I made plastic jaws for a benchvice 120mm wide. It has some holes to put 10x2mm magnets to hold them in place. and the clamping side has 3 different vertical and one horizontal angle in it to clamp tubes in different sizes. 

I printed it with PETG with 100% Infill. To be honest, they dont replace injection molded ones or aluminimum ones. The printed ones will break sooner and dont hold up the same pressure. Also it gets difficult when the clamped parts are heated or get hot. 

Maybe with other material (Nylon for example) it has better mechanical properties but for my use that was easily tough enough.