Project: Stone carving tools
A. Hammers and mallets
Mallets are the basic tool of every drystone mason. The weight of the hammer should not exceed 1 kg in order not to overload the tendons of the hand during longer work with the hammer.
Hammers and mallets should always be made of softer steel than the chisels they are hitting. It is not easy to find unhardened hammers today. However, commercially available steel hammers can be annealed to remove the hardening of the steel.
Whereas in the past a variety of different shaped mallets were used, today only standard shapes are available. Below are some examples of hammer shapes used in the past, which were adapted to the rock to be worked.
B. Tool handles
Below you see some historic handle shapes (the mallet handles were made as slip handles !).
There is still no material that can replace the classic wooden handles. In terms of durability and ergonomics (avoiding vibrations in the hand), wood is still the best material for handles. Today the handles are often machine made. They are often not worth much as they do not respect the natural course of the wood fibres.
Source img: "Gotthardbahn, Auszug aus den Vorschriften des Bedingnisheftes über die Ausführung des Mauerwerks", 1873
In the past, forged chisels were used. The tips of these chisels were shaped differently depending on the hardness of the rock to be worked.
Today, chisels with carbide inserts are mostly used. These have a much longer service life.
D. Verschiedene Meissel zur Steinbearbeitung
Keillochmeissel [cape chisel]. Dieser Meissel wurde für die Herstellung von rechteckigen Keillöchern verwendet. Mithilfe von Metallkeilen, welche in diese rechteckigen Löcherochlagen wurden, konnten die Steine gespalten werden.
Details on hand drilling natural stone
The following hand drills were distinguished:
Churn or ball drill (hand drilling without hammer, vertical holes) .
Plug drill / Hammer drill / Jumper drill (hand drilling with hammer, holes in all directions) .
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 .
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 .
60 - 80 ponciotto holes per day .
8 inch/h = approx. 20 cm (rock of medium hardness) .
- Handbook of rock excavation, methods and costs, Halbert Powers Gillette, London, Hill Publishing Co., 1916
- 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...)
The rock drill and civilization, Larry C. Hoffman, Invention & technology magazine, vol. 15, issue 6, 1999
Die Bauweise mit Naturstein, Adolf Stoller, 1949