and thumb screws were also painted, though they are steel.

The front of the unit with the start of my attempt to recreate the shutter system in the form of aluminum tubes.

Looking into the unit with the mirror installed.  The four rusted retaining clips now replaced with six aluminum ones.

Remaining tasks:  New bearings so I can mount it on the yoke, determining and acquiring the light source, and building and installing the shutter system.