the center of the housing 255 a steel pin 264 is positioned in the bore 263 a circular ridge 265 is formed around the hub 262 which forms a recess 270 between the ridge 265 and the ridge 258 on assembly the cover 236 is rotated far enough for the tabs 260 to clear the flanges 256 the pin 264 is aligned with the hole 252 in the trolley 234 and the cover rotated to interlock the tabs 260 with the flanges 256 the rotary cutting blade 218 includes a center opening 269 and is mounted on the pin 264 in abutting engagement with support surface 254 when the cover 236 is mounted on the trolley 234 it should be noted that the recess 270 provided around the periphery of the ridge 265 accommodates the cutting blades 218 having cutting edges offset from the center of the blade in this regard a pinking blade 272 or other types of blades can be stored on the pins 217 in recess 215 a pinking blade 272 is shown in fig1 mounted on pin 264 the pinking blade 272 has a center section 282 and a cutting edge 284 offset from the center section 286 into the space 270 provided in cover 236 the trolley 234 is mounted on the rail 224 by sliding the leaf springs 248 into the inside of the rail with the flange 244 aligned with the outside of the rail 224 one of the cutting blades is mounted on pin 264 and.