Skelp
Encyclopedia
Skelp is iron or steel rolled or forged into narrow strips and ready to be made into pipe
or tubing by being bent and welded. It is most commonly used in the traditional terminology of smithing
and in the iron
and steel
industries. Before the 20th century, the welding was likely to be forge welding
. In the 20th and 21st centuries, it has been likelier to be arc welding
or gas welding
.
In the context of traditional gunsmith
ing, one way to make gun barrel
s has been to make them from skelp, like one would make other pipe or tubing. Barrels made from skelp have typically been thought of as having inferior quality. (Pipe made from skelp can be perfectly acceptable in quality, but a gun barrel must withstand much higher pressures than most pipes.) Cheap gun barrels could be made this way in the Damascus method—wrapping the skelp around a mandrel
to make spiral
s which were then hammer
ed and forged into a tube. The mandrel was then removed, the interior reamed
, and the exterior filed
until a finished tube was complete. The tube was then polished
and breeched.
This method of fabrication
was used because it was difficult to cast
a solid barrel and then drill
it out without the bit
coming out the side. In many regions and eras, especially before the 20th century, gunsmithing has been achieved without the help of advanced machine tool
practice, such as gun drill
ing or advanced boring methods. In such contexts, advanced smithing and filing skills have often made up for the lack of machine tools.
Damascus barrels were generally designed for black powder
charges. The breech end of the tube was much thicker than the muzzle
end, and this held the initial impulse pressure from the black powder. By the time the bullet
reached the muzzle, the pressure had dropped quite a bit, so muzzle reinforcement wasn't needed. This gave a better weight distribution through the length of the weapon.
Smokeless powder
s burn more slowly than black powder, thus maintaining high pressures throughout the barrel. Since the barrel is not reinforced at the muzzle, it may not be able to contain the pressure. Also, most Damascus barrels were made before modern smokeless powders, so the age of the barrel can be a safety hazard.
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...
or tubing by being bent and welded. It is most commonly used in the traditional terminology of smithing
Blacksmith
A blacksmith is a person who creates objects from wrought iron or steel by forging the metal; that is, by using tools to hammer, bend, and cut...
and in the iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
industries. Before the 20th century, the welding was likely to be forge welding
Forge welding
Forge welding is a solid-state welding process that joins two pieces of metal by heating them to a high temperature and then hammering them together. The process is one of the simplest methods of joining metals and has been used since ancient times. Forge welding is versatile, being able to join a...
. In the 20th and 21st centuries, it has been likelier to be arc welding
Arc welding
Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct or alternating current, and consumable or non-consumable electrodes...
or gas welding
Oxy-fuel welding and cutting
Oxy-fuel welding and oxy-fuel cutting are processes that use fuel gases and oxygen to weld and cut metals, respectively. French engineers Edmond Fouché and Charles Picard became the first to develop oxygen-acetylene welding in 1903...
.
In the context of traditional gunsmith
Gunsmith
A gunsmith is a person who repairs, modifies, designs, or builds firearms. This occupation is different from an armorer. The armorer primarily maintains weapons and limited repairs involving parts replacement and possibly work involving accurization...
ing, one way to make gun barrel
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
s has been to make them from skelp, like one would make other pipe or tubing. Barrels made from skelp have typically been thought of as having inferior quality. (Pipe made from skelp can be perfectly acceptable in quality, but a gun barrel must withstand much higher pressures than most pipes.) Cheap gun barrels could be made this way in the Damascus method—wrapping the skelp around a mandrel
Mandrel
A mandrel is one of the following:* an object used to shape machined work.* a tool component that grips or clamps materials to be machined.* a tool component that can be used to grip other moving tool components.- Variants :...
to make spiral
Spiral
In mathematics, a spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.-Spiral or helix:...
s which were then hammer
Hammer
A hammer is a tool meant to deliver an impact to an object. The most common uses are for driving nails, fitting parts, forging metal and breaking up objects. Hammers are often designed for a specific purpose, and vary widely in their shape and structure. The usual features are a handle and a head,...
ed and forged into a tube. The mandrel was then removed, the interior reamed
Reamer
A reamer is a metalworking tool used to create an accurate sized hole. The process is called reaming. They may be used as a hand tool or in a machine tool, such as a milling machine or drill press.-Construction:...
, and the exterior filed
File (tool)
A file is a metalworking and woodworking tool used to cut fine amounts of material from a workpiece. It most commonly refers to the hand tool style, which takes the form of a steel bar with a case hardened surface and a series of sharp, parallel teeth. Most files have a narrow, pointed tang at one...
until a finished tube was complete. The tube was then polished
Polishing
Polishing is the process of creating a smooth and shiny surface by rubbing it or using a chemical action, leaving a surface with a significant specular reflection In some materials polishing is also able to reduce diffuse reflection to...
and breeched.
This method of fabrication
Fabrication (metal)
Fabrication as an industrial term refers to building metal structures by cutting, bending, and assembling. The cutting part of fabrication is via sawing, shearing, or chiseling ; torching with handheld torches ; and via CNC cutters...
was used because it was difficult to cast
Casting
In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process...
a solid barrel and then drill
Drill
A drill or drill motor is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of...
it out without the bit
Drill bit
Drill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes....
coming out the side. In many regions and eras, especially before the 20th century, gunsmithing has been achieved without the help of advanced machine tool
Machine tool
A machine tool is a machine, typically powered other than by human muscle , used to make manufactured parts in various ways that include cutting or certain other kinds of deformation...
practice, such as gun drill
Gun drill
Gun drills are straight fluted drills which allow cutting fluid to be injected through the drill's hollow body to the cutting face. They are used for deep drilling—a depth-to-diameter ratio of 300:1 or more is possible. Gun barrels are the obvious example; hence the name...
ing or advanced boring methods. In such contexts, advanced smithing and filing skills have often made up for the lack of machine tools.
Damascus barrels were generally designed for black powder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
charges. The breech end of the tube was much thicker than the muzzle
Muzzle (firearm)
The muzzle of a firearm is the end of the barrel from which the projectile will exit.Precise machining of the muzzle is crucial to accuracy, because it is the last point of contact between the barrel and the projectile...
end, and this held the initial impulse pressure from the black powder. By the time the bullet
Bullet
A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...
reached the muzzle, the pressure had dropped quite a bit, so muzzle reinforcement wasn't needed. This gave a better weight distribution through the length of the weapon.
Smokeless powder
Smokeless powder
Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder which they replaced...
s burn more slowly than black powder, thus maintaining high pressures throughout the barrel. Since the barrel is not reinforced at the muzzle, it may not be able to contain the pressure. Also, most Damascus barrels were made before modern smokeless powders, so the age of the barrel can be a safety hazard.