A turbine wheel and bucket assembly comprising a wheel having a peripheral rim machined to include a dovetail shape about the circumference of the rim, interrupted only by a bucket installation slot; and a plurality of buckets installed on the wheel, each bucket having a dovetail portion and blade portion, with the dovetail portion machined to include a complimentary dovetail shape enabling each bucket to be slidably received on the wheel dovetail shape; each bucket having an integral cover at a radial tip of the blade portion, each cover having axially extending surfaces on either side of angled contact surfaces adapted to engage mating contact surfaces of adjacent covers such that the buckets are pretwisted in a first direction. The dovetail shape includes a keyway and a complimentary key is provided on the rim of the wheel, the key receivable within the keyway to prevent rotation of the dovetail portion of the bucket relative to the wheel.