▁performs ▁the ▁gr inding ▁action ▁by ▁having ▁a ▁higher ▁tang ential ▁speed ▁than ▁the ▁work pie ce ▁at ▁the ▁point ▁of ▁contact . ▁The ▁other ▁wheel , ▁known ▁as ▁the ▁reg ulating ▁wheel ▁( mov ing ▁wheel ▁in ▁the ▁diagram ), ▁is ▁mov able . ▁This ▁wheel ▁is ▁position ed ▁to ▁apply ▁later al ▁pressure ▁to ▁the ▁work pie ce , ▁and ▁usually ▁has ▁either ▁a ▁very ▁rough ▁or ▁rub ber - b ond ed ▁ab ras ive ▁to ▁trap ▁the ▁work pie ce . ▁ ▁The ▁speed ▁of ▁the ▁two ▁whe els ▁relative ▁to ▁each ▁other ▁provides ▁the ▁gr inding ▁action ▁and ▁determ ines ▁the ▁rate ▁at ▁which ▁material ▁is ▁removed ▁from ▁the ▁work pie ce . ▁During ▁operation ▁the ▁work pie ce ▁turns ▁with ▁the ▁reg ulating ▁wheel , ▁with ▁the ▁same ▁linear ▁velocity ▁at ▁the ▁point ▁of ▁contact ▁and ▁( ide ally ) ▁no ▁sli pping . ▁The ▁gr inding ▁wheel ▁turns ▁faster , ▁sli pping ▁past ▁the ▁surface ▁of ▁the ▁work pie ce ▁at ▁the ▁point ▁of ▁contact ▁and ▁removing ▁ch ips ▁of ▁material ▁as ▁it ▁passes . ▁ ▁Types ▁There ▁are ▁three ▁forms ▁of ▁center less ▁gr inding , ▁differenti ated ▁primarily ▁by ▁the ▁method ▁used ▁to ▁feed ▁the ▁work pie ce ▁through ▁the ▁machine . ▁ ▁Through - feed ▁In ▁through - feed ▁center less ▁gr inding , ▁the ▁work pie ce ▁is ▁fed ▁through ▁the ▁gr inding ▁whe els ▁completely , ▁entering ▁on ▁one ▁side ▁and ▁exit ing ▁on ▁the ▁opposite . ▁The ▁reg ulating ▁wheel