Tool Detail
Vintage Starrett No. 492 Protractor Square
12 Inch Steel Rule – Antique Machinist Woodworking Tool
Vintage L.S. Starrett No. 492 adjustable protractor square, manufactured in Athol, Massachusetts. Features a cast-metal head, engraved dual-reading 180-degree protractor scale, 12-inch steel rule, and integrated spirit level. Cleaned and preserved with its original black finish, age-related patina, and historical markings intact. Both adjustment mechanisms operate, and the spirit level remains functional.
Detailed Description
A fine example of American precision toolmaking, this vintage L.S. Starrett No. 492 protractor square combines an adjustable angle-measuring head, a 12-inch graduated steel rule, and an integrated spirit level. Manufactured by the L.S. Starrett Company in Athol, Massachusetts, this versatile measuring instrument was designed for machinists, patternmakers, woodworkers, and other skilled tradespeople requiring adjustable angle measurements and layout capabilities. The protractor head features finely engraved, dual-reading angular graduations and a substantial cast-metal body with its original black finish.
Tool Details
- Manufacturer: L.S. Starrett Company
- Model: No. 492
- Origin: Athol, Massachusetts, USA
- Type: Adjustable protractor square
- Rule Length: 12 inches
- Rule Markings: No. 23 and No. 4
- Protractor: Dual-reading, 180-degree graduated scale
- Construction: Cast-metal head with steel rule
- Finish: Original black finish with exposed machined metal surfaces
- Spirit Level: Original integrated bubble level, functional
- Adjustments: Rotating protractor head and sliding steel rule
- Markings: Original manufacturer and model stamps
Condition
This instrument is in good restored vintage condition, exhibiting authentic wear consistent with its age and working history.
- Original black finish retained, with visible wear and areas of finish loss.
- Steel rule displays dark staining, scattered pitting, and evidence of previous surface corrosion.
- Engraved graduations remain visible, although some areas exhibit staining.
- Manufacturer markings on the head and rule remain legible.
- Protractor rotates and locks in position.
- Steel rule slides smoothly.
- Original spirit level remains functional.
- Previous owner’s identification marking remains on the casting.
- Precision accuracy has not been independently calibrated or certified.
The instrument has not been refinished or polished to a modern appearance. Its original surfaces and working character have been intentionally preserved. Please review all photographs for details of its condition.
Restoration
This tool has been carefully cleaned and preserved by Moab Maverick Tools.
Restoration included:
- Removal of accumulated dirt and surface oxidation.
- Cleaning of the steel rule and engraved graduations.
- Cleaning and preservation of the cast-metal protractor head.
- Preservation of surviving original finish and manufacturer markings.
- Inspection and lubrication of adjustment mechanisms.
- Application of protective oil and wax to exposed metal surfaces.
- Functional inspection of the sliding rule, rotating head, locking mechanisms, and spirit level.
Our restoration philosophy is simple: Preserve the Patina. The objective is to return vintage tools to clean, stable, functional condition without erasing the evidence of their history.
Ideal For
- Traditional woodworking and layout work
- Machinist and patternmaking tool collections
- Vintage Starrett tool collectors
- Antique measuring instrument displays
- Historical woodworking shops
- Industrial and workshop decor
- Gifts for woodworkers, machinists, and tool enthusiasts
Although mechanically functional, this vintage instrument has not been certified for precision measurement applications.
Highlights
- Genuine vintage L.S. Starrett instrument
- Desirable No. 492 adjustable protractor square
- Made in Athol, Massachusetts, USA
- Original 12-inch graduated steel rule
- Dual-reading 180-degree protractor scale
- Functional integrated spirit level
- Adjustable, locking protractor head
- Sliding and locking steel rule
- Original manufacturer markings
- Original black finish and authentic patina
- Cleaned, preserved, and mechanically inspected
- Printed vintage tool care guide included