Overlock machine upper looper position and timing

It,s Garments M/c Mechanics Tutorial Channel, Our Address ;-Grameen Shikkha Vocational Training Center, B12/12 Talbag, Savar, Dhaka, Bangladesh. Phone;- 01732043116. Our Another Trades ;-1. Electrical Trade, 2. Computer Trade, 3. Garments M/c Operator Trade.