Machine Tools

Overview

Users should familiarize themselves with the machine tools safety rules and procedures.
 

Lathe Safety Rules

1. ALWAYS wear safety glasses/goggles.
2. When stopping the lathe, NEVER use your hand to slow down the chuck.
3. ALWAYS remove the chuck key from the chuck immediately after use.
4. Use the proper speed and feed rate for the job at hand.
5. Use the proper tool for the operation.
6. Before applying power make sure the cross-slide table and tool holder will clear the rotating chuck.
7. Fasten the tool bit as close to the tool holder as possible to prevent chatter or breakage.
8. DO NOT wear long sleeves, ties, or rings. Hoodie strings must always be tucked in.
9. DO NOT handle turning chips with your fingers.
    

Milling Machine Safety Rules

1. Safety glasses are required anytime a mill is running in the shop.
2. The mill’s principle danger is its sharp, rotating cutters, which can cut you even when they are not moving.
3. All measurements will be performed with the cutter stationary.
4. We do not use ‘mill guards’ because they simply are not practical.
5. No gloves or rags will be used while working on the mill.  Also, do not move your face too close to the work due to flying chips.
6. Always use a brush to remove chips or apply any cutting fluid.
7. Project materials must always be held properly in the mill – vise, clamps, and hold downs.
8. Ask one of the university machinists to change the cutters as necessary.
9. Use the six-jaw chuck to secure any round stock to be milled.
10. When running a program:
    a. always override the speed down to 20 or 30% to avoid crashing the cutter. Ramp back up to full speed after the program is running correctly.
    b. be aware of the quill handle movement, especially during drilling operations so as to not be struck.  Adjust the handle position as necessary.
    c. remember to fold in X and Y handles to avoid being caught-up when the tables are moving.
    d. always remain near the mill when it is in operation.
     

Introduction to the Lathe

The operation performed on the lathe is called “turning.”  Its primary use is to turn round parts or features.  On the lathe the part is spinning and the bit is stationary.

Parts of the Lathe: Bed, Ways, Headstock, Tailstock, Carriage, Chuck, Tool-post

Starting the Lathe.

Turning  Speed and Feed Rates.

The cutting tool depends on the type of operation you are performing, usually it will be some type of lathe bit.  Lathe bits are normally single point cutters.

Setup of cutter: Cutter on centerline with point ahead of the rest of the tool.

The method of holding parts in the lathe is determined by the operation, and to some extent, the part being machined. Holding methods include: Collets, Three, Four, or Six Jaw Chuck to hold on the O.D or I.D., Turning between centers, Bolting parts to a Mandrel or Face Plate.

Operations on the Lathe:

• Facing – Cutting across the face of the part
• Turning – Cutting along the axis of the part
• Tapering – Cutting an angle or bevel
• Threading – Cutting a helix around the periphery of the part; an integration of the X and Z axis
• Drilling - Usually done on center in the lathe
• Boring – Cutting inside the part
• Knurling – Pressing a raised feature into the part
• Filing – Done to break the edge of a part or to deburr
• Polishing – Used to fit the part or to deburr
• Parting – Separating a finished part by using a straight cutting tool
   

Milling Operation Notes

Mills – Bed and Knee, Vertical and Horizontal

Mill Parts

• Vises – Standard square jaw &  6 Jaw Chuck – clamp-on stop for multiple parts
• Tables – X-Y Axis – T-Slots for clamping
• Head – Z Axis – Quill & handle – Draw Bar, Uses Tapered Spindles for tooling
• DRO – X, Y, Z positioning, Fill-in-the-blanks Programming

Note: Always remember to disengage Jog Function before zeroing any Axis.

Mill Operations

• Milling – Roughing, 4 flute for steel, 2 flute for aluminum
• Conventional – milling material against the direction of the cutter
• Climb – milling material with the direction of the cutter

Note: Steel or Stainless must only be conventionally milled – climb milling steel tends to grab the material and pull it out of the vise.

• Form cutting – Round-over, Chamfering, Ball mill for rounded pockets
• Fly Cutting – Single point cutter for wide facing with a single pass
• Indexable Cutter – Replaceable carbide inserts for tough materials
• Drilling – Using standard drill chuck (also used for manual thread tapping