Abstract: An improved plate adapter for use with flexible couplings is disclosed which incorporates radially outwardly disposed pilot flanges for engagement with the hub and sleeve of the half coupling which pilot flanges are designed to form a pressfit relationship with the mating surfaces of the hub and sleeve. A suitable bolting arrangement is provided to aid in fitting of the adapter plate to the half coupling as well as to assist in removal of same. Additionally, the fastener arrangement enables fine adjustment of the radial runout of the sleeve of the half coupling relative to the axis of rotation of the shaft to which the half coupling is secured.