The present invention relates to method and device invention made in SS316LN for tuning single-cell or multi-cell SCRF cavity for precise slow and fast tuning with low hysteresis. The tuning mechanism (device) for SCRF cavity consists of two thick square flanges connected to each other through two parallel sets of X-link levers pivoted in between such that the motion of top end of flange and bottom end of flange equalizes; wherein the top end of X-link connects one square flange to the bottom end of the other square flange and vice-versa using thin flat flexure plates; wherein the flexure plates are joined on X-link and square flange by bolts having spring locks; the square flanges have platform on the top that transfer motion and these are connected through power screw mechanism; wherein the power screw for linear actuation is rotated using worm-wheel.