A Bridgeport Milling Machine is a great addition to any machine shop due to its power and versatility. In order to run one effectively, you must understand basic machining concepts. If you use the Bridgeport improperly, you may not only damage the machine itself, but your tooling and fixtures as well. Operating a Bridgeport takes patience, thoroughness and experience and the reward is the manufacture of accurate, quality parts.
Turn the main power on to the machine. A Bridgeport usually needs a breaker unto itself. It runs on 220 volts and is a very powerful machine, so keeping it separate from other machines is a wise choice for any machine shop.
Turn the spindle on. There is a switch located on the head of the machine. Turning it to the right will activate the spindle in a clockwise direction as long as the motor is in the high gear. It would be the opposite in low gear. Turn the spindle on to adjust the speed of the spindle.
Use the speed control wheel to set the RPMs needed for the tool you plan on using. It is often wise to adjust the speed before inserting the tool as it may be set very fast and cause the tool to become loose when you start it.
Insert the tool into the spindle. Loosen the draw bar if there is a tool in there already by loosening the nut located at the top of the spindle, insert the collet and re-tighten the draw bar to keep the tool secure.
Clean the table from debris. It is always best to clean the table before attaching a vise to the table. The vise must be flat for accurate cuts, so cleaning metal chips and dirt from the slots as well as the surface can help this occur.
Secure the vise or work-holding fixture using T nuts in the slots. You will also need to tram the vise to make sure it is straight. Use a dial indicator swept across the front to tram the vise for accurate X-axis cutting.
Always use coolant when cutting. Either attach a mister or use a hand-held spray bottle of coolant to keep everything cool. Heat can damage raw material as well as tooling. Drill can break and endmills can be damaged by excess heat, so utilize coolant whenever you can to prevent premature failure of tooling.
Run the endmills and drills at reasonable feed rates and make sure that your RPMs are set correctly based on the tool itself and the material being cut. You can always run your feeds and speeds high with aluminum, but watch both settings when working with steel of any kind.