General Specifications for NRG COMPANY, INCORPORATED Chain and Flight Skimmer Equipment Part 2 - Products 2.5 Skimmer Sprockets   Sprockets shall be made from Ultra High Molecular Weight Polyethylene (UHMW-PE) material, minimum molecular weight of 4.5 million, and maximum relative abrasion resistance of 15. The UHMW sprocket shall be split to facilitate installation. The sprocket hubs shall be secured by four (4) 1/2" diameter stainless steel bolts. The two sprocket halves shall be secured to the hub by six (6) 3/8" diameter stainless steel bolts. Sprockets shall include two (2) 1/4" diameter bolts to ensure alignment of the two halves. The sprockets shall have a minimum tooth thickness of 15/16" and minimum length through bore of 3 15/16". Sprockets shall be hunting tooth type. Head shaft sprockets shall be secured to the head shaft by keys and set screws. The head shaft sprockets shall have ___ teeth (23,19,or 17). Idler and take up shafts shall include one sprocket which shall turn freely between two set collars and one which shall be set screwed in place. The idler shaft sprockets shall have ___ teeth (23,19,17,13). Sprockets molded from Nylon-6 are also acceptable.