 Welcome to an overview of the Bridgeport milling machine. In this learning activity, we'll identify the parts that make up the Bridgeport and learn how it works. Milling machines are very versatile. They're used to drill, bore, mill pieces, and produce slots. The Bridgeport milling machine is a typical vertical milling machine, which means it has a vertical spindle with a swiveling head. 1. Parts of the Bridgeport The main parts of the Bridgeport mill are the base, column, knee, saddle, table, ram, and tool head. Base The base supports the milling machine. The leveling screws in the four corners allow you to level the machine if the floor is uneven. Column The column rises from the base. It holds and allows the knee to move up and down by the dovetail on the column. The top of the column is also machined and it supports the ram, which is mounted to it. Ram The ram moves back and forth. Tool head The tool head is mounted to the ram. It consists of an electric motor, a motor switch, a spindle brake, a variable speed control, a range lever, a quill, a quill lock, a quill feed hand lever, a quill feed rate selector, a quill feed engage, a quill feed trip lever, and a quill stop. Knee The knee is mounted to the column and it moves up and down. The knee supports the saddle and the table. Saddle The saddle moves in and out and supports the table. Table The table moves left to right. This is where you mount the workpiece. 2. Lubrication Within understanding of the bridge port's parts, let's learn how to take care of the machine and how to get it ready for use. Proper lubrication is essential to keeping the bridge port milling machine working. You should pull the hydraulic oiling system every day to ensure the machine is getting lubricated. This system provides lubrication for the entire machine. If the oil is low, you'll need to add whey oil to the reservoir. You should also add a few drops of light hydraulic oil in the oil cups on the tool head. 3. Locks The bridge port has locks for the knee, saddle, table, and quill. These allow you to lock an axis during the machining. The knee, saddle, and quill each have one lock. The table has two locks. Turning the lock clockwise locks it. Turning it counterclockwise unlocks it. 4. Moving the table, setting zero with digital readout. The table is your x-axis. Its orientation is based on facing the front of the machine. The table moves left and right. You can manually move the table using the hand crank on either end, or you can use the power feed motor. You can use the collar to set the collar to zero. However, the most common way to set zero when you're moving the table is to use the digital readout. It's easy to do. Position the table where you want x-zero to be, and press the x-zero button on the digital readout. 5. Moving the saddle, setting zero with digital readout. You can also move the saddle by hand using the crank handle. The saddle is the y-axis. You can use the crank handle to set zero, or you can press the y-zero button on the digital readout. 6. Moving the knee, setting zero. You can move the knee up and down using the knee traverse crank. You can set zero on the knee by moving the collar until the zero and the line matches. 7. Moving the quill, use the hand lever to move the quill up and down. You can adjust the quill stop to set how far the quill will go down. 8. High and low gear. The bridge port has high gear and low gear. Use the high neutral low lever to change gears. The spindle can't be on while changing gears. You may need to manipulate the spindle in order to get the gears to mesh. 9. Setting the RPM. You can only change the RPM while the spindle is turning. Use the variable speed control to adjust it. Turning the control clockwise lowers the RPM, and turning it counterclockwise increases the RPM. Depending on which RPM range the machine is currently in, you'll see either the high or low range on the display. 10. Spindle clockwise and counterclockwise. Now let's learn how to use the bridge port milling machine. Use the motor switch to turn the spindle on and off. The range you're in and the direction you want the spindle to turn dictates if you run the motor in high or low. In high range, you run the motor on high to turn the spindle clockwise. You run it on low to turn the spindle counterclockwise. You must completely stop the spindle before switching directions. Apply the brake using the spindle brake lever to stop the movement. 11. Setting the feed rate on the x-axis using the auxiliary feed. You can use the auxiliary feed motor to feed the table in the x-direction. The control feeds in both directions and has a variable speed. To change the feed speed, turn the adjuster knob on the power feed. The direction lever has three positions, off, left, and right. The lever points in the direction the table is going to move. While the table is feeding, you can use the rapid button to feed it as fast as possible. It's important to remember that the numbers on the dial don't correlate to inches per minute. When setting your feed rate, you zero out your x-readout. Then you use a clock to see how far the table travels in 10 seconds. Multiply this distance by six to calculate the travel speed in inches per minute. Once you have this calculation, make your adjustment, test, and calculate again. 12. Power feeding the quill. Power feeding is used for many operations. One of the most popular is boring. Begin by setting the quill to feed at a certain feed and moving either up or down. Engage the quill feed engage lever. It can only be engaged if the spindle is off, and it cannot be engaged if the RPMs are over 3,000. Next, set your feed rate with the quill feed selector. There are three different feed rates. .0015, .003, and .006. And each one is in the thousands per revolution. You'll also need to set the feed reverse knob. The three settings are down, up, and neutral. All the way in is the down setting. All the way out is the up setting, and the middle is the neutral setting. Always disengage the quill feed engage lever when you're done using the power feed on the quill. 13. Adjusting the head. You can adjust the head in one of two spots. The first is in the front of the tool head. Loosen the first nut and then just snug it so that when you loosen the other three, the head doesn't fall. Then use the swivel bolt to move the head. If you're moving the head more than 25 degrees, you need to pull out the safety pin. When the head is in the desired position, start snugging the lock nuts. When all four lock nuts are snugged, go through and do a final tightening on them. The second way you can adjust the head is behind the tool head. Again, begin by loosening the first bolt and then snug it up to prevent the head from falling. Loosen the other two bolts and use the swivel bolt to adjust the head to its desired position. This adjustment doesn't have a safety pin. Snug up all three bolts and then tighten all three bolts. 14. Loading, unloading a tool. The bridge port uses a threaded drawbar to clamp the tool into the spindle. The tool holder, or collet, has internal threads and the drawbar has external threads. The drawbar's external threads fit inside of the tool holder. Also on the tool holder, there is a keyway and in the spindle, there is a key. After ensuring the spindle taper and tool are clean, put the tool into the spindle. You might have to rotate the tool holder to get the key and keyway lined up for the tool holder to go up into the spindle. Then start threading the drawbar by hand until it is snug. Then apply the brake and use the wrench to finish tightening the tool. To remove the tool from the spindle, use the wrench and apply the brake to get the drawbar free. Then turn the drawbar counterclockwise, a maximum of three turns. Use a brass hammer or a dead blow hammer to break the seal between the taper of the spindle and the tool. Never use a regular hammer when striking the end of the drawbar. Never leave the wrench in the drawbar because it will cause damage to the machine or fly off when the spindle is turned on. If you turn out the drawbar more than three turns, you run the risk of damaging the thread on the end of the drawbar. Once the seal is broken, turn the drawbar by hand until it is unthreaded from the tool. Now you can remove the tool from the spindle. 15. Conclusion Today we have examined the parts of the Bridgeport milling machine, learned how to take care of it, and how to use it. You have completed an overview of the Bridgeport milling machine. Thank you for watching.