A holdfast or hold fast is a form of temporary
clamp used to hold a workpiece firmly to the top or side of a
wooden workbench or the top of an
anvil
An anvil is a metalworking tool consisting of a large block of metal (usually Forging, forged or Steel casting, cast steel), with a flattened top surface, upon which another object is struck (or "worked").
Anvils are massive because the hi ...
.
A form of
bench dog, a traditional holdfast has either a curved or flat top. Its shank is slid loosely into a “dog” hole in the bench or anvil until the tip of its hook touches the work. It is set by hitting its top with a
mallet
A mallet is a tool used for imparting force on another object, often made of rubber or sometimes wood, that is smaller than a maul or beetle, and usually has a relatively large head.
General overview
The term is descriptive of the ...
or
hammer
A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nail (fastener), nails into wood, to sh ...
, which causes the shaft to wedge tightly against the sides of the hole. A tap of its back side near the top releases it.
Contemporary holdfasts are commonly designed to fit in holes, somewhat narrower than had been traditional. Scrap pieces of wood or leather are often used between the holdfast and the workpiece to prevent marring it.
An adaptation of the holdfast is threaded, sometimes known as a “screwdown”, which is tightened rather than tapped in place.
History
Based on a fresco discovered in the ruins of
Herculaneum
Herculaneum is an ancient Rome, ancient Roman town located in the modern-day ''comune'' of Ercolano, Campania, Italy. Herculaneum was buried under a massive pyroclastic flow in the eruption of Mount Vesuvius in 79 AD.
Like the nearby city of ...
, holdfasts are known to have been in use since at least the 1st century AD. They are also described and illustrated in early European books on woodworking, such as
Joseph Moxon's 1678 edition of ''Mechanick Exercises'' and
André Jacob Roubo's 1774 ''L'Art du Menuisier.'' The term has been in use since at least the 16th Century. Use declined throughout the 20th century, but has seen a resurgence in recent years.
While "artisan" holdfasts continue to be made as castings, or forgings, modern holdfasts are made from round mild steel bar stock using highly automated cold-working machines. Gramercy Tools makes such holdfasts from bar stock which is slightly under 3/4" (19.05mm) dia., usually 19mm for use in the now customary 3/4" bench holdfast holes. The making of such a holdfast is more particularly described in Gramercy Tools' patent document (U.S. Patent 7,571,631, to Moskowitz, et. al.).
Gallery
File:Holdfast illustration adapted from L'Art du Menuisier.png, Illustration from L'Art du Menuisier (1769) demonstrating how the holdfast is secured in the workbench hole
File:Engraving showing two putti using a Roman workbench, based on a fresco from the ruins of Herculaneum.jpg, Roman workbench with a holdfast, based on a 1st Century AD fresco from the ruins of Herculaneum
File:Cc&j-fig40--bench holdfast.png, Illustration of a screwed holdfast from ''Cassell's Carpentry and Joinery'' (1907)
File:Men veneering from L'Art Du Menuisier-Carrossier (Roubo).png, Illustration from L'Art du Menuisier (1769) showing a workbench with holdfasts in use
See also
*
Bench dog
*
Clamp (tool)
A clamp is a fastener, fastening device used to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure. In the United Kingdom the term cramp is often used instead when the tool is fo ...
References
{{DEFAULTSORT:Hold Fast
Woodworking clamps