1928 Milwaukee newspaper advertisement reading,
On February 20, 1928, 147 thousand, six hundred Master Padlocks were shipped by rail to New York City. The shipment weighed sixteen tons and was worth $65,000.  The humorous and ironical part was that the locks were made in Milwaukee, the national beer capital, and in quarters leased from the Pabst Brewery. Pabst was not brewing beer because of the National Prohibition Act. 

Five Flapper Women in fur coats posing in front of Master Lock Company rail shipment. February 1928.
The newspapers were full of articles concerning raids by Federal agents on distilling operations and speakeasies. The tools in the trade of the Federal agents consisted of two items; a long handled ax to smash the barrels of illegal brew and a supply of padlocks to secure the doors and prevent any further use of the establishment.

In the majority of cases, the locks used were Master padlocks, the strongest padlocks ever built. Twenty cold-rolled steel plates, seven times riveted and forming a solid, indestructible case. It could be hammered upon and would not break or crack.

It took seven trucks to move the 16 tons of locks from the company to the train yard. On the sides of the trucks were banners that read, "The Beer That Made Milwaukee Famous." These banners were crossed out and covered by banners, "Make Milwaukee Mightier." Acting Mayor Cornelius Corcoran of Milwaukee locked the rail car witha 3-foot padlock and broke a bottle of near beer over it. He sent the key to Jimmy Walker, mayor of New York, by air mail.
Images and research by John Lupiezowieck, Master Lock historian

Exhibit of Master Lock on display at the Chudnow Museum of Yesteryear since June 2016 - now