Chapter 14 study guide

What are the five ways of machining tapers on a lathe

-compound -offset tailstock -taper attachment -reamer -tool bit

A taper is isefull in machining technology because

-its wedging action permits it to drive cutting tools -it can be assembled and disassembled easily -it will automatically align a tool in a similar hole

Which of the two types of taper attachments requires disconnecting the cross-slide screw from the cross-slide nut

-plain taper attachment -telescopic taper attachment

A groove is cut at the point where the thread is to terminate and serves to

-provide a place to stop the threading tool after making a cut -permit a nut to run up to the end of the thread -end the thread

Cutting left hand threads requires

-that the carriage travels towards the tailstock -changing the lead screw rotation -pivoting the compound to the left

What is pitch equal to

1/ the # of threads per inch

At what spindle speed are screw threads cut

1/4th the speed thats used for conventional turning

The compound rest is set at to cut sharp threads

29°

On the thread the top and bottom are flat but the sides have a 29° included angle

Acme

What information must be known in order to cut a taper using a taper attachment

Angle Taper per foot Taper per inch

List advantages of a taper attachment

Can do internal and external

When cutting sharp v-threads a gage is used for grinding the cutter and setting it in position

Center

Tailstock offset can be determined visually by measuring the distance between the or betweem the witness lines on the base of the tailstock

Center points

Internal thread

Cut on inside surface of piece

External thread

Cut on outside diameter of piece

What is referred to as lead on a screw thread

Distance from one nut will travel in one complete revolution of a screw

Define pitch as it applies to thread terminology

Distance from one thread point to the next, measured parallel to thread axis

When cutting threads -profile inserts produce the best thread form and finish

Full

Pitch diameter

Imaginary diameter at the point where the widths of the thread and groove are equal

When cutting tapered threads to obtain a fluid or gas tight joint the threading tool must be positioned

In relation to the centerline of the taper

A taper is a section of material that

Increases in diameter at uniform rate

Major diameter

Largest diameter of thread

An accurate setover can be made by using the dial on the compound rest or cross slide or a dial indicator

Micrometer

The face of the thread dial rotates when the half nuts are

Not engaged

What are two major disadvantages of the offset tailstock method for cutting tapers

Only uses external Cut between centers

-profile inserts are most commonly used to cut threads because they can cut a range of thread pitches

Partial

On a single thread, the lead and are the same

Pitch

The must be known to measure thread accuracy with a thread micrometer

Pitch diameter

Of what is is a thread cutting stop

Provides a place to stop the threading tool but at the end of its cut and permits a nut to run up to the end of a thread

Always check the thread pitch after the first light cut with a

Rule and scrrw pitch gage

The offset tailstock method for turning tapers is also known as the tailstock method

Setover

A bar is a very accurately machined bar that is used in conjunction with gage blocks and sine tables to precisely measure angles

Sine

Minor diameter

Smallest diameter of a thread

Threads are usually employed to transmit motion

Square/acme

The most accurate method for cutting tapers is the

Taper attachment

A taper can be turned with the compound rest if the

Taper is converted to degrees

How are tapers specified

Taper per foot Taper per inch Angle Ratio

What are the two basic techniques used for testing the accuracy of a taper

Taper test gage Physically measuring

When cutting internal threads, tool infeed and removal from the cut are when cuttinf external threads

The reverse of those used

A thread dial is fitted to most lathes, what is its funtion

To know when to engage 1/2 nuts, which allow the tool bit to follow the origin cut

Screw threads have many uses, including

Transmitting motion Making measurements Making adjustments

What is a taper

Uniform rate increases or decreases on a shaft

The most accurate way to offset the tailstock center is to

Use a dial indicator

In machining technology what is a fishtail and what purpose does it serve

Used for grinding and setting the toolbit in position

What is on advantage a compound rest offers when used to cut tapers

Will cut external and internal tapers

Tailstock offset can be determined visually by measuring the distance between the center points, or between the on the base of the tailstock

Witness lines