Vertical Milling / Cutting Tools

Positive Rake Angles

Angles produce a good surface finish, increase cutter life, and use less power in cutting. Are effective in machining tough and work-hardened materials.

Base and Column

Are one piece and are the major structural components of a vertical mill.

Solid Holder

Are the most widely used on vertical milling machines. Is more rigid and holds tools more securely than a collet holder. Has a precision-ground shank that fits the spindle on the milling machine.

Face Mills

Are used when flat surfaces have to be produced. Are designed lighter-duty cutters for finishing cuts or heavy-duty cutters with fewer teeth and heavier bodies for roughing operations.

Cutting Speed Rule

As a rule, lower cutting speeds are used to machine hard or tough materials or when heavy cuts are taken, and it is desirable to minimize tool wear and to extend tool life. Higher cutting speeds are used in machining softer materials to achieve better surface finishes. Higher speeds also apply when using small-diameter cutters for light cuts on fragile workpieces and in delicate setups.

Depth of Cut Rule

As a rule, the depth of cut for an end mill should not exceed half the diameter of the tool in steel. With roughing end mills, the depth of cut can be as much as one and a half times the cutter diameter and the width of cut half the cutter diameter.

Spiral-fluted taps

Brings the chips up and out of the hole.

Boring

Can produce holes of any size with a good finish and can locate them very accurately.

Edge Finder

Consists of a shank with a floating tip that is retained by an internal spring. Is accurately machined to a known diameter, usually .200 or .500 inch. Continue to slowly advance the workpiece against the edge finder tip until the tip runs perfectly true and then suddenly moves sideways. If you are using a .200-inch-diameter tip, the centerline of the spindle is .100 inch from the edge of the workpiece.

Negative Rake Angels

Create high cutting pressures, which tend to force the workpiece away from the cutter. Negative-rake inserts should not be used on work-hardened materials or ductile materials such as aluminum or copper.

RPM = (CS x 4)/D RPM = revolutions per minute of the cutter CS = cutting speed of the material being machined, in feet per minute D = diameter of the cutter, in inches

Cutting Speed Formula

Quill Feed Selector

Different quill feed rates, usually .0015, .003, and .006 inch per spindle revolution, are selected with the

Feed Rate Formula

IPM = F x N x RPM IPM = feed rate, in inches per minute F = feed per tooth, in inches N = number of teeth on the cutter being used RPM = revolutions per minute of the cutter.

Three-flute End Mills

Is a compromise between the bigger chip capacity of a two flute and the better finishing ability of the four-flute end mill. Is an excellent choice for slotting. Gives an acceptable surface finish. Much of the time, two of the three teeth are in the cut, giving a smooth, chatterless cutting action.

Split Collet

Is also used to hold cutters. When the tapered part of the collet is pulled into the spindle taper by the drawbolt, the split in the collet permits it to squeeze tightly against the shank of the end mill. Are effective cutter-holding devices, it is possible for a cutter to be pulled from the collet because of heavy feed rates or a dull cutting tool.

Gun Tap

Is especially useful for tapping holes that go through the workpiece.

Cutting Fluid

Is important in milling. A good cutting fluid absorbs heat generated in cutting and provides a lubricant between the chips and the cutting tool. Cutting fluid should be applied where the cutting is taking place, and it should flood the cutting area.

Lead Angle

Is the angle of the cutting edge measured from the periphery of the cutter, varies from 0 to 45 degrees, depending on the application.

Base and Column, Knee, Saddle, Table, Ram, and Toolhead.

Major Assembles of the Vertical Milling Machine

Knee, Saddle, Table, and Quill

Parts of vertical mill that are equipped with locks. During machining, all axes except the moving one should be locked. This will increase the rigidity of the setup.

Feed Control lever

Power feed to the quill is engaged by

A right-hand cutter will cut while turning in a counterclockwise direction. A left-hand cutter will cut while turning in a clockwise direction.

Right Hand vs. Left Hand Cutter

Center or Spotting Drills

These drills are short, stubby, and rigid and do not flex or deflect, as longer drills have a tendency to. Produces a small start point that is accurately located. When the hole is drilled, the drill point will follow the starting hole that the spot drill made. This method can produce holes that are reasonably accurate in location.

Twist Drill & Spade Drill

Two basic types of high-speed drills.

Direct Workpiece Mounting

Work that is too big or has an odd configuration can be bolted directly to the table. This method of work holding takes the most ingenuity and expertise. There are a number of accessories that can be used to aid the setup person.

Angle Plates

Work that needs to be held at a 90-degree angle to the table.

Micrometer Dial

allows depth stop adjustment in .001-inch increments.

Carbide End Mills

are designed to outperform HSS cutters, especially when machining abrasive materials. Are used primarily because they can dramatically improve productivity. If these mills are made from fine-grain carbide, their toughness approaches that of HSS with the hardness of carbide.

Twist Drill

are great for rapidly producing holes that do not have to be very accurate in size or position.

End Mills

are the most commonly used tool on a vertical milling machine. May have two, three, four, or more flutes and may be right- or left-hand cutting. To determine the cutting direction of an end mill, observe the cutter from its cutting end.

Fixtures

are tools that are designed to accurately position and hold a specific part. They are typically found in a production shop and can be built to hold one part or many parts.

Tapered End Mills

are used in mold making, die work, and pattern making, where precise tapered surfaces need to be machined.

Woodruff Key

are used to connect and drive shafts and pulleys.

Carbide-tipped twist Drills

basically carbon steel drills with a piece of tungsten carbide brazed into them. They look similar to a spade drill but are usually made in smaller diameters. Solid carbide drills are just that, a solid carbide cutting tool. Solid carbide drills are typically found in small diameters because of the cost of the carbide materials.

Two-flute End Mills

can be used for plunge cutting. These are called center cutting because they can be plunged into the work without a starting hole.

Conventional or Up Milling

direction of feed is opposed to the direction of rotation

Climb or Down Milling

direction of feed is the same as the direction of cutter rotation

Quill

does not rotate. Contains the rotating spindle. Can be extended and retracted into the toolhead by a quill feed hand lever or handwheel. The quill feed hand lever is used to rapidly position the quill or to drill holes. Some vertical mills have a quill feed handwheel. A quill feed handwheel provides a controlled, slow manual feed.

Knee

engages the slide on the face of the column and is moved up and down by turning the vertical traverse crank. Supports the saddle and table. Locks secure the at any position.

Saddle

engages the slide on the top of the knee and can be moved in and out by turning the saddle-traverse crank. Supports the table. Locks lock the saddle at any position.

Table

engages the slide on the top of the saddle and is moved right and left by turning the table traverse handle. The workpiece or work-holding device is secured to the table. Locks are provided so that the table may be locked at any position. Many milling machines have a power feed mechanism on the table. This enables the table to be fed at a variable feed rate in either direction.

Spade Drill

has a flat blade with sharp cutting edges. Is clamped in a holder and can be resharpened many times. Typically are used for drilling very large diameter holes.

Indexable End Mills

has largely replaced the use of HSS tools in industrial machining. A major advantage is the ability to select tool grades that are the best for a particular material. Other advantages are the availability of many cutter types. Do not require resharpening: you just replace the inserts.

Ball-end End Mills

have two or more flutes and form an inside radius (fillet) between surfaces. Are used in mold making and in diesinking operations. Round-bottom grooves can also be machined with them. Precise convex radii can be machined on the edge of parts with corner-rounding end mills

Cutting Speed

in milling is the rate at which a point on the cutter passes by a point on the workpiece in a given period of time.

Carbide Inset Drills

incorporate indexable or replaceable inserts and can remove metal four to ten times faster than an HSS drill.

High Helix Angle

is 40 degrees or more.

Reamer

is a cylindrical tool similar in appearance to the drill. Produce holes to a tight tolerance with a smooth finish.

Flycutter

is a single-point tool with a high-speed or carbide tool secured in a special holder. Are often used to take light face cuts from large surface areas.

Rotary Table

is a useful accessory for the milling machine. The rotating motion is controlled by a precision worm and worm gear assembly.

Dividing Head

is a useful milling machine accessory. It is used to rotate the workpiece a full or partial turn to machine a specific number of divisions, an angle, or a circular feature.

Toolhead

is attached to the end of the ram. The spindle motor is mounted on the toolhead. The spindle is turned on with a three-position switch (High Range/Off/Low Range). Be sure that the spindle is rotating in the proper direction when you turn on the spindle. Speed changes are made with V-belts, gears, or variable-speed drives.

Ram

is mounted on the slide on the top of the column. Is moved in and out by turning the ram positioning pinion gear. Movement can extend the head to increase the working area. Locks secure the ram position.

Slow Helix Angle

is one in which the helix angle of the cutter is about 12 degrees.

Vise

is the most common work-holding device. Is used for holding work with parallel sides and is bolted directly to the table using the T-slots in the machine table. This vise has a swivel so that the vise can be set at any angle.

Tapping

is the process of producing internal threads. There are many different types. The most common types of tap used on machines are the gun tap and the spiral-fluted tap.

Feed Rates

is the rate at which the cutter is advanced into the work material. Because each tooth of a milling cutter is cutting, a chip of a given thickness will be removed depending on the rate of feed. Chip thickness affects the life of the milling cutter. Excessive feed rates can cause a chipped cutting edge or a broken cutter. On the other hand, the highest practical feed rate per tooth will give the longest tool life.

Spindle Lock or Spindle Break

is used to keep the spindle from rotating when installing or removing tools. Tools are usually held in collets, which are secured in the spindle with a drawbolt. The drawbolt threads into the upper end of the collet. When the drawbolt is tightened, the collet is drawn into the taper in the spindle. This aligns and holds the tool.

Quill Clamp

is used to lock the quill in a fixed position. To obtain maximum rigidity while milling, you should tighten the quill clamp.

Roughing End Mill

is used when large amounts of material must be removed (roughed) quickly. These end mills are also called hogging end mills and have a wavy tooth form cut on their periphery. These wavy teeth form many individual cutting edges. The tip of each wave contacts the work and produces one short compact chip. Each succeeding wave tip is offset from the next one, which results in a relatively smooth surface finish.

Four-flute End Mills

may also be center cutting. However, if these are center drilled or gashed on the end, they cannot start their own holes. This type of end mill will cut only on its periphery.

Regular Helix Angle

may be 30 degrees