Milling Bridgeport User Guide

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Shop Area: Metal Shop

Tool: Milling Bridgeport

Requires in-person training: Yes 

Procedure Number

UG 130-06, Rev. 1





Bridgeport Mill.png


  • Always wear approved face shield.
  • Before operating equipment, remove tie, rings, watches and other jewelry, and roll sleeves up past the elbows. Remove all loose clothing and confine long hair.
  • Non-slip footwear or anti-skid floor strips are recommended.
  • Closed toe shoes are required when working in a shop area.
  • Keep all parts of your body away from moving parts (belts, cutters, gears, etc.)
  • Remove chuck wrenches before starting the machine.
  • Stop the spindle completely before loading or unloading a workpiece.
  • Do not remove chips with hands. Use a hook or similar device and make certain that all machine movements have ceased.
  • Do not adjust tooling, workpieces or coolant hoses while the machine is running.
  • Stop the spindle completely before taking measurements.
  • Stop the spindle completely before opening safeguards or covers.
  • Never reach around a safeguard.
  • Stop the machine before changing or adjusting belts, pulleys or gears.
  • Keep hands and arms clear of spindle start switch when changing tools.
  • Prevent cutter breakage. Use correct table feed and spindle speed for the job. Reduce feed and speed if you notice unusual noise or vibration.
  • Rotate spindle in clockwise direction for right-hand tools, counterclockwise for left-hand tools. Use the correct tool for the job.
  • Never start the machine when the cutter is in contact with the workpiece.
  • Do not use worn or defective tools. Use the proper size and type of tool for the task at hand.
  • Keep rotating cranks and handwheels well lubricated and maintained. Do not remove safety springs.



Bridgeport Mill Sketch.png

HIGH-LOW RANGE SWITCH: High-Low Range Switch “A”, is a motor reversing switch. When the attachment is in direct drive (HIGH SPEED), the motor and spindle are turning in a clockwise direction as viewed from the top of machine. When the attachment is in “Back Gear” (LOW SPEED), the spindle will run backwards (counter-clockwise) unless the motor direction is reversed by moving switch to “Low”. The back gear lever is marked Hi-Lo. This will indicate the proper switch position. They should be positioned alike or the spindle will run backwards. - NOTE - Spindle should run in clockwise position.

VARIABLE SPEED DIAL: Variable Speed Dial "B", visibly indicates, in windows, the speed range that the machine is operating in, 60 to 500 low range, 500 to 4200 high range.

SPINDLE BRAKE: Spindle Brake “C”, can be moved in either direction to stop spindle; however, when locking spindle, brake lever should be moved either by pulling towards the operator or pushing away from the operator, then raised. When brake is worn out it has to be replaced. There are no adjustments to be made.

QUILL FEED SELECTOR: The Quill Feed Selector “D”, is used for selecting the three feeds: .0015”, .003” and .006” per revolution. It is shifted by pulling knob out and turning from one position to the other. Feeds are stamped on cover below indentation hole. Feed is more readily engaged when spindle is running.

QUILL STOP KNOB: Quill Stop Knob “E”, is used to disengage automatic feed in either direction as well as the stop point setting working depths.

MICROMETER NUT: Micrometer Nut “F”, is used for setting depths. Each graduation on nut indicates .001” of depth, it reads directly to scale mounted along the side of it. Depths may be obtained by setting micrometer nut in conjunction with quill stop.

FEED REVERSE KNOB: The position of the Feed Reverse Knob “G”, depends upon direction of spindle rotation. If boring with right hand cutting tools, pull feed handle towards operator until clutch becomes engaged. Neutral position is between forward and reverse position. It is recommended that the handle be left in neutral position when not in use.

MANUAL FEED HANDWHEEL: Feed Reverse Knob “G” should be in neutral position and Feed Control Lever “I”, engaged. Clockwise rotation of Manual Feed Handwheel “H”, moves quill down. The manual feed handwheel and the quill feed handle may be disengaged by moving them outward about .125”.

FEED CONTROL LEVER: Feed Control Lever “I”, engages overload clutch on pinion shaft when positioned left and will stay engaged until either quill stop comes in contact with micrometer adjusting nut, forcing feed control lever to drop out automatically, or release manually by engaging lever to right. FEED CONTROL

OVERLOAD CLUTCH: The Feed Control Overload Clutch is set at the factory to hold up to 200 lbs of down pressure on quill, which will accommodate drills up to .375” diameter in mild tool steel.

  • NOTE - The feed control lever must be engaged in order to use manual feed controls. the quill feed handle and manual feed handwheel may be removed when not in use.

QUILL: Quill “J”contains the spindle assembly and can be raised or lowered by using the quill feed handle “M”.

SPINDLE: Spindle “K”, performs the actual rotation and also retains the machine tooling.

QUILL LOCK: Quill Lock “L”, is a friction lock for use when quill is in a stationary position such as a milling operation. It is recommended that this lock be used whenever quill movement is not desired.

QUILL FEED HANDLE: Quill Feed Handle “M”, is used to raise and lower the quill manually. It is generally recommended that handle be engaged when using the power feed. It may be removed by simply pulling handle off.

POWER FEED TRANSMISSION ENGAGEMENT CRANK: Power Feed Transmission Engagement Crank “N”, engages power feed worm gear. When lever is in right hand hole, the power feed worm gear is engaged. To engage worm gear, pull knob out and crank handle in clockwise or down direction and move to opposite position.

  • NOTE - Crank should be rotated counter-clockwise to engage power quill feed. Crank should be rotated clockwise to disengage.

HI-NEUTRAL-LO LEVER: The Hi-Neutral-Lo Lever “O”, is used to put the attachment into either back gear or direct drive. Rotate the spindle by hand to facilitate meshing of clutch or gears. Neutral is provided to permit free spindle rotation for indicating and setup work. In the high-speed position (direct drive) the spindle is driven by tapered clutch teeth. If the clutch is not meshed tightly, clutch rattle will be heard. This can be corrected by loosening the two securing screws in lever while in high-speed position. The clutch spring will automatically adjust the clutch. Tighten the two securing crews in lever.

SPEED CHANGE HANDWHEEL: DO NOT attempt to change spindle RPM unless the motor is running. Dial speeds will only be approximate. Belt wear will cause a slight variation in speeds from what is indicated on the dial. Spindle speeds are adjusted by turning Speed Change Handwheel “P”, on the front of the belt housing. There are two ranges: 60 to 500 and 500 to 4200.

  • To obtain 60 to 500 (low range):

1. Hold the Hi-Neutral-Lo lever (right rear side of the attachment) so the gears are clear of one another.

2. rotate the spindle nose by hand until the gears line up, then move the Hi-Neutral-Lo lever to the “Lo” position (back gear).

3. Use the low range on the drum switch to engage the back gears.

CAUTION - If the back gears do not mesh, do not force the lever.

  • To obtain 500 to 4200 (high range):

1. Hold the Hi-Neutral-Lo lever (right rear side of the attachment) so the gears are clear of one another.

2. rotate the spindle nose by hand until the gears line up, then move the Hi-Neutral-Lo lever to the “Hi” position.

3. Set the drum switch to high range.

MOTOR: Motor “Q”, has the following specifications:

  • 2 HP variable speed (with 2J head)
  • 3 HP 30 minute duty rate

DRAWBAR: When tightening or loosening the Drawbar “R”, it is necessary to lock the spindle. To accomplish this, use the spindle brake which is located on the left side of the belt housing, pulling towards the operator or pushing away from the operator until it binds, then raise the quill feed handle. Drawbar has 7/16”-20 right hand thread and should be tightened by hand with normal amount of pressure using wrench furnished with machine. To loosen collet, back off drawbar and if collet does not open immediately, give knob on top of drawbar a slight tap. Spindle has non-sticking taper and collet should release readily.

                                                OPERATIONAL PROCEDURES

Spindle Speed: Do not change speed when spindle is stationary. Change speed only when spindle is running. To change speed within range:

1. Start spindle.

2. Turn handwheel “A”, Figure 2.16, to select required speed.

Bridgeport 2 16 17 18.png

Back Gear (Low Speed): Do not change range while spindle is running. Change range only when spindle is stationary. To change range from direct to back gear drive:

1. Switch “B”, Figure 2.17, to OFF (Stop spindle rotation).

2. Move lever “C” through neutral to LOW (This reverses the spindle rotation).

3. Switch “B” to LOW.

Direct Drive (High Speed): To change range from back gear to direct drive.

1. Switch “B” to OFF (Stop spindle rotation).

2. Move lever “C”, Figure 2.18, through neutral to HIGH.

3. Rotate spindle by hand until the clutches are felt to engage.

4. Switch “B” to HIGH.


1. Disengage Auto Quill Feed “D”, Figure 2.19.

2. Locate “F” in mid (neutral) position.

3. The quill is now under handwheel control.

Bridgeport 2 19 20.png]

AUTOMATIC FEED: Maximum loading .375” (9.5mm) diameter drill steel.

1. Ensure quill lock “G”, is off.

2. Set micrometer dial “H” to required depth.

3. Engage auto quill feed “D” when motor has stopped

4. Select feed rate “I”.

5. Select feed direction “F”, Figure 2.22.

6. Engage feed trip lever “E”. The feed will automatically trip out at a depth within .010” (.25mm)

7. Hand feed to dead stop for repeating accuracy .001” (.025mm)


Spindle Brake: Brake lever has capability to rotate in either direction to brake and lock.

1. CAM upwards to lock and prevent movement of spindle (see Figure 2.21).

Bridgeport 2 21 22.png

Quill Sensitive Hand Feed:

1. Place the handle on the quill feed shaft.

2. Select the most suitable position.

3. Push home until the locating pin engages.


Swivel Belt Housing: CAUTION - Incorrect spline alignment can be caused by unequal tightening of the locknuts ’J’ causing fluctuation of the quill feed which can be felt through the sensitive feed handle.

1. Loosen three locknuts “J”, Figure 2.23. DO NOT remove these locking nuts.

2. Swivel to required angular setting.

3. Tighten three locknuts “J” snugly before final tightening of locknuts. Run spindle to give correct spline alignment, then tighten locknuts securely.

Bridgeport 2 23 24 25.png

Swivel Turret:

1. Use wrench supplied with machine to loosen the four bolts “K”, Figure 2.24. DO NOT remove these four bolts.

2. Index to the required setting.

3. Lock the four bolts “K” to 47 lb-ft.

Move Ram Slide:

1. Use wrench provided with machine to loosen bolts “L” and “M”, Figure 2.25.

2. Use wrench to move the slide to the desired position using bolt “N”.

3. Tighten bolts “L” and “M”, starting with the rear bolt.

4. It is recommended that on heavy milling work, head should be kept as close to column as possible, where maximum rigidity is obtained.

Saddle Clamping:

1. When milling with longitudinal table feed only, it is advisable to clamp the knee to the column (see Figure 2.27) and the saddle to the knee to add rigidity to these members and provide for heavier cuts with a minimum of vibration.

2. The saddle locking lever is located on the left hand side of the saddle.

3. Excessive moisture can cause slight table bind.

4. Use moderate clamping pressure, as this will hold saddle sufficiently.

Bridgeport 2 26 27.png

Knee Clamping: The knee clamping levers are at the left side of the knee and front of knee. Leave clamped at all times unless using knee in operation (see Figure 2.27).

Table Clamping: The table clamp levers are located on front of saddle and should always be clamped when longitudinal movement is not required (see Figure 2.28).

Bridgeport 2 28.png

                                                    POWER FEED CONTROLS

Variable Table Feeds - Power Feed (X-Axis) Table

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Quick-Release Safety Handle - Grip handle and turn to either left or right until spring loaded plunger engages in position.

Variable Cross Slide Feed - Cross Feed Power Feed (Y-Axis)

                                                    E-HEAD CONTROLS

Head Swivel:

1. Loosen the four locknuts (see Figure 2.32). Support unit to prevent free fall.

2. Swivel to required angular setting.

3. Tighten the four locknuts first to 25 lb-ft. Then 50 lb-ft.

4. Remove the screw sealing vent hole before operating machine.

Bridgeport 2 31 32.png

To Change Speed:

1. Disconnect power from head.

2. Loosen the two motor locknuts (see Figure 2.33).

3. Slide motor forward.

4. Position vee belt on appropriate pulleys.

5. Slide motor to rear to tension vee belt.

6. Tighten the two motor locknuts.

7. With 50 cycle 1425 rpm 60, 85, 120, 170, 245, 350 strokes per minute.

Bridgeport 2 33 34.png

To Change Stroke

1. Loosen locknut (see Figure 2.34).

2. Turn stroke dial to required setting.

3. Press dial home to engage pin.

4. Tighten locknut.

5. Before operating attachment, ensure locknut is tight.

Clapper Box - To Swivel Clapper Box:

1. Loosen the two set screws “O”, Figure 2.35.

2. Rotate to the required angular setting.

3. Tighten the two set screws “O”.

Tool Relief

1. Loosen set screw “P”.

2. The tool will now have automatic relief on the return stroke.

Bridgeport 2 35.png



                                                       END OF THE PROCEDURE