Wednesday, June 14, 2017

Reusing Antique Socket Interior

Any type of restoration should focus on improving the safety as well as the functionality of the object. For lighting, there have been major improvements in the last few decades in polarity and quality of materials. The plastic on mid-century lamp cords can deteriorate and crack exposing the wire. Today's plastics and insulation are much more durable and efficient.

The term lamp repair covers a large spectrum of possibilities from replacing a socket in the latest Flea Market find to complete restoration of a crystal chandelier. Knowing what parts to keep and what parts to replace can be tricky. As a general rule, we replace any wiring that might be over 20 years old. Newer wire can stay as long as it is polarized (plug has one small and one wide blade and the cord has one smooth wire and one ribbed wire) does not have any cracks, rubs, or exposed wire.

New Plug (left) Vs. Old Plug (right)

Specialty lighting shops, like Antique Lamp Supply, offer a large selection of lamp cord in different colors. You don't have to sacrifice the vintage look of a cord for a newer safer cord with a polarized plug. New lamp cord colors like antique brass, unfinished brass, and antique bronze help match an older fixture's finish. 

46716 - Antique Bronze Color Lamp Cord Set

46717 - Unfinished Brass Color Lamp Cord Set

46718 - Antique Brass Color Lamp Cord Set
Sockets are a little more complicated. There are several things to consider including size, age, functionality, and condition. As this blog has touched on, there are different size sockets available. In the US, for example, we only use 4 (E12, E26, E39, and GU24). If a lamp needs repair and it has an uncommon socket, it is getting replaced. 

For every repair we check the socket functionality. If it does not work properly it is going to be replaced. Occasionally, some corrosion can be removed and improve the socket's performance. Sockets are small mechanical parts and they were not designed to be repaired easily. 

The age of a socket would normally correlate with usage and material. As mentioned earlier, plastics made in the early to middle part of the 20th century have proven to deteriorate and are probably not safe. Some early sockets were made with porcelain interiors. With some simple tests, you can determine if the socket interiors can be reused.

Test the socket interior with an ohmmeter. Remove the socket interior from the socket shell and remove any wire on it. 

Touch the one line of the ohmmeter to the center tab inside the socket. Touch the other line to a screw terminal. Turn the socket switch a few times. If the ohmmeter does not react try the other screw terminal. 

The ohmmeter should indicate the screw terminal that links to the center of the socket and the switch is properly opening and closing the circuit (switching on and off). 

After you have identified the screw terminal that matches the center of the socket, mark the screw with a paint pen or marker. 

This establishes the polarity of the socket. Modern sockets have a nickel and brass screw terminal. The hot wire (smooth wire of a cord set, black wire, or wire that correlates to the small blade of a polarized plug) connects to the brass screw and powers the center tab of a socket. Older lamps did not have polarized sockets, plugs or wire. 

With a new paper insulator, this socket interior is tested and ready to be reused.

Wednesday, May 31, 2017

Socket Sizes and Bulb Shapes

Working on repairs, restorations and lighting creations, it is important to use products designed to fit the right application. A socket is not just a socket. It could be an E39 Keyless Porcelain Socket. And a bulb is not just a bulb. For the E39 socket you would need the right bulb to fit.

Fortunately, there are standards in the lighting industry where parts are built to spec. Pieces of an older lamp that fail can be replaced with an almost exact replacement part. Worn out sockets and switches can be replaced. Bulbs are manufactured to meet these same standards to fit the socket.

Bulb Shapes Explained

Bulb shapes are difficult to explain. The standards for bulb shape relate to the width, height, and curvature. For an A-19 bulb the A parts describes the shape and the 19 is the size of the bulb. For the A series bulbs, the width is measured in 1/8 inch and an A19 is 2 3/8 inch wide ( 19 times 1/8 inch). 

A-19, Standard base, all purpose house and appliance bulb

Other bulb shapes like the G, PS, CT, or T all describe the shape and the corresponding number is the size. These standards are part of the ANSI C79.1-2002 Nomenclature For Glass Bulbs Intended For Use With Electric Lamps. If you want to learn more, good luck with that journey. 

Socket Sizes Explained

Socket sizes follow a simpler rule of Type-Size. E type sockets are the most common. The E stands for Edison and designates a screw type socket. The size is a simple measurement of width in millimeters. An E26 socket (most common type) has an Edison thread interior and is 26 millimeters wide. This socket is also referred to as a Medium socket.

48226 - 3" Medium Base Keyless Candle Socket
The 3 most common sockets in the USA are the E12 (candelabra), E26 (medium) and the  E39 (mogul). As this table shows, there are some sockets in between these sizes. For traditional lighting, those three are the most commonly used.

DesignationBase major diameter (thread external)NameApplicationIEC 60061-1 standard sheet
E55 mmLilliput Edison Screw (LES)Indicator lights, decorative lights7004-25[12]
E1010 mmMiniature Edison Screw (MES)Flashlights, bicycle lights7004-22
E1111 mmMini-Candelabra Edison Screw (mini-can)120 V halogen mini-candelabra(7004-6-1)
E1212 mmCandelabra Edison Screw (CES), C7120 V candelabra/night lamp7004-28
E1414 mmSmall Edison Screw (SES)230 V candelabra/chandelier, night lamps, and some pendant lights.7004-23
E1717 mmIntermediate Edison Screw (IES), C9120 V appliance7004-26
E2626 mm[Medium] (one-inch) Edison Screw (ES or MES)Standard 120 V lamps7004-21A-2
E2727 mm[Medium] Edison Screw (ES)Standard 230 V lamps7004-21
E2929 mm[Admedium] Edison Screw (ES)
E3939 mmSingle-contact (Mogul- in America) Goliath Edison Screw (GES)120 V 250+ W industrial7004-24-A1
E4040 mm(Mogul) Goliath Edison Screw (GES)230 V 250+ W industrial7004-24
Source: Wikipedia: Edison Screw 5-31-2017

California requires remodels and new construction use a GU24 (bi-pin) socket. These types of sockets require matching bulbs and maybe limited to CFL or LED bulbs. Traditional sockets can be adapted to GU24 sockets with a simple adapter.

48707 - Medium Base E26 Socket to GU-24 Socket Adapter

Some Standards Don't Apply

As always, there are some exceptions to the rule. One exception might be a failed swivel on an old lamp. No matter how hard you try, the replacement piece does not exist. This is true, but swivels, arms, bodies, and bases are decorative features and not electrical parts. The standards for these parts are part of the thread sizes. A different topic.

Another complaint might be related to a European fixture. Maybe it has bayonet sockets or a strange size thread socket. Standards are still in play but are subject to regional preferences. Some older European fixtures have E17 Intermediate sockets. If you are in the process of a repair for a US market, convert the sockets to E12 Candelabra since these bulbs are easier to find.

47624 - Single Contact Brass Bayonet Socket With 1/8IPS Male Thread


This article only scratches the surface of bulb and socket standards. We didn't touch Wattage, the measurement of energy consumption for bulbs. We also didn't cover specialty antique style or decorative bulbs shapes and styles. 

What you can do with this new found knowledge? We suggest using it for light conversation at your next dinner party. 

Thursday, May 11, 2017

How To Install Lamp Plug On PVC Cord

Covered lamp cord comes in a variety of colors and styles. Some styles include parallel, twisted, and PVC and can be covered in rayon or cotton and dyed in a variety of colors.

Cotton Covered Parallel Lamp Cord
Unlike cord sets with a molded plug, these lamp cords need a plug attached to them. Different plugs sometimes have a special purpose like this plug designed for PVC cords.

48557BK - Black Plug for PVC Lamp Cords
Attaching a plug to a covered cord uses the same technique. In this example we are demonstrating a covered PVC cord to a plug designed for PVC cord.  First you slide the plug shell on the cord. Then you will need to strip back the cotton or rayon covering.

For PVC wires you will need to strip back the plastic jacket. For twisted and parallel, skip to the next step.

With the individual wires split and stripped down to the insulation, strip about 1/2 inch off the end.

Twist the bare wires so they will easily wrap around the screw posts of the plug. Wrap bare wires around screw post in a clockwise direction and tighten screws. If your plug is polarized, the black wire or smooth wire connects to the brass screw that corresponds to the slimmer post. The white wire or ribbed wire connects to the nickel screw that corresponds to the broad post.

Pull the plug shell up the cord and snap it on the plug interior. Other models might have an insulator or cap to place on the plug.


Friday, April 28, 2017

Making a Lamp from a Globe

A customer brought in a globe the other day and wanted to make it into a lamp. With the right lamp parts, anything is possible.

Our parts list includes:

4 feet of black PVC cord:
46617C - Black PVC 2 wire Medium Duty Cord

47684 - Turn-Knob On/Off Phenolic Socket
2 Inch Threaded Rod:
22350 - 2" Long, 1/8 IP Steel Nipple
Some lock nuts:
22702 - Plated Steel Lock Washers, 1/8 IP slip
Regular Washers:
22721 - 1" Regular Duty Steel Washer, 1/8 IP slip
11778BK - Satin Black Modern Shallow Canopy Kit
26922 - Black Cord Grip Bushing
26920 - Off-White Pulley Lamp Cord Bushing
Black Bushing Cap
26901 - Black Bakelite (plastic) Cord Bushing, Tap 1/8F

Now we are ready to get started. First, we want to remove the globe hardware.

Using a utility knife we cut along the 45th parallel south.

Then we clean up the edge with some light sandpaper. 

Using the hole where the hardware connected to the North Pole we place the threaded rod and reinforce it with some washers. The black bushing cap goes on the top of the rod. 

Next, we thread in the cord. It goes through the rod and through the socket cap. The socket cap threads on the rod. 

The PVC exterior is stripped back to expose the two internal wires. A UL knot is tied in the wires. The wires are stripped and attached to the socket interior. For polarity the black wire attaches to the brass screw and the white wire connects to the nickel screw. 

The cord slack is pulled from the top of the globe and the socket interior sits inside the socket cap. The phenolic shell screws on top of the socket interior.

Next, we work on the canopy. We didn't want to lose Antarctica, so it will be a canopy cover. First, we need to push the cord through our pulley bushing and then the hole in the cut off globe piece. 

Next, the cord is threaded through the canopy loop and then the hole in the center of the canopy. Since the PVC wire is reinforced we will not use a chain but will secure the cord at the top of the canopy with a grip bushing. 

Next, we connect the rest of the canopy kit to the canopy. 

This is a whole new world! Total Cost <$15.00 Total Time < 1 hour