Lead angle

Lead angle A method of setting the direction of the wellbore in anticipation of the bit walking. 

Angular dimensions that define gears and are used in their specification and design are helix angle, lead angle, shaft angle, and angular pitch. 

BOTTOM MOTOR W ElCiHT ASSEMBLY w TO dial INDICATOR KOR LEAD ANGLE ADJUSTMENT... 

Lead and tilt angles (Fig. 8a). Lead angle a, also called Sturz angle, is the angle between the normal vector Nl and the projection of the... 

Fl X Nl) axis. In a case when the tool orientation vector Tl is within the Fl-Nl plane, tilt and screw angles become equal to zero, and lead angle is equal to inclination angle. 

In five-axis tool path generation, the tool inclination can be constant (e.g., constant lead angle) or optimized in each point of the surface to be machined. Especially when end mills or toroidal tools are used, the tool inclination can be optimized for maximal machine strip width. In other words, the tool inclination can be set so the curvature of the tool in the tool contact point perfectly fits with the curvature of the surface in a direction perpendicular to the feed direction (Fig. 18) (Dejonghe 2001). This can be expressed in the following equation ... 

Fig. 5.1 Pacemaker patient, anteroposterior chest X-ray. Two functional bipolar leads (atrial and ventricular) are connected to a device housed in a lower left subclavicular region there are also two abandoned, nonfunctional bipolar leads (both in the right ventricle). Note the three anatomically crucial lead extraction points A, the subclavicular region where the leads lie between the clavicle and the first rib B, the innominate-superior vena cava junction, noting lead angle at that level C, lead-tip position in the right ventricle...

Mechanical Pretightening. Mechanical pretightening is accomplished with wrenches. This method may result in torquing the stud rather than tightening the nut. The accuracy of torque is based on the lead angle of the threads and the frictional characteristics of the overall assembly. These coefficients are variable and depend on a number of factors. 

FIGURE 8.1 A 34 mm diameter screw used in a corotating twin-screw extruder. The lead angle and length (in mm) are given for each section. (Data from Biesenberger et ah, 1990.)... 

See Fig. P-21 for a definition of lead angle.) With this rubbing speed noted at the bottom of the diagram, read vertically upward until you intersect the coefficient-of-friction curve. Read the value of the coefficient of friction from the left-hand side of the diagram. 

When the worm is the driver, enter the efficiency diagram with the lead angle of the worm at the bottom of the diagram. Read upward to the intersection of the curve with the correct coefficient of friction. The efficiency of the gearset may be read from the right-hand side of the diagram or the efficiency loss on the left-hand side of the diagram. 

For low ratios the minimum pitch diameter is governed by the desirability of avoiding too high a lead angle. Lead angles up to 50° are practical. 

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