(1) In case one is not tightened cylinder flange bolts, large cap to be a datum, a little push to move around the large cap, according to color to repair and scrape the combination surface of down cylinder. This method is suitable for small size, good stiffness, vertical arc of cylinder.

(2) The other is for a larger size, less rigid cylinder, must be uniformly tightened bolts in cylinder combination (tightening does not have to be too much), in the case of the elimination of the gap caused by the vertical arc, use feeler gauge for measuring the existing gap, scrap stepwise according to the gap.