1. Milling Machine Setups
Unit 66

2. Objectives Mount and remove a milling machine arbor
Mount and remove a milling cutter
Align the milling machine table and vise

3. Milling Machine Safety
Be sure work and cutter are mounted securely before taking cut
Always wear safety glasses
When mounting or removing milling cutters, always hold them with cloth to avoid being cut
When setting up work, move table as far as possible from cutter to avoid cutting your hands

4. Be sure cutter and machine parts clear work
Never attempt to mount, measure, or adjust work until cutter completely stopped
Keep hands, brushes, and rags away from revolving milling cutter at all times
Do not use an excessively heavy cut or feed
Cause cutter to break and fly apart

5. Never reach over or near revolving cutter
Always use brush, not rag, to remove cuttings after cutter has stopped revolving
Never reach over or near revolving cutter
Keep hands at least 12 in from revolving cutter
Keep floor around machine free from chips, oil, and cutting fluid

6. Milling Machine Setups
Check if machine surface and accessory free from dirt and chips prior to mounting
Do not place tools, cutters, or parts on milling machine table
Use keys on all but slitting saws when mounting cutters

7. Check that arbor spacers and bushings clean and free from burrs
When tightening arbor nut, take care to only hand tighten
Hammer or wrench will strip threads and bend or damage accessory or part
When mounting work in vise, tighten vise securely by hand and tap into place with lead or soft-faced hammer

8. Milling Hints Treat milling cutters with care to prevent damage
Always examine condition of milling cutter cutting edges before use
Replace if necessary, never use dull cutters
Use correct speeds and feeds for size of cutter and type of material to be cut
For maximum cutter life, use lower cutting speeds and increase feed rate

9. Mount end mills as short as possible to prevent breakage
Position arbor supports as close as possible to milling cutters for maximum rigidity
Climb mill wherever possible
Permits use of higher speeds and improves surface finish
Must have backlash eliminator for climb milling
Always direct cutting force toward solid part of machine, vise, or fixture

10. Use coarse tooth cutters for roughing cuts
Make sure milling cutter rotating in proper direction for cutting action of teeth
Use coarse tooth cutters for roughing cuts
Provide better chip clearance
Stop machine whenever there is discoloration of chips
Indicates poor cutting action
Use good supply of cutting fluid for all milling operations
Prolongs life of cutter

11. Milling Arbor Used to hold cutter during machine operation
Must follow proper procedure of mounting or removing arbor to preserve accuracy of machine
May damage taper surfaces of arbor or machine spindle
Cause arbor to bend
Make cutter run out of true

12. The Arbor Assembly
Milling cutter driven by key that fits into keyways on arbor and cutter
Prevents cutter from turning on arbor
Spacer and bearing bushing hole cutter in position
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

13. Draw-in bar holds arbor firmly in place in the spindle
Tapered end of arbor held securely in machine spindle by draw-in bar
Outer end of arbor assembly supported by bearing bushing and arbor support
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

14. To Mount an Arbor
Clean tapered hole in spindle and taper on arbor using clean cloth
Check for cuttings or burrs in taper
Check bearing bushing and remove any burrs
Place tapered end of arbor in spindle and align spindle driving lugs with arbor slots
Place right hand on draw-in bar and turn thread into arbor approximately 1 in.
Tighten draw-in bar lock nut securely against back of spindle

15. To Remove an Arbor Remove milling machine cutter
Loosen lock nut on draw-in bar (2 turns)
With soft-faced hammer, sharply strike end of draw-in bar until arbor taper is free
With one hand, hold arbor; unscrew draw-in bar from arbor with other hand

16. Carefully remove arbor from tapered spindle to avoid damage to spindle or arbor tapers
Leave draw-in bar in spindle for further use
Store arbor in suitable rack to prevent being damaged or bent

17. To Mount a Milling Cutter
Remove arbor nut and collar and place them on piece of masonite
Clean all spacing collar surfaces of cuttings and burrs
Set machine to slowest spindle speed
Check direction of arbor rotation by starting and stopping machine spindle
Slide spacing collars on arbor to position desired for cutter

18. Fit key into arbor keyway at position where cutter is to be located
Hold cutter with cloth and mount it on arbor
Cutter teeth point in direction of arbor rotation
Slide arbor support in place and check that bearing bushing on arbor
Put on additional spacers, leaving room for arbor nut (tighten nut by hand)

19. Lock arbor support in position
Tighten arbor nut firmly with wrench, using only hand pressure
Lubricate bearing collar in arbor support
Make sure arbor and arbor support will clear the work

20. To Remove a Milling Cutter
Be sure arbor support is in place and supporting arbor on bearing bushing before using wrench on arbor nut
Clean all cuttings from arbor and cutter
Set machine to lowest spindle speed
Loosen arbor nut with properly fitting wrench (threads left-hand)

21. Loosen arbor support and remove it from overarm
Remove nut, spacers, and cutter
Clean spacer and nut surfaces and replace them on arbor
Do NOT use wrench to tighten arbor nut at this time
Store cutter in proper place to prevent cutting edges from being damaged

22. Procedure for Aligning Table on Universal Milling Machine
Clean table and face of column thoroughly
Mount dial indicator on table by means of magnetic base or any suitable mounting device
Move table toward column until dial indicator registers approximately one-quarter of a revolution

23. Set indicator bezel to zero by turning dial
Using table feed handwheel, move table along width of the column
Note reading on dial indicator and compare to zero reading at other end of column
If any movement of indicator hand, loosen locking nuts on swivel table housing

24. Adjust table for half difference of needle movement and lock table housing
Recheck table for alignment and adjust until there is no movement in indicator as it is moved along column
Note: Always indicate from the table to the face of the column, never from the column to the table.

25. To Align Vise Parallel to the Table Travel
Clean surface of table and base of vise
Mount and fasten vise on table
Swivel vise until solid jaw approximately parallel with table slots
Mount indicator on arbor or cutter
Make sure solid jaw is clean and free from burrs

26. Move table along for length of parallel and note reading of indicator
Adjust table until indicator registers about one-quarter of a revolution against parallel held between jaws of vise
Set bezel to zero
Move table along for length of parallel and note reading of indicator
Compare to zero reading at other end of parallel
Loosen nuts on upper or swivel part of vise

27. Adjust vise to half the difference of indicator readings by tapping it with your hand or with soft-faced hammer in appropriate direction.
Note: Never tap the vise so the parallel moves against the indicator plunger
Recheck vise for alignment and adjust, if necessary, until no movement in indicator as moved along parallel