What Are
By Roger Russell
Copyright
1996-2005 by Roger Russell
All rights reserved
No portion of this site may be reproduced in whole or in part
without written permission of the author.
The main pieces of
many of the
The truth is that the retainer ring at the rear and the gear ring inside are made of steel. Once they are removed, the magnet is no longer attracted to the outer ring. There's more to the story, however, and there are other metals besides brass that are non- magnetic.
The Golden Hour and some other models are 24 karat gold plated. Here's an
ad from the
The main parts are not
made of brass. The base and frame are made of a less expensive alloy casting. A
cross section of this Golden Hour base shows the material to be silver colored.
I sent a sample of the base from a 1961 Golden Hour to a highly qualified
testing laboratory: Bodycote Taussig,
Inc., 7530 Frontage Road, Skokie, IL 60077. They identified the
metal as a common zinc alloy 3 per
INTERZINC refers to this as a traditional zinc alloy known as Zamak #3. It was originally developed in the 1930's and aluminum is the major alloying element at a nominal 4 percent. There's a small amount of magnesium and copper. Adding aluminum to zinc increases castability and results in finer grainsize castings and improved mechanical properties. Magnesium is added to improve strength and hardness and to protect castings from intergranular corrosion. Copper further strengthens and improves wear resistance of castings but at the expense of stability (dimensional and property), especially when copper content exceeds 1 percent.
|
Zinc Alloy Chemistry Zamak #3 |
Golden Hour Sample |
|
|
aluminum |
3.5 to 4.5% |
4.05% |
|
|
|
|
An interesting feature about the gold plating process is the need for first plating the zinc casting with nickel. This provides better adhesion for the gold plating. In addition, a bright nickel plate will give a high level of luster to the gold plated finish. If the gold finish is removed from the Golden Hour base and ring, the nickel finish will be exposed.
Of course, the problem occurs when owners think the clock is brass and go about trying to polish the clock with brass cleaner or even coarser material to bring the shine of the "brass" out. The thin gold plating is then inadvertently worn through and the finish is ruined. The only solution is to then have the base and ring replated.
The hand assembly is made of brass. The gold plated retaining ring, gear ring, three small leaf springs and, of course, the motor are made of steel.
A similar test made on a Haddon Golden Vision clock yielded similar information. The casting is also a zinc alloy, Zamak #3.
Two Different Base Castings Have Been Found
In a Golden Hour
dated
At the bottom of the base there is a ridge on the inside and several round bosses, one of which can be seen at the corner at the right. Similar castings have been found on earlier clocks and up as far as 1953.
The year 1953 appears to be a transition year where both <&> and M bases were used. The ridge did not appear on some M or <&> type bases and the boss height was greatly reduced. After 1953 or possibly a little later, no ridge or bosses have been found and only M type bases were apparently used.
In a Golden Hour
dated
This casting does not have the inner ridge or the bosses. The overall base casting appears to use less material than the earlier version and may have been a more economical requirement, considering the number of clocks that were being made.
The base casting part number and symbol can be found under the motor.
|
About This Site |
||
|
|
More text and pictures about |
|
|
Email to |
|
Created by Roger Russell |