Document z0rnMx7VBpy4Z27jnV1qrYV0

side. In brief the Unitool Method covers the following: (a) spiral bevel and Zerol bevel gears of any ratio. (b) hypoid gears of 3 to 1 ratio and higher. (c) all reasonable tooth numbers, pitches, spiral angles, and pressure angles. (d) all reasonable tooth designs including equal-addendum teeth as well as stand ard long-and-short-addendum designs, stub teeth, and special root line direc tions. (e) the same cutter is used for both members of the pair. (f) each part is completed before remov ing from the cutting machine. (g) one cutter covers a wide range of work. (h) five cutters cover the range of work which may be cut on this machine. (i) roughing is generally performed with the finishing cutter. (j) . calculations for machine settings are comparatively short. Most high-quality production jobs are produced using the spread-blade method for finishing the gear and the fixed-setting method for finishing the pinion. In automotive plants it is customary to make the gear Formate (that is, not generated) by the Single-Cycle method on a Single-Cycle Gear Finisher. The mating pinion is then generated by the fixed-setting method on this machine. CUTTING PROCEDURE This machine is most commonly used in the quantity production of spiral bevel and hypoid pinions by the fixed-setting method. Such ma chines are usually equipped to do only the finish ing operations. The rough cutting of the pinion tooth spaces is done on a separate machine designed specifically for that purpose. Where more than one finishing machine is used, the two sides of the pinion teeth are cut on separate machines. The usual procedure is to finish the con cave sides of the teeth first and the convex sides second. When the No. 116 Hyppid Generator is used for the cutting of general work,, it is arranged so that it can also do the preliminary roughing operation. All pinion members and gear members with pitch angles of 68 or less are roughed with generating roll using the cutter and set-up data given on the summary for that purpose. The set-up of the machine for this type of cutting is slightly different than finish cutting and it is fully explained in the set-up instructions herein. Gear members with pitch angles greater than 68 are normally roughed without generating roll. This is done by replacing the roll gears with a special locking yoke and using a different path in the feed cam. This cam path (engaged by roller "A") feeds the work into the cutter at a gradual rate. Details on how to make this set-up are given in the instruc tions. After the gear members are roughed, both sides of the teeth are finished in one set-up by either the spread-blade or the single-setting process. A locating pin in the work-holding equip ment or a stock-dividing gage is used in position-ing the roughed pieces so that approximately the same amount of stock is removed from the two sides of the teeth. Pinions which are being pro duced in quantity by the fixed-setting or single side method are normally positioned in the work holding equipment for each finishing cut by means of a stock-dividing gage. The usual practice is to finish cut the concave side first. Pinions which are being cut by the Gleason Spiral Bevel Gear Jobbing System are sometimes finished on both sides in one cutting procedure. After one side is finished, the eccentric angle, sliding base, and blank position are set for the other side. The blank is then rotated by means of the index set-over clutch an amount which has been determined experimentally to produce the correct tooth size. The second side is then cut. This pro cedure is recommended only when a very few pieces must be cut. A somewhat similar procedure is followed in the Unitool method for roughing and finishing both gear and pinion. After the.Unitool cutter has been mounted and the machine set for the gear, the steps are as follows: 1. Take a central cut on the gear. 2. Rotate the blank an amount equal to one- half the gear set-over and finish cut one side of the gear. 3. Rotate the blank the amount of the gear set-over in the other direction, and finish cut the other side of the gear. 4. Set the machine for cutting one side of the pinion and take a central cut. 5. Set over and finish cut the first side of the pinion. 6. Change the eccentric angle, sliding base, and head setting for the second side. 5 GLEASON-000219