Fred Locke's Attic (page 6)
This photo shows a lot of the multipart Fred Locke insulators that will be assigned new M-numbers soon. Those styles are shown with corresponding porcelain and glass bases. It is uncertain which base was used with the top; however, the one on the top left (second from left) was shown in old trade journals with that same white porcelain base.
U-4's
Similar to U-3
Tall unglazed porcelain bases. The one on the left is 8" tall and the one on the right is 5-1/2" tall. All have 1" threaded pinholes.
The one on the left is 4-1/4" tall; center is 3"; right is 3-3/4".
Porcelain bases are the same as those shown in the previous photo.
The various bases shown above were cemented in the insulator using sulfur. The glass Brookfield pony (far left) was ground down to fit in the porcelain insulator. The Brookfield glass base with embossed "B" on the far right was used, too, for M-2336.
This M-2336 is in my collection. It was found at the Victor factory. The exact insulator with the crown cut off was shown in a 1940 trade journal advertisement. The marking is #4-1 and is dated: APR. 10 190?