Machining Blueprints

There are many different types of trades that use machining blueprints. Some are engineers, architectural, welders, pipe fitters, die makers, and carpenters. Before reading machine drawings, you need to learn and understand the common talk and symbols that are used. Tolerance that you will find on blueprints will be written down on the drawing as a plus or minus amount. It can also be either a fraction or decimal.

There are several different ways tolerance shows up on a print. One is called unilateral method, which is when the design size varies for only one direction only. The second is bilateral, which is the dimensions that show the plus or minus amount. The third is limit dimensioning, which is the minimum and maximum measurements on both sides.

Surfaces being worked with also have full size characteristics like roundness or straight up and down to another surface. Datum is known as a surface a line or a point at which geometric area is to be measured for distance. Fillets make metal corners stronger. It is an inside concave metal corner surface. Rounds are outside corners that help to prevent chipping around sharp edges. Keys, key seats and keyways are a wedge of metal that go between slots or grooves so it will stop the shaft and hub slipping.

There are many different kinds of screw threads that draftsmen use. They are simplified, schematic, detailed, and tapered pipe threads. Draftsmen usually show symbols that are not drawn to size on the print. Make sure you read the key box at the bottom of the prints for additional information to follow.