Manual drafting use a variety of triangles to layout piping drawings. While electric erasers are not necessary, they make the job of erasing much easier and faster. Pencils and leads come in a wide range of sizes and shapes. Drafters usually use a 4H lead to draw projection lines and guidelines, and use an H or F lead for other line work and lettering needs. Line thickness also has an important role on piping drawings. A.7mm or wider lead holder is commonly used on major elements of the drawings such as pipe and lettering. Background components such as equipment, foundations, support structures, and dimension lines are typically drawn with a .5mm lead.
One cannot stress enough the importance of quality line work and lettering. Manual drawings are run through blueprint machines. This requires that lettering and line work be neat and of good quality to maintain clarity of dimensions and callouts.