Availability of the Ram Penetrometer (Haefeli Rammsonde) in the United States

During the winter of 1961-62 several people expressed an interest in obtaining a penetrometer for use at various points in the Western United States. In making inquiries it was found that very few work prints were available. Work prints that were available were in the metric system and most of the machine shops contacted in this area were reluctant to attempt to construct a penetrometer by using the metric prints. In an attempt to make the construction of a penetrometer easier and more compatible to our machine shops, a Denver firm was commissioned to make three penetrometers and at the same time make new work drawings converting, wherever possible, all metric figures to the English system.