turn of the screw: The history of Stanley screwdrivers, The

Screwdrivers, earlier known as turnscrews, have been around since at least the fifteenth century. At first, screwdrivers were very scarce because screws were so expensive to manufacture. But the beginning of the nineteenth century saw the arrival of machine-manufactured screws. As the per-piece cost of screws came down, their use increased, and with that, the need for more screwdrivers.

Until the 1840s, screws had a flat or blunt tip, which necessitated drilling a lead hole first in order to start the screw. Early screws had their heads slotted by hammering a knife-edge into a red-hot screw head.

The screwdriver was flat and the tip was ground or beveled on both sides almost to a point to fit the V-- slot. When the first machine-made screws came out, their heads were slotted with a saw.

Finally, machinery was developed to make the screws with a gimlet point. Then the price of the screws came down and the practicality of their use improved, especially with the use of butt hinges.

With advances in screw manufacturing, more screwdrivers began to appear. Up until the 1850s, screwdrivers had a flat blade with a turned handle that was flat on two sides. These common flat blade screwdrivers were made into two patterns-the London pattern and the Scotch pattern-that evolved over time (Figure 1). The London pattern had a semi-circular dip on the sides, about halfway down the blade. The Scotch pattern was a straight, tapered blade.

It wasn't until 1870 that Stanley entered into the screwdriver business. Up until then, there were only fifteen United States screwdriver patents. The earliest known United States patent was issued in 1852. The patent dealt with a screwdriver attachment to a brace. All the others, with two exceptions, were concerned with either leverage attachments or early spiral screwdriver designs, and had nothing to do with improving the basic, centuries-old design.

On 23 July 1867, J. A. Ayres of Hartford, Connecticut, patented an improved screwdriver (Figure 2). His patent dealt with improving the tip by cutting a dovetail cross section on the end. When the screwdriver was used, it bit into the slot, reducing slip out. This idea, of course, didn't last because the tip of the screwdriver broke at the dovetail.

The other patent, by J P. Curtiss, was for an improvement in screwdrivers by securing the shank in a solid handle (Figure 3). The blade was cut out by means of the usual die and punch. The tang, or shank, that went into the solid handle was notched and recessed on each side. A hole was drilled in the center of the handle, wider than the notched shank, but not all the way through. The shank was then driven into the end and molten lead and antimony were poured into the hole on the side, thus securing the metal part of the screwdriver. The resulting accumulation of metal was then shaved off to finish the screwdriver. Figure 4 shows an early Stanley screwdriver with a Curtiss patent and a flat handle.

Stanley cast steel screwdrivers, with the Curtiss patent, started showing up in its 1870 catalog. It is unclear whether Curtiss was employed by Stanley or whether the company secured his patent. In any event, the fact that his design appeared in Stanley catalogs before the patent was issued, suggests Curtiss was employed by Stanley.

The design of this screwdriver was the London pattern. It was first made with wrought iron ferrules (patented by S. N. Chapin), but by the end of 1870, it was changed to a brass thimble or ferrule (Figure 5).

These screwdrivers were initially offered in sizes two through ten inches and twelve-inch lengths. By 1871, a one and one-half inch length had been added to the line, and flat or oval handles for each size were offered.

An 1872 Stanley advertisement noted: "By the aid of improved machinery we are now producing a screwdriver which is superior to any other in the market-- and at the prices paid for the ordinary tools."

By 1874, Stanley was offering its screwdrivers in no. 1 grade with Curtiss's metallic fastening and in no. 2 grade without the metallic fastening at a discount price. Oval handles were discontinued at this time (Figure 6).

Shortly afterward, around 1876, the no. 1 was sold with black enameled handles only. In 1879 Stanley eliminated the no. 2 grade screwdriver and offered the no. 1 grade in varnished and black enameled handles (Figure 7).

Stanley, in 1888, finally began numbering its screwdrivers. No. 64 had a varnished handle and was a solid cast steel screwdriver with patent metallic fastening. The no. 75 is the same screwdriver but had black enameled handles. Both the no. 64 and no. 75 are the London patterns. Another screwdriver, no. 86, was introduced with polished handles and no metallic fastening. It did not have Curtiss's patent. This screwdriver had the Scotch pattern blade.

The no. 75 screwdriver, with black enameled handle, was discontinued in 1892. Only the no. 64 with varnished handle and the no. 86 in the Scotch pattern remained in the catalogs. The no. 64 screwdriver was changed to a Scotch pattern in 1919. Both the no. 64 and no. 86 were discontinued in 1927 (Figure 8, front cover deg).

Walter Jacob writes a regular column on Stanley tools for The Chronicle. His next article in this series will discuss George Wood's and John Hurley's contribution to the screwdriver business.

Copyright Early American Industries Association Mar 2002
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