Online Catalogue last updated 17th of September 2023
You get a complete reprint of Machinery Reference Series Booklet No. 25 from 1910 and two later articles from Machinery Magazine.
Part one covers the basic problem of deep hole drilling using twist drills, flat drills, getting chips out, errors in drill sharpening, number of desirable edges and so on.
Next, you learn how the big boys could accurately drill out a cannon barrel and then bore it using a forged gun-steel boring bar over 61' long and 11" in diameter. Other examples are also discussed.
The final topic covers the construction of deep hold drills needed to drill out spindles of machine tools and axles of steam locomotives. Obviously you don't need to drill forgings this large, but the principles hold. These methods did produce remarkable precise machines and armaments.
Finally, two articles from Machinery Magazine of the 1920's discusses how a mistake created a remarkable result while boring shotgun barrels, and how one machinist made a drill bit to cut a 9/32" hole more than 15" deep.
Code No. 009588, 48 pages, $15.00