57 fig3 when the canister 200 is inserted within the toolholder 10 as will be explained the canister protruding key portions 220 will also engage a portion of the toolholder support member 230 fig3 thereby restraining rotation about the longitudinal axis 56 between the toolholder 10 and the tool support member 230 the canister rearward end 204 must be acted upon to displace the canister along the longitudinal axis 56 for this reason extending into canister 200 from the canister rearward end 204 may be a threaded bore 235 with threads of a specific pitch and threaded in a specific direction finally at the canister forward end 202 may be a canister bump off 260 this feature as will be seen permits the canister to advance against the toolholder 10 to urge the toolholder 10 away from the toolholder support member 230 when the toolholder 10 is to be released while the canister 200 is generally rectangular the forward portion 202 is preferably cylindrical to be compatible with the cylindrical toolholder shank 45 fig3 the canister 200 may also include a spring cavity 265 extending inwardly from the forward end 202 to accept a spring 215 fig3 for urging the canister 200 away from the toolholder 10 returning to fig4 it is.