There are many sizes and types of bolts, washers, screws and nuts in both metric and Imperial units. They come in a variety of materials with a variety of coatings. Bolts and screws provide service as fasteners. Washers serve the purpose of distributing the pressure from the bolt or screw head across the surface of the object it is screwed into, and decrease the chance of the bolt or screw from loosening through time and wear. Lock washers are placed between the bolt head and washer to create a higher pressure between the bolt head and the surface being screwed into, decreasing the chacne of loosening even more.
Bolts and nuts must have the same thread values, with a degree of freedom between them to allow turning and prevent binding. Bolts and nuts have matching thread measurements, which are conveyed in terms of threads per inch, thread pitch, depth, etc. Bolts may have additional variants such as runout, shank, radius, and grip length measurements.
Solid modeling nuts bolts washers and screws is mostly a case of logically defining and tracking the measurements of each part, and making sure bolts match appropriate nuts, that washers fit, and the materials and textures are correct for the assigned part. Lighting and studio setup are important to correctly represent the materials and tetures, and to best represent the product for the project at hand.
