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The Encyclopedia of Horology

Tool · Jacot tool

Watchmaker's jacot tool

Partially verified

This object is a specialised watch- and clockmaker's jacot lathe used for burnishing pivots, held in the Science Museum Group collection under object number 1960-218. According to the source, the pivot projects through a small hole in the plate on the end of the runner, allowing a burnishing tool to be applied while the component is rapidly rotated via a bow. The tool comprises a horizontal metal frame with adjustable runners and knurled clamp screws, photographed mounted on a clear display plinth alongside a detached interchangeable runner.

Full view of the jacot tool supported on an acrylic block labelled 1960-218 with an extra runner
Full view of the jacot tool supported on an acrylic block labelled 1960-218 with an extra runner — The Board of Trustees of the Science Museum. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
collection.sciencemuseumgroup.org.uk
Category
Tool · Jacot tool
Maker / attribution
Not established
Reference
1960-218
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
Not established
Country
Not established

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Identity and Functional Description

Catalogued under object number 1960-218 in the Science Museum Group collection, this instrument is recorded under the title "Watchmaker's jacot tool" and described as a "specialised watch and clockmaker's lathe for burnishing pivots." It is classified under the museum category "Hand and Machine Tools" and assigned the credit "Freeman, A."

The operation of the lathe is summarized in the catalog description: "The pivot projects through a small hole in the plate on the end of the runner and the burnishing tool is applied to the pivot while the latter is rapidly rotated by means of the bow."

Evidence for this section
  • “Watchmaker's jacot tool”
  • “This is a specialised watch and clockmaker's lathe for burnishing pivots.”
  • “Category: Hand and Machine Tools”
  • “credit: Freeman, A.”
  • “The pivot projects through a small hole in the plate on the end of the runner and the burnishing tool is applied to the pivot while the latter is rapidly rotated by means of the bow.”

Observed Construction and Accessories

In the photographed assembly, the tool is mounted with a small toothed watch wheel positioned between the tool centers. Two prominent knurled vertical clamp screws are visible atop the frame pillars.

A separate metal runner accessory is visible lying to the right on the reflective surface. The entire setup is displayed resting upon a clear acrylic plinth labelled with inventory number 1960-218.

Evidence for this section
  • “A small toothed watch wheel mounted between the tool centers”
  • “Two prominent knurled vertical clamp screws atop the frame pillars”
  • “Separate metal runner accessory lying to the right on the reflective surface”
  • “Clear acrylic plinth labelled with inventory number 1960-218”

Source Documentation and Omissions

The museum record specifies "type: tool" but does not record the maker, date of production, or country of origin in its catalog fields.

While the functional description mentions rotating components by means of a bow and applying a burnishing tool, neither a bow nor a burnisher is recorded in the accession details or visible in the accompanying photograph.

Evidence for this section
  • “type: tool”
  • “The pivot projects through a small hole in the plate on the end of the runner and the burnishing tool is applied to the pivot while the latter is rapidly rotated by means of the bow.”

Open research questions

  • Does the physical object bear any maker stamps, hallmarks, or serial numbers that are not documented in the online catalogue?
  • What specific role is represented by the credit line 'Freeman, A.' (such as donor, vendor, or previous owner)?
  • Were accessories like a driving bow or pivot burnishers originally collected under accession 1960-218?

Source evidence

Recorded claims and source quotations for Watchmaker's jacot tool
FieldSource-reported valueSource quotation
Object Number1960-218“Object Number: 1960-218”
FunctionSpecialised watch and clockmaker's lathe for burnishing pivots“This is a specialised watch and clockmaker's lathe for burnishing pivots.”
CategoryHand and Machine Tools“Category: Hand and Machine Tools”
CreditFreeman, A.“credit: Freeman, A.”
Typetool“type: tool”
Object TitleWatchmaker's jacot tool“Watchmaker's jacot tool”

Visible details

  • A small toothed watch wheel mounted between the tool centers
  • Two prominent knurled vertical clamp screws atop the frame pillars
  • Separate metal runner accessory lying to the right on the reflective surface
  • Clear acrylic plinth labelled with inventory number 1960-218

Research qualifications

  • The source does not record the manufacturer, country, or date of production
  • Accompanying bow and burnisher are not shown with the tool

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Watchmaker's jacot tool | Science Museum Group Collection

Reviewed 2026-10-21 · Record dceaae6c17

Terms in this record

Glossary explanations for terms named in this object’s record.