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Details on hand drilling natural stone

The following hand drills were distinguished:

Churn or ball drill (hand drilling without hammer, vertical holes) [1].
Plug drill / Hammer drill / Jumper drill (hand drilling with hammer, holes in all directions) [1].

The "churn drill" (l = 7ft / approx. 2.1m) was lifted and then dropped. An additional weight, usually in the form of a metal ball, was placed in the middle of the drill rod to reinforce the blow. For deep holes (> 90cm), the churn drill was operated by several people. For vertical holes, the churn drill was the most effective drilling method [2].

 The "hammer-drill" with a simple cutting edge or with a star-shaped cutting edge (star-drill), was used by hitting the drill with a hammer. In this way, it was possible to drill not only vertically, but also horizontally and upwards.

Drilling capacity "one-man"
2.6 ft / h. (5/8 inch diameter) = 78 cm/h [1].
60 - 80 ponciotto holes per day [1].
8 inch/h = approx. 20 cm (rock of medium hardness) [3].

Bohrleistung "zweimännisch" (1,5 inch Durchmesser):
Granit: ca. 0.7ft / h. = 21cm / h [1].
Basalt: ca. 1.1ft / h. = 33 cm / h [1].
Kalk: ca. 16 ft / h. = 48 cm / h [1].
2 feet/h = ca. 60cm (Gestein mittlerer Härte) [3].

When drilling holes deeper than 60cm, several drills were used whose diameter decreased with increasing hole depth. Such a "drill set" consisted of a beginner, middle and end drill. The art of hand drilling consisted in always guiding the drill exactly on the axis [4].

Quellen:

  1. Handbook of rock excavation, methods and costs, Halbert Powers Gillette, London, Hill Publishing Co., 1916
  2. Brunner & Lay, Manufacturers of Marble, Stone, Granite and Bricklayers’ Tools, Stone Jacks, Derricks, and Contractors’ Supplies (http://quarriesandbeyond.org/articles_and_books/stone_magazine/brunne_an...)
  3. The rock drill and civilization, Larry C. Hoffman, Invention & technology magazine, vol. 15, issue 6, 1999
  4. Die Bauweise mit Naturstein, Adolf Stoller, 1949