Another principle in planing machines which deserves notice is the manner of driving carriages or platens; this is usually performed by means of spur wheels and a rack. A rack movement is smooth enough, and effective enough so far as a mechanical connection between the driving gearing and a platen, but there is a difficulty met with from the torsion and elasticity of cross-shafts and a train of reducing gearing. In all other machines for metal cutting, it has been a studied object to have the supports for both the tools and the material as rigid as possible; but in the common type of planing machines, such as have rack and pinion movement, there is a controversion of this principle, inasmuch as a train of wheels and several cross-shafts constitute a very effective spring between the driving power and the point of cutting, a matter that is easily proved by planing across the teeth of a rack, or the threads of a screw, on a machine arranged with spur wheels and the ordinary reducing gearing. It is true the inertia of a platen is interposed and in a measure overcomes this elasticity, but in no degree that amounts to a remedy.
Hurriedly the youthful Sky Patrol tumbled onto the sand, digging cotton plugs out of their ears now that the roar of the motor no longer made them essential.
ONE:Rene Lalage made his way blindly up to the roof, where he lay breathless under the shadow of a chimney. It was too dark to study any further plan of escape, and too dark for a free dash for liberty. A false step and he might be dashed to the ground. Better be caught and taken back to gaol than that.
TWO:As he said this the commander put his hand roughly on the shoulder of the trembling man, who again said in French:
TWO:Gilbert Lawrence lighted a cigarette and waited for Bruce to speak. It wanted some little time to luncheon. The doctor's statement was likely to add piquancy to the meal.
THREE:"The more I thought it over the more certain I became that my brain had been picked, and that my plot was being used by some designing person to bring trouble and disgrace upon a man who is destined to be related to me. I waited for a little time to see how matters were developing, and then decided to refresh my memory from the skeleton plot of that unwritten story. When I looked in my desk I could not find the plot. Why? Because it had been stolen.
