Disston chainsaw history: dated facts from two United States patents and two museum catalogue records

This page reports what the official source says. It is not legal advice: ask the office named here. It sets a patent record and museum catalogue records side by side, and nothing here ranks one maker against another. The Swedish record is in Swedish: the wording here is our own summary of it.

Dated facts

Disston chainsaw facts in date order, with the page that dates each one
Date	What the source says
May 22, 1945 to October 25, 1949	The United States patent office printed patent 2,485,962, titled "Chain saw". It names John M. Entwisle of Philadelphia, Pennsylvania, as inventor, and Henry Disston and Sons, Inc., of Philadelphia, a Pennsylvania corporation, as the party he assigned it to. The application is dated May 22, 1945, serial number 595,083, and the patent was granted on October 25, 1949, with 4 claims. The text says the invention concerns chain saws, in particular the way the cutting chain is driven. One stated object is a cutting chain and drive sprocket assembly in which the first stable driving connection between sprocket and chain holds over long use, in spite of the chain growing longer as its parts wear. Another is that the links carrying the cutting teeth stay in the position in which they work best whatever the wear. Source: US patent 2,485,962.
1948 to 1949	A Swedish technical museum catalogues a chainsaw made by Henry Disston and Sons Inc in Philadelphia, United States, and dates it 1948 to 1949. The record calls it a chainsaw and says it has a Mercury motor of 3.5 horsepower, series number 281458. The record gives no weight or measures. Source: DigitaltMuseum record TEKS0034740.
Not dated	The Jack Morgan Museum lists, on the eHive catalogue, a Disston chainsaw as record 2010.2.292. The inscriptions it gives read "Kiekhaefer air cooled mercury full jewelled engine" and carry a pull-to-choke marking. The record also lists operation and lubrication instructions, an emblem reading Alcoa and a shield with Kiekhaefer Mercury SKE 9822-1. The text read gives no year. Source: Jack Morgan Museum record 2010.2.292.

What the three records say about the engine and the chain

The Swedish record gives the engine as a Mercury of 3.5 horsepower, and the Jack Morgan Museum record carries the Kiekhaefer Mercury inscriptions on the engine itself. The patent does not name an engine: it deals with the chain and its drive sprocket. The patent was granted on October 25, 1949, one year after the Swedish record's 1948 to 1949 period begins. The records do not say whether the patented chain was fitted to either saw. A second United States patent, 2,618,298, was applied for on December 27, 1949, and granted on November 18, 1952, naming Henry C. Pratt of Philadelphia as inventor and Henry Disston and Sons, Inc., as the party he assigned it to; one stated object is a chain guide rail made of one integral piece of metal.

A chain saw patent filed in 1943 by a Chicago firm is on the page about Mall chainsaw history. How the later standards and brake rules treat saws is on the page about chainsaw kickback and chain brakes, and the page about the chainsaw history timeline sets all of the makers in date order.

To correct or remove an entry, write to the address at the foot of this page.

Disston chainsaw history: dated facts from two United States patents and two museum catalogue records

Dated facts

What the three records say about the engine and the chain

Sources