Retrofitting is addition of components, features or accessories on older system that did not have when it manufactured. It is used to carry out various operations on same machine. Retrofitting is considerable change in current machine to make it flexible for doing various operations. Here is retrofitting for gear lapping on lathe machine. Its reduces high investment cost to buying separate gear lapping machine. It is economical for all small scale industries and medium scale industries. Gears are key to power transmission in our day to day life. Mechanical power transmissions uses belt, chain and gears for power transmission. This paper includes how to use the gear lapping process & innovative way of gear lapping machine. We can use conventional lathe machine which is present in most of the machine shop. The attachment is designed on simple design and is easy to use. It may include different types of gears. Whichever cutting process is used, tooth surface errors appear, in part because of tooling wear and machine distortion, in part because the gears are heat treated after cutting which releases internal strain and causes tooth flank distortion. Therefore, a finishing operation is necessary. As a result, excellent smoothness and quietness of operation can be obtained