M7c3

39問 • 2ヶ月前

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In files the grade indicates the

degree of coarseness of the teeth.

Single cut files are used for cutting hard metals, they have an unbroken series of cuts, parallel with each other but running at

an angle of 60-80° to the length of the file.

Flat Chisel

•65° is for tool steel. •50° is for mild steel . •30° is for aluminum

Cross-cut chisel The cutting edge varies in width

from 1⁄8” to 3⁄8”

The chisel is reduced in width behind the cutting edge to

give clearance when cutting grooves.

The chisel is forged down to width to give strength to the cutting edge.

The point angle varies from 65° for steel to 30° for aluminum.

the Consideration for selecting correct chisel for the job must be given to both

the nature of the work and to the material that is to be cut

The choice of blade for a hacksaw is for

soft metal require coarse blades and hard metal require fine blade.

The choice of teeth per inch (TPI) of a hacksaw is governed

by the shape and thickness of the material to be cut.

……..must be in contact with the material at any given time.

At least three teeth

……….are similar in general shape but the frames are deeper and sometimes adjustable for length. Serrated and hardened clamps ensure a firm grip on the blades, which are 5" long with TPI from 32 to 80.

Piercing saws

Used for fine sawing if intricate shapes in thin sheet

A flange spanner is a ring spanner with

very thin walls and a small crank

C’ spanner and adjustable ‘C’ spanner This form of spanner is for use on ………….or a range of adjustable sizes

slotted circular nuts and collars and is available in set sizes

One of scraper in general use is flat type is used

for producing accurate flat surface

Tri-wing some airlines use screws with a special screw head produced by Phillips screw company………………instead of the four slots found on the regular cross point screw

These screws have three slots

The selection of a punch or drift depend on:

item to be fitted or removed, its location and material.

What is difference between Gauging and measuring instruments ?

Gauging differs from measuring in that measuring instruments are used to give a direct numerical value to a dimension whilst gauges are used to compare a dimension to a known

Ring gauges check for

dimension, roundness and taper

If ring gauges used in Go no Go situation

two ring gauge must be used

Micrometers used to take accurate imperia or metric measurement. Used when additional accuracy is required It………..by the addition of Vernier scale on the barrel.

reads 0.0001” or 0.002mm

Always check

the zero reading of the micrometer before used.

The standard drill is machined from cylinder bar. It is ground to a point at one end with an

Angle of 118° normally also although it’s may be between 90° for very soft materials and 150° for hardened materials

Countersink drills

They are made with an included angle of between 60° and 120° depending on the head angle of the fastener to be installed.

A power nibbler is a tool used for rough cutting small-to-medium sized holes in skins.

It is hand held and has a reciprocating cutter

When cutting an internal and a mating external thread the

internal thread should be cut first.

The flat surface is used for most general-purpose work whilst the ball pein is used primarily for riveting-type operations

Ball Pein

Used for finishing beaten work.

Planishing hammer

Used for shaping internal curves in sheet metal.

Bossing mallet

Starting punches

are typically used to aid in driving bolts and pins from their holes

A Vernier Callipe used to

measure inside and outside dimensions and depth.

a Vernier calliper ensure accurate readings :

0.02 mm accuracy

The main scale of a metric vernier caliper is:

calibrated in millimeter and half millimeter.

The sine bar is used to

produce angles using slip gauges.

Imperial unit uses:

fractions of an inch .

Selection and use of pliers and cutters based on:

1- the task to be performed 2- position and access requirement.

Drill gauges used for

checking the diameter drills, reamers, and rods.

The head of combination set is used to find the centres of circular bars is called:-

Center head.

The main head of combination set has one edge at 90° and the other at 45° to the rule. this head is called :-

Square head.

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