Many people believe that the Allen Wrench clearly must have been invented by someone named Allen or with the surname Allen. Whether the Allen relationship exists all depends on whom you ask. There are two companies that both take credit for creating the Allen Wrench.
There is some discrepancy as to who it is invented the all too familiar Allen Wrench. Allen Wrenches also called Hex Keys were being patented under various names as far back as 1860 in the US however manufacturing of the patented wrenches never took place because of the associated expense with manufacturing in that time frame. In most cases the “inventor” had similar designs that were submitted for patenting.
The actual original design was rumored to come out of the UK but evidently was far too expensive for American tastes at the time so copycat inventors set out to replicate the design under American patent.
Yes There Is An Allen
There were literally 30 patents filed around the same timeframe in the United States, making it difficult to pinpoint whose was approved first. William G Allen of the Allen Manufacturing Company in Connecticut was the first to produce the Hex Key that would come to be most commonly known as an Allen wrench in 1910.
The “Allen Safety Set Screw” was the first of its kind although there are some accounts that would beg to differ. The founder of the Standard Pressed Steel Company claims that they were the first to manufacture the Hex Wrench under the Unbrako Line of tools. While the Unbrako Line is a very well-known line and in some places of the world a hex key is called an Unbrako wrench in the US the familiar Allen Wrench or Allen Key is used most when describing a hex key.
It is very likely that both manufacturers came out with these products at similar times but it would seem that since the Allen Manufacturing Company was most associated with this tool that it is very likely that they were the first ones to market with it. It may also be possible that the “Allen” name was just easier on the tongue than the Unbrako name. In any event the true “inventor” has been lost to history.