The fourth wedge-shaped segment 92  is then disposed on the drum core adjacent the section 58, and the third wedge segment 98 is disposed between the wedg• 92 and IP。e first semi-cylindrical section 82 for completing the alternate  rise grooving system  on the  drum。

Conventional  Rise—Bias  Cross-Over  Grooving 5ystem

The conventional rise—bias cross-over grooving  sys- tem is substantially identical with the conventional rise grooving system  and is depicted  in FIGURES  12 through

15。 Substantially the only difference bet'veen the two con- ventional rise grooving systems is that the standard or straight conventional rise hereir。before set forth is pro- vided with cro!ss-over s•ctions or areas disposed substan- tially longitudinally on the drum core in  alignment  with the longitudinal axis thereof。 On the other hand, the conventional ri•e—bias cross-over grooving is provided with a cross-over  s•ction  or area which  is canted or  o8- set with respect to  the  longitudinal  axis  of  the  drum core。

In order to provide the conventional rise—bias cross- over grooving system on a drum core,  the  desired par- alter grooved sleeve 18 is se1ect•d and is cut and re-as- sembled  on  the  drum  core  as follows:

The sleeve 10 is cut or slit along the canted lines 100, 102, 104 and 106, and in addition, is cut along the sub- stantially longitudinal lines 188 and 110。 Prior to the slitting operation, a complete groove 112 is removed be- tween the lines 180 and 102。 This cutting operation pro- vides the sediments IU, 116, 118, 120, 122 and 124。 The severed segments may be  separated  and  re-arranged  in the manner as hereinbefore set forth whereby the wed;;e segments 116 and 118 are intercham。ged between the semi-cylindrical sep• rents 114 and 120, and the wedge seg- ments 122 and 124  are  simiiarly  interchanged  between the semi-cylindrical sections 120 and TU, as shown in FIGURE 13。 Th>• usual end filler bars 126 and 125 are disposed adjacent the drum flanges 130 and 152, as here- inbefore  set forth,  and the  conventional  rise    bias cross-

the  parallel  grooved  sleeve  10 of  the  desired  diameter is

- selected,  and  is  cut  and  re-assembled   on  the   drum    core in the manner hereinbefore set forth。 OF course, it is necessary to cut the sleeve 10 slightly differently to pro- vide  this  type  of yooving。

The cylinder 10 is slit or cut longitudinally  along the lines 68, 70, 72 and 74 as set North in the previous em- bodiment。 One full groove 76 (FIGURE  8)  is removed from th• sleeve 10 between the cuttin(; lines 68  and 74 prior 。to the  s1iitinp•  or  cutting  operation。  In addition, the sleeve 10 is cut or slit along the canted or diap•ona1 lines 78 and 88, thus pifiinp• the cylinder 10 into several se;;ments, namely: a substantially semi-cylindrical  por- tion 82, a first wedge-shaped segment 84, a second wedge- shap•d segment 86, a second substantially semi-cylindrical section 58, a tifird wedge-shaped segment HO, and :i fourth

40 over  grooving  system may  be  provided  on  a drum core。

Alternate  Rise—Bins  Cross-Over  Grooving 5ystem

The alternate rise—bias cross-over grooving system is substantially   identical   with  the   alternate  rise  grooving

65 system and is depicted in FIGURES 16 throu¿;h 19。 Sub- stantially  the  only  difference  between  the  two  alternate