Removing Broken Screws

From American Horologist magazine, March, 1945

Removing Broken Screws 
(Contest Article No. 26)

To remove a broken steel screw from an alloy plate or bridge of a watch:

First, remove all steel parts that you do not wish destroyed.

Second, make a solution of Alum (Amonium Sulphate) and water - l part Alum to 3 parts water by volume. Bring the mixture to a boil in a glass vessel so the Alum will go into solution.

Third, drop the alloy part with the steel screw to be removed into the boiling solution. The steel will be dissolved in three to fifteen minutes, depending on the size of the part to be dissolved. As the boiling continues, replace the evaporated water.

Fourth, boil the part just removed from the solution in some fresh water to remove any crystaline Alum that may have formed on the part.

The conceptration of Alum is not critical, and not the slightest damage has ever been experienced as a result of using this very expedient method.