Engineering:Holdfast (tool)
 A carpenter using a holdfast | |
| Other names | Hold fast, hold-down |
|---|---|
| Used with | Woodworking workbench or anvil |
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]
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
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See also
References
- ↑ Bealer, Alex (1989). Old Ways of Working Wood: The Techniques and Tools of a Time-Honored Craft. New York: Bonanza Books. p. 73. ISBN 0-517-69313-5. https://archive.org/details/oldwaysofworking00beal/page/73.
- ↑ "Why a 1" Holdfast Hole?" (in en-US). 2019-04-03. https://blog.lostartpress.com/why-a-1-holdfast-hole/.
- ↑ The Complete woodworker. Jones, Bernard E. (Bernard Edward), 1879-1965. (New ed.). Berkeley, Calif.: Ten Speed Press. 1980. pp. 50–52. ISBN 0-89815-022-1. OCLC 7283260.
- ↑ Schwarz, Christopher (2018). Ingenious Mechanicks: Early Workbenches & Workholding. Fort Mitchell, Kentucky: Lost Art Press LLC. pp. 4–8, 100–110. ISBN 978-0-9978702-7-5. https://lostartpress.com/collections/books/products/ingenious-mechanicks.
- ↑ Moxon, Joseph (April 1678). "The Art of Joynery". Mechanick exercises, or, The doctrine of handy-works : began Jan. 1, 1677 and intended to be monthly continued. Boston Public Library. London: Joseph Moxon, at the sign of the Atlas on Ludgate Hill. pp. 56–61. https://archive.org/details/mechanickexercis00moxo.
- ↑ Roubo, M. André Jacob (1769). L'art du menuisier. Getty Research Institute. Paris: Académie Royale des Sciences. pp. 32–35. https://archive.org/details/gri_33125009321916.
- ↑ "How do You Say 'Holdfast?'" (in en-US). 2014-03-02. https://blog.lostartpress.com/2014/03/01/how-do-you-say-holdfast/.
- ↑ "Holdfasts - How To Make Them Grip Like A Gorilla" (in en-GB). 2013-05-28. https://www.theenglishwoodworker.com/holdfasts-get-a-grip/.
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