Acme Gridley

Acme Gridley Image The following lesson outline details the tasks needed to be a machinist on an Acme Gridley automatic bar machine. Some of these tasks require the trainee to explain how something works to insure they have the required understanding of the processes and are not simply memorizing procedures. All of the tasks listed will be a part of the Performance Test within each lesson. To learn more about these tests and the training process itself, see the Philosophy section.

This training system was specifically designed to accommodate the various stock size Acme-Gridley machines commonly found in use today. The tasks are taught in a sequence that enables trainees to quickly become productive. For example, the trainee begins by learning the operating controls and how to restocking the machine. Later lessons explain the setup tasks in a logical order of progression.

Lesson 1: Basic Controls and Operations [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify by name, and explain the purpose for each of the major components of the machine including:
    1. Main Power Switch
    2. Main Control Station
    3. Auxiliary Control Station
    4. Take Control Switch
    5. Main Motor Switch
    6. Feed On and Off Controls
    7. Cross Slides
    8. Center Tool Slide
    9. Auxiliary Operating Lever
    10. Threading Slides & Pushers
    11. Cutting Positions
    12. Spindles
    13. Spindle Drum
    14. Chip Conveyor and Controls
    15. Hand Crank
    16. Coolant Pump Control
    17. Lubricating Oil Sight Gauge & Dip Stick
    18. Air Regulator and Gauge
    19. High Speed Clutch Lever
  2. Identify the sequence of events in the machining cycle. The following is included:
    1. Indexing
    2. Approach
    3. Feed Portion
    4. High Point or Dwell
    5. Feed Control
    6. Drawback
  3. Start the machine when ready for normal machining operation.
  4. Stop the machine during normal machining operation.
  5. Start the spindles and correctly use the hand crank to move the machine both forward and reverse.

Lesson 2: Stock Feed System [ Top ]

After completing this lesson the operator will be able to:

  1. Locate and explain the purpose for the following stock feed system components
    1. Stock Tubes
    2. Stock Reel
    3. Stock Feed Slide
    4. Stock Feed Cams
    5. Collets
    6. Pushers
    7. Feed Fingers
    8. Feed Tube
    9. Pusher Spool
    10. Guide Bushing
    11. Stock Stop
  2. Explain the sequence of events in the stock feeding cycle. The following steps are included:
    1. Indexing to the Feeding Position
    2. Collet Opening Cam Operation
    3. Feeding of stock
    4. Stock Feed cam operation
    5. Collet closing
    6. Pusher retraction

Lesson 3: Removal and Replacement of Pushers and Restocking [ Top ]

After completing this lesson the operator will be able to:

  1. Remove the Pusher assemblies.
  2. Remove the Feed Fingers.
  3. Select, clean, and install new Feed Fingers.
  4. Replace and secure the Pusher assembly.
  5. Locate, identify, and explain the features of solid and master Feed Fingers.
  6. Properly adjust the gripping pressure of cage-type Feed Fingers.
  7. Locate and select the correct bar stock as called for in the setup documentation.
  8. Properly measure bar stock diameter.
  9. Properly deburr bar stock ends.
  10. Properly align non-round bar stock with pusher and collet.
  11. Clean and load bar stock into the machine and position the bar end within the collet.

Lesson 4: The Collet Locking System [ Top ]

After completing this lesson the operator will be able to:

  1. Name, locate, and state the purpose of the following components in the collet locking system:
    1. Collet
    2. Collet Tube
    3. Collet Lever Body
    4. Collet Hand Operating Lever
    5. Collet Tension Adjusting Nut
    6. Collet Tension Adjusting Nut Locking Pin
    7. Spindle Alignment Pin
    8. Collet Keyway
    9. Collet Spacers
    10. Collet Alignment Disk
    11. Collet Slide
  2. Identify the situations in which collets must be changed including:

    1. Changes in stock size
    2. Cracked collets
    3. Worn collets
    4. Broken collets
  3. Correctly use the collet hand operating lever to open and close the collet and identify correctly adjusted collet tension.
  4. Remove the collet assembly from the spindle and clean the spindle and collet assembly.
  5. Clean and install either solid or master collets.
  6. Reinstall the collet assembly.
  7. Replace bar stock and properly adjust collet tension.
  8. Secure the collet tension adjusting nut.

Lesson 5: Setting Feed, Speed, and Stroke [ Top ]

After completing this lesson the operator will be able to:

  1. Identify and explain the purpose for each of the following:

    1. Positive Stop Screw
    2. Compensating Screw
    3. Drum Cams
    4. Disk Cams
    5. Lead Cam
    6. Guard Cam
    7. The Rise of a Cam
    8. The Approach of a Cam
    9. The Feed of a Cam
    10. The Dwell of a Cam
    11. Feed Range Gears
    12. Spindle Range Gears
    13. Feed Change Gears
    14. Spindle Change Gears
  2. Given the setup information, remove and replace the coarse and fine spindle speed and feed gears.
  3. Given the setup information, properly change the cross slide and center tool slide cams.

Lesson 6: Setting Stock Feed, Stock Stop, and Cutoff [ Top ]

After completing this lesson the operator will be able to:

  1. Explain the cutoff operation.
  2. Explain above-center and below-center cutoff conditions.
  3. Properly mount a cutoff blade into the cutoff tool holder.
  4. Mount the cutoff tool holder to the cross slide.
  5. Correctly align the cutoff holder to the spindle face based on workpiece dimensions and clearances required for other tooling in the setup.
  6. Center the cutoff tool to the spindle centerline.
  7. From the setup documentation, find the part length required.
  8. Measure and calculate the amount of stock feed required.
  9. Hand crank or jog the Stock Stop into position.
  10. Loosen and adjust the Stock Stop to the correct dimension for the part required.
  11. Hand crank or jog to enable Stock Feed Cam to be removed and replaced.
  12. Loosen and back off Pusher Guard Disk.
  13. Jog to retracted position of Stock Feed Slide and set the Pusher Guard Disk position and secure.

Lesson 7: Identification and Setting of Basic Tooling [ Top ]

After completing this lesson the operator will be able to:

  1. Identify and explain the purpose for the basic tools and their holders used in the screw machine:
    1. Screw Machine Drill
    2. Fast Spiral Drill
    3. Chip Breaker Drill
    4. Tapered Shank Drill
    5. Spot Drill
    6. Drill Holder
    7. Floating Holder
    8. Dove Tail Form Tool
    9. Dove Tail Form Tool Holder
  2. Explain the purpose of properly setting Positive Stop tension.
  3. Based on setup documentation, correctly select the tools for the job.
  4. Clean, mount and center a roughing form tool.
  5. Jog to high-point of the cross slide cam and set depth of cut.
  6. Properly adjust Positive Stop tension for the cross slide form tool.
  7. Clean, mount, and adjust a finishing form tool.
  8. Jog to high-point of the cam and set depth of cut for a finishing form tool.
  9. Adjust Positive Stop tension on the cross slide with a finishing tool.
  10. Clean, mount, and adjust a drill on the Center Tool Slide.
  11. Jog to high point of the cam and set depth of cut for Center Tool Slide mounted fixed tooling.
  12. Set Positive Stop tension for the Center Tool Slide.
  13. Adjust coolant lines properly.

Lesson 8: Controlling the Quality of Parts [ Top ]

After completing this lesson the operator will be able to explain:

  1. Given workpieces with and without chatter marks, be able to recognize those with chatter.
  2. Explain the 10 most common causes of chatter in the screw machine while using the Job Aid contained within the lesson.
  3. Explain how to correct the 10 most common causes of chatter in the screw machine while using the Job Aid contained within the lesson.
  4. Explain the 4 most common causes of short feed in the screw machine when only some of the parts produced are short.
  5. Explain the corrective action to use for each of the 4 common causes of short feed when only some of the parts produced are short.
  6. Explain the 7 most common causes of short feed in the screw machine when all of the parts produced are short.
  7. Explain the corrective action to use for each of the 7 common causes of short feed when all of the parts produced are short.
  8. Correctly identify a worn, damaged or dull drill.
  9. Measure and remove a drill.
  10. Correctly sharpen a drill, then measure cutting surfaces and drill-point angles.
  11. Correctly replace a drill to the previous depth of cut.
  12. Correctly identify a worn, damaged, or dull form tool.
  13. Remove a form tool.
  14. Correctly sharpen a form tool, and measure for squareness and proper rake and relief angles.
  15. Hone a newly sharpened form tool.
  16. Reinstall and center a form tool.
  17. Identify a damaged, worn or dull cutoff blade.
  18. Correctly measure and remove a cutoff blade.
  19. Correctly sharpen and measure rake and relief angles on a cutoff blade.
  20. Correctly replace a cutoff blade.

Lesson 9: The Recessing Attachment [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a recessing attachment and it's operating sequence and component parts.
  2. Properly clean the attachment and mounting slide.
  3. Properly mounting the attachment to the slide.
  4. Properly connect the attachment to the operating mechanism.
  5. Properly mount and center the recessing tool in the attachment.
  6. Move the machine to high point and adjust for tool entry clearance.
  7. Adjust for the proper location of cut within the workpiece.
  8. Adjust for proper depth of cut within the workpiece.
  9. Explain the use of the attachment gib to reduce chatter.

Lesson 10: The Accelerated Reaming Attachment [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a reaming attachment and it's operating sequence and component parts.
  2. Properly clean the attachment and auxiliary slide.
  3. Properly mount the auxiliary slide to the machine.
  4. Mount the attachment to the auxiliary slide.
  5. Connect the operating mechanism and set the throw ratio required.
  6. Properly mount and secure the floating holder and reamer into the attachment.
  7. Mount the correct feed and guard cam.
  8. Measure and adjust for proper depth of ream.

Lesson 11: The Shaving Attachment [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a shaving attachment and it's operating sequence and component parts.
  2. Explain the shave tool machining cycle.
  3. Clean and mount the shave tool in the shave tool holder.
  4. Preset the depth of the shave cut to meet setup requirements.
  5. Clean the cross slide and mount the shave tool attachment to the slide.
  6. Back off positive stop and the cross slide to eliminate contact at high point.
  7. Jog or hand crank the machine to high point.
  8. Align the shave tool attachment to the formed workpiece and secure to the slide.
  9. Adjust attachment vertically until roller contacts workpiece, then secure.
  10. Adjust cross slide forward past centerline of part and secure cross slide.
  11. Identify and correct for taper.

Lesson 12: Tapping Operations [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a tapping attachment and it's operating sequence and component parts.
  2. Check operation of and clean components of the universal threading attachment and die slide.
  3. Mount the attachment to the die slide.
  4. Connect drive shaft and push bar to attachment.
  5. Jog machine to beginning of feed and mount kicker cam.
  6. Move attachment forward, set depth of tap undersize with adjusting nuts.

Lesson 13: Die Head Threading [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a Die Head Threading attachment and it's operating sequence and component parts.
  2. Clean and mount the preset die head and yoke to the threading spindle of the attachment.
  3. Jog the machine to the beginning of the feed.
  4. Mount the kicker cam.
  5. Adjust pusher bar to compress starter spring.
  6. Jog machine to near end of thread.
  7. Set yoke to open die before end of thread.
  8. Jog to return and set jam nuts to close die head.
  9. Thread workpiece and adjust for correct thread length and depth, and die head closing.

Lesson 14: Thread Rolling [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a thread rolling attachment and it's operating sequence and component parts.
  2. Check all thread roll components against setup documents.
  3. Clean and assemble rolls, drive gears and thrust bearings in head.
  4. Using the correct gauges, set roll gap and arm position.
  5. Check each arm is parallel.
  6. Set rough roll match.
  7. Set fine roll match.
  8. Mount thread roll cam to cross slide cam drum.
  9. Position gauge to set correct dimension.
  10. Adjusted slide forward until positioning gauge contacts workpiece, then secured.
  11. Run workpiece and adjust for full thread depth and dimension.

Lesson 15: The Pick-Off Attachment [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify, and explain a pick-off attachment and it's operating sequence and component parts.
  2. Remove the cut-off tool and back machining tool which may be installed.
  3. Disconnect back pressure spring and set the preliminary stroke of the operating arm.
  4. Manually open pick-off collet and remove collet.
  5. Remove and replace ejector collet assembly.
  6. Install pick-off collet assembly and set tension with sample workpiece.
  7. Set the timing of the closing of the pick-off collet and set positive stop.
  8. Install and set the cut-off tool.
  9. Jog through the cycle to cut-off and pick-off the workpiece.
  10. Mount the back machining tool, set machining depth and set positive stop tension.
  11. Set pick-off collet opening.
  12. Install and set ejector stop-rod at withdraw.
  13. Synchronize pick-off collet to work collet for hex or square stock, if required.