Rolls-Royce Archives
         « Prev  Box Series  Next »        

From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Feature on a Fafnir-Cleveland spindle mounting using Super-Precision Fafnir Duplex Ball Bearings in a Cleveland Single Spindle Automatic machine.

Identifier  ExFiles\Box 115\2\  scan0550
Date  1st November 1940 guessed
  
Mariora, a Native of Romania . . .
spins the wool for her wedding gown. Peasant girls begin at thirteen to fill their marriage chests with costumes and household goods which they spin, weave and embroider with their own hands. They marry at sixteen or seventeen.

An unusually rigid spindle application, this rugged Fafnir-Cleveland mounting is so designed that more than one bearing supports the end-thrust in either direction, thereby permitting heavy drilling and counterboring operations.

Super-Precision Fafnir Duplex Bearing with composition retainer. Both back-to-back and tandem arrangements are used by Cleveland.

Another preloaded Duplex pair on the back end of the spindle gives the necessary rigid radial support, while still allowing shaft expansion or contraction, inasmuch as it is held laterally at the other end. This complete spindle mounting met with the whole-hearted approval of the Cleveland engineers, and because it has been extremely successful in its operation and performance, seems to be fully deserving of the unusually fine reception which it has received to date.

tional. An innovation in the machine tool field, this design consisted of a multiple assembly of Fafnir Duplex Ball Bearings — installed in two preloaded tandem pairs directly abutting and opposing each other—on the front end of the spindle.

This type of mounting permitted the incorporation of a sufficiently large preload to provide the necessary rigidity required for heavy cuts at low speeds. Yet at the same time a pro-rating of this relatively heavy preload among the several bearings permitted them to operate smoothly without any danger of over-heating at the high speeds encountered with light work. And the opposed pairs insure large end-thrust capacity in both directions. Such a design involves precise calculation of the preloading to be imposed, but is most desirable in that it eliminates any need for adjustment of the spindle when changing speeds.

The foundation of the new Cleveland Single Spindle Automatic is a heavy, one-piece bed such as has been standard practice for many years. This machine is built in two different sizes, one having a chuck capacity for handling round stock up to 1 1/16" in diameter, while the other can handle stock up to 1 3/8". There are three ranges of spindle speeds with twelve changes in each range. Metallic friction clutches are used for the spindle speed changes and reversals, controlled by quick-acting “load-and-fire” clutch shifters. The outstanding feature of the feed drive is the universal cam, which makes pos-

13
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙