The general results, when a waggon weighing 21 cwt was used on different sorts of roads, are as follows: lbs 1. On well-made pavement, the draught is 33 2. On a broken stone surface, or old flint road 65 3. On a gravel road 147 4. On a broken stone road, upon a rough pavement foundation 46 5. On a broken stone surface, upon a Bottoming of concrete, formed of Parker's cement and gravel 46 The following statement relates to the force required to draw a coach weighing 18 cwt.
"On the Economy of Machinery and Manufactures"
Charles Babbage
The plug and Bottoming taps are made parallel in the thread, the former being tapered slightly at and for two or three threads from the entering, as shown in Fig.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose
In the third or Bottoming tap, Fig.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose