Jean Maritz also Johan Maritz, was a Swiss inventor, born in Burgdorf, Canton of Bern, who moved to France, becoming "Commissaire des Fontes" at Strasbourg

Strasbourg

Strasbourg is the capital and principal city of the Alsace region in eastern France and is the official seat of the European Parliament. Located close to the border with Germany, it is the capital of the Bas-Rhin département. The city and the region of Alsace are historically German-speaking,...

 (Commissionner of the King's Foundry), and invented the vertical drilling machine, as well as the horizontal drilling machine for cannons in the 18th century. His inventions revolutionized cannon-making, and became a key component of the de Vallière system, and contributed to the development of the later Gribeauval system

Gribeauval system

The Gribeauval system was an artillery system introduced by Lieutenant General Jean Baptiste Vaquette de Gribeauval during the 18th century. This system revolutionized French cannon, with a new production system that allowed lighter, more uniform guns without sacrificing range. The Gribeauval...

.

Jean Maritz first invented a vertical drilling machine for cannons while in France in 1713. The vertical drilling method however, in which a cannon was slowly lowered over a turning drill, was very delicate, very time consuming and rather imprecise.

He further developed a method for the horizontal drilling of cannons around 1734. These methods involved the drilling of a bore

Gauge (bore diameter)

The gauge of a firearm is a unit of measurement used to express the diameter of the barrel. Gauge is determined from the weight of a solid sphere of lead that will fit the bore of the firearm, and is expressed as the multiplicative inverse of the sphere's weight as a fraction of a pound . Thus...

 from a solid casting.

These inventions were vast improvements over previous methods, which involved founding the cannon around a clay core, which was removed after founding, leading to imprecision and shifting of the core, and therefore poor performance.

The inventions of Jean Maritz gave perfectly straight bores which could perfectly fit the ball diameter, and therefore vastly increase efficiency. In the horizontal method developed by Maritz, the solid-cast cannon itself was revolved horizontally, while the drill remained static, in a method similar to that of a lathe

Lathe

A lathe is a machine tool which rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.Lathes are used in woodturning,...

.

The son of Jean Maritz, bearing the same name as his father, and who had worked with his father on the development of boring, became Inspector General of Gun Foundries in 1755.

The Maritz method would be central in the development of the Gribeauval cannon.