Holdfast (tool)

For other uses, see Holdfast (disambiguation).

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.^[1]

Holdfast

A carpenter using a holdfast
Other names	Hold fast, hold-down
Used with	Woodworking workbench or anvil

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 or hammer, 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 3⁄4 inch (19 mm) holes, somewhat narrower than had been traditional.^[2] 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.^[3]

History

Based on a fresco discovered in the ruins of Herculaneum, holdfasts are known to have been in use since at least the 1st century AD.^[4] 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.^[5][6] The term has been in use since at least the 16th Century.^[7] Use declined throughout the 20th century, but has seen a resurgence in recent years.^[8]

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

• 
  Illustration from L'Art du Menuisier (1769) demonstrating how the holdfast is secured in the workbench hole
• 
  Roman workbench with a holdfast, based on a 1st Century AD fresco from the ruins of Herculaneum
• 
  Illustration of a screwed holdfast from Cassell's Carpentry and Joinery (1907)
• 
  Illustration from L'Art du Menuisier (1769) showing a workbench with holdfasts in use

See also

• Bench dog
• Clamp (tool)