Chapter 9 Part 5: Manual Vertical Milling Machines

FACE MILLING

What is it?

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A face mill is positioned above a block that has been faced. The face mill is in a milling spindle and the block is secured in a milling vise on the table./ Photo Credit: Micky R. Jennings, CC-BY 4.0

 

Face milling , or facing, is the process of establishing an accurate surface of the part. This surface will be used as a reference for other feature depths. For that reason, it is often the first operation performed on raw material on a milling machine.

Step by step process for face milling:

  1. Load a face mill into the milling machine.
  2. Load a piece of material into a mill vise and onto a pair of parallels, and tighten the handle.
  3. Gently tap the part downward with a dead blow hammer to seat the part securely on at least one of the parallels.
  4. Apply some layout dye to the top of the part.
  5. Calculate a spindle speed based on the SFPM and the diameter of the tool.
  6. Calculate a feed rate based on the finish requirement of the part. CPT selection for a face mill is different than that of an end mill because the face mill can often handle larger CPT than will look good for a surface finish. As small as .003 or as large as .030 or more could be used, depending on finished part surface requirements.
  7. Pull the quill handle down about 1/2” and lock the quill in place. The quill should always be locked for sideways milling operations, regardless of where the position is.
  8. Move the table, saddle and knee to where the tool is just above the part by about 1/2” and centered by the saddle movement. Lock the saddle.
  9. Put the machine into low or high gear range.
  10. Turn on the spindle
  11. Adjust the speed.
  12. Slowly move the knee up until the inserts of the face mill just remove the layout dye.
  13. Zero the knee graduated collar.
  14. With the table movement, move the part out from under the face mill.
  15. Using the knee, set a depth of cut.
  16. Using the table hand wheel or the powered unit, move the part underneath and past the work at the calculated feed rate.
  17. Turn off the spindle.
  18. Inspect for fully milled surface and/or thickness of part, and repeat if necessary.
  19. Remove tool from spindle by holding brake with left hand and loosening draw bar with right hand.
  20. Once loose, place the left hand under the tool and further unscrew the draw bar one full turn by hand. Only one full turn!
  21. With a rag in the left hand, cradle the tool and tap on the top of the draw bar to release the machine taper. If the draw bar is fully unscrewed when the opperator attempts to tap the tool out of the spindle, the last thread of the tool and draw bar will become damaged and broken over time.
  22. Clean the face mill and return it to the storage area.

“Step 1: Load a face mill into the milling machine.“

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A hand holds a face mill./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 1: Load a face mill into the milling machine.“

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A hand loads a face mill into a milling spindle./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 4: Apply some layout dye to the top of the part.“

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A hand applies layout dye to the top of a block that is secured in a milling vise./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 7: Pull the quill handle down about 1/2” and lock the quill in place. The quill should always be locked for sideways milling operations, regardless of where the position is.“

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A hand locks the quill of the milling machine in preparation for face milling./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 8: Move the table, saddle and knee to where the tool is just above the part by about 1/2” and centered by the saddle movement. Lock the saddle.“

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A side view of the face mill cutting operation and its coverage of the part./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 8: Move the table, saddle and knee to where the tool is just above the part by about 1/2” and centered by the saddle movement. Lock the saddle.“

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A hand locks the saddle in place in preparation for face milling./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 10: Turn on the spindle“

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A hand reaches for the spindle power switch./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 11: Adjust the speed.“

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A hand reaches for the spindle power switch./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 15: Using the knee, set a depth of cut.“

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Setting the depth of cut by raising the knee by .02./ Photo Credit: Micky R. Jennings, CC-BY 4.0

Block Squaring

What is it?

Block Squaring is the process of performing face milling operations on each side of a block in a specific manner that transfers the precision of the mill vise into angular accuracy on the part. Each of the six sides of a rectangular block will be machined, creating the outer envelope of the overall size of the finished part.

Step by step process for block squaring:

  1. Side one
    1. Load a face mill into the spindle.
    2. Load a rectangular block of material into a milling vise with the largest side in preparation to be faced.
    3. Place the part on parallels.
    4. Take a 1/64” to 1/32” facing cut to clean the surface.
    5. Remove the part and deburr all edges.
  2. Side two
    1. Load the block of material back into the milling vise, with side one against the solid jaw and the second largest side in preparation to be faced.
    2. Place the part on a single parallel.
    3. Use a round bar in between the movable jaw and the part when clamping.
    4. The reason for the bar and the single parallel is to make sure the part conforms to sitting flat against the solid jaw plate and not the movable jaw plate or a pair of parallels.
    5. Take a 1/64” to 1/32” facing cut to clean the surface.
    6. Remove the part and deburr all edges.
  3. Side three
    1. Load the block of material back into the milling vise, with side one against the solid jaw and side two against the single parallel.
    2. Use a round bar in between the movable jaw and the part when clamping.
    3. Tap the part down tight against the parallel.
    4. Take appropriate roughing and finishing facing cuts to bring the part to size.
    5. Remove the part and deburr all edges.
  4. Side four
    1. Load the block of material back into the milling vise, with side one against a pair of parallels and side two against the solid jaw.
    2. Do not use a round bar.
    3. Tap the part down tight against the parallels.
    4. Take appropriate roughing and finishing facing cuts to bring the part to size.
    5. Remove the part and deburr all edges.
  5. Side five
    1. Load the block of material back into the milling vise, with side one against the solid jaw and the third largest side in preparation to be faced.
    2. Place the part on a single parallel.
    3. Use a round bar in between the movable jaw and the part when clamping.
    4. Clamp gently.
    5. Use an indicator to dial the side of the part straight up and down. Tap it with a hammer to move it slightly.
    6. Fully tighten the vise.
    7. Take a 1/64” to 1/32” facing cut to clean the surface.
    8. Remove the part and deburr all edges.
  6. Side six
    1. Load the block of material back into the milling vise, with side one against the solid jaw and side five against the single parallel.
    2. Use a round bar in between the movable jaw and the part when clamping.
    3. Tap the part down tight against the parallel.
    4. Take appropriate roughing and finishing facing cuts to bring the part to size.
    5. Remove the part and deburr all edges.

“Step 1-5: Remove the part and deburr all edges.“

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A hand holds a part as a file is pushed against one edge of a freshly faced side./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 1-5: Remove the part and deburr all edges.“

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A hand holds a block that has had the first side faced and deburred./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 2-3: Use a round bar in between the movable jaw and the part when clamping.“

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A hand holds a round bar horizontally to make contact with the part on the movable vise jaw side./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 2-3: Use a round bar in between the movable jaw and the part when clamping.“

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A side view of a round bar being used on the movable jaw side of a mill vise./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 2-6: Remove the part and deburr all edges.“

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A hand holds a block that has had the first and second sides faced and deburred./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 3-4: Take appropriate roughing and finishing facing cuts to bring the part to size.“

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A hand uses a pair of calipers to measure the width after the third cut. The part is being measured while still secure in the vise to keep from disturbing the setup./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 3-4: Take appropriate roughing and finishing facing cuts to bring the part to size.“

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A side view of calipers measuring the width after the third cut. The part is being measured while still secure in the vise to keep from disturbing the setup./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 4-4: Take appropriate roughing and finishing facing cuts to bring the part to size.“

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Side four has been faced and is still in the vise ready for thickness measurement./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 5-3: Use a round bar in between the movable jaw and the part when clamping. “

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The block is placed in the vise on parallels with side one against the solid jaw and side five facing up. A round rod is used against the movable jaw./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 5-5: Use an indicator to dial the side of the part straight up and down. Tap it with a hammer to move it slightly.“

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An indicator is used on side two or three to adjust the vertical placement of the block for the facing of the fifth side./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 5-9: Remove the part and deburr all edges.“

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A hand holds a block that has had five sides faced and deburred./ Photo Credit: Micky R. Jennings, CC-BY 4.0

“Step 6-4- Take appropriate roughing and finishing facing cuts to bring the part to size.“

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Side six has been faced and is still in the vise ready for length measurement./ Photo Credit: Micky R. Jennings, CC-BY 4.0

Alternative side five and six steps for block squaring:

  1. Side five alternate
    1. Load a large end mill into the spindle.
    2. Load the block of material back into the milling vise, with side one against a pair of parallels and side two against the solid jaw. Let side five overhang the side of the vise.
    3. Tap the part down tight against the parallels.
    4. Take 1/64” to 1/32” material off using end mill side passes to clean the surface. One rough, one finish.
    5. Remove the part and deburr all edges.
  2. Side six alternate
    1. Load the block of material back into the milling vise, with side one against a pair of parallels and side two against the solid jaw. Let side six overhang the side of the vise.
    2. Tap the part down tight against the parallels.
    3. Take appropriate roughing and finishing side cuts to bring the part to size.
    4. Remove the part and deburr all edges.

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