Some 520 employes in the manufacturing plants of the J. Wiss & Sons Co. of Maplewood and Newark returned to work this morning after a two-day strike over grievance procedures. A meeting of management and representatives of Amalgamated Local 301. Wholesale and Department Store Union, AFL-CIO, was scheduled for 1:30 p.m., to discuss the issues.

The strike began shortly after the start of the workday Monday at 7:15 a.m., when several workers walked off their jobs in the firm's garden tools plant at 228 Burnett Ave., Maplewood. By noon they were joined by most of the plant's 400 workers as well as over 100 workers in the scissors and shears plant at 33 Littleton Ave., Newark.

Alfred C. Urffer, personnel director for Wiss, called the strike "illegal." He said a two-year contract with the union expires in October. Under its provisions, work stoppage is prohibited and all grievances must be submitted to arbitration.

Urffer said union officials asked to meet with the company yesterday but were told the return of workers to their jobs would be a prerequisite to any talks.

Employes returned to work after a meeting in Slovak-Sokol Hall in Newark this morning, when it was decided to ask for a meeting with the company this afternoon.