by John Wells

The Stanley No. 239 Special Dado Plane was covered by Christian Bodmer's March 30, 1915 Patent No. 1,134,072. It was assigned The No. 239 First Model to the Stanley Rule and Level Co. The patent drawing illustrated the plane exactly as it was offered in the 1915 Stanley No. 34 Catalogue.

(Webmaster's note: This article was scanned from the Winter 1997 edition of ToolTalk)



The Ideal Tool

Stanley described the No. 139 as being an ideal tool for blind wire grooving and therefore of special interest to electricians. Blind wiring was a term used to describe the practice of installing electrical wires in a pair of narrow grooves cut in a surface-applied wood molding covered with a thin wood cap. In the teens and early twenties, blind wiring was a popular method for installing electric wiring and lighting in existing homes that were originally illuminated by gas lights.


The 239 and how it worked

  • A narrow 1/8 inch wide plow cutter projected through a thin deep skate that allowed cutting grooves up to 1/2 inch deep.
  • A depth stop controlled the depth of cut and a vertical double spur cutter in front of the plow cutter was sharpened to score the fibers of the wood on each side of the cut when plowing grooves across the grain.
  • The plane had a forward tilted iron handle and a circular ring for the index finger. This made the plane easy to use and allowed it to be controlled with one hand.

The 1915 Catalogue listed the No. 239 Special Dado Plane in the same group with the No. 39 series of Iron Dado Planes.

  • The 1/8 inch wide cutter of the No. 239 extended the choice of dado widths provided by Stanley Iron Dado Planes to range from 1/8 inch to 1 inch by 1/8 inch increments.
  • The early version of the No. 239 (like all the other planes in the No. 39 series of Iron Dado Planes) did not have a fence.
In 1919, Stanley offered a second version of the Special Dado Plane. It was called the No. 239 1/2 Improved Dado Plane.

The 239 1/2 and how it worked

  • The No. 239 1/2 was intended primarily for plowing grooves parallel to the grain.
  • It had a fence the same length as the skate which made it convenient to use for plowing grooves parallel to the long edge of a wood molding.
  • Since the plane was not intended for cross grain work, the casting was not machined to accommodate the vertical double spur cutter.
  • It was interesting that Stanley Catalogues of the period did not illustrate or describe the No. 239 1/2 as being without the double spur cutter for cross grain work.

A Description of the 239 1/2

  • The body casting was not milled out to receive the vertical double spur cutter.
  • A long fence was mounted on a pair of arms identical to those used on the No. 78 Rabbit Plane.
  • The Box Label had a small supplemental label imprinted "1/2" pasted at the end of "No. 239".
  • The No. 239 1/2 was offered for only four years ( 1919 to 1923) which accounts for it's relative scarcity.

The End of the 239 1/2

The No. 239 1/2 was dropped from the line in 1923. Existing stock was probably sold by the time the fence was added to the No. 239.

The 239 Addition

In 1925, a fence was added to the No. 239.

  • The fence adapted the 239 for cutting grooves both parallel to and across the grain.
  • This change made it unnecessary for workmen to carry two similar planes and saved retailers the expense of stocking both of them.

In 1926 and later, the No. 239 was offered in 1/8 inch, 3/16 inch or 1/4 inch widths. In 1929, the option of a 5/32 inch width was added and the 1/4 inch width was discontinued.

Experimental Models of the 239

An experimental model of the No. 239 is illustrated in figure 385 on page 243 of Patented Transitional and Metallic Planes in America, Volume II by Roger K. Smith.

Another interesting experimental variation of the No. 239 is illustrated in the opposite photo and in the March 1995 issue of The Gristmill Magazine published by the Mid-West Tool Collectors Association. This variation plowed a 1/16 inch wide groove and had a small skew cutter mounted in an L-shaped bed at the top of the plane to provide a 90 degree trim function.

 -John Wells has been a member of PAST for many years. He and his wife, Janet sell tools under the name Grizzly Antiques (see back page ad). John and PAST member, Jack Schoellhamer have recently written a major two-part article for The Gristmill on "Bailey's Excelsior Block Plane ". The articles appear in the June and September 1996 issues.

 -For further information on PAST member Roger K. Smith's book, Patented Transitional and Metallic Planes in America. contact:

Roger K. Smith. Box 177. Athol, MA 01331