When working with a 1-ton hand hoist chain, it is essential to avoid oblique pulling. Keeping the lifting operation as vertical as possible is crucial for the proper functioning and safety of the hoist. 

Pulling at an angle can put excessive stress on the components of the hoist and may lead to premature wear or even failure. It can also cause the load to swing or become unstable, increasing the risk of accidents. 

By strictly adhering to vertical lifting, we can ensure the longevity and reliability of the hand chain hoist while minimizing potential safety hazards. Always strive to maintain a straight and upright pulling direction for a smooth and safe lifting experience.