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Marking Out

Good Morning

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Todays aims

Ensure that you understand and canuse basic tooling

Learn about the main types of datum

Practice planning a task.

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Tooling

Scribe Very sharp point

Sharpened with an oil

stone.

Used for very sharp

lines Should not be ground

sharp

Cuts into the work to

produce its mark.

Soft materials only

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Centre punch & Dot punch

Centre punch:

Used for pre-drillingpunches, and chisiling

Dot punch:

Used for lighter punching.

Provides a protection line

Prevents slip of callipers

and compasses.

Point angle 90

Centre punch

Point angle 60

Dot punch

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Dividers Odd leg callipers

Used to scribe a circle or

a radius. Tips need to be needle

sharp and level.

Used to scribe following

a datum edge or offsetany other edge.

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Questions

What do we use a height gauge for?

What must we do before we use a

height gauge?

What do we use to keep our workPerpendicular when marking out?

What should we mark out from:

A) The table

B) Surface plate

C) Surface plate and parallel strip.

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Datum types

What is the purpose of a datum?

There are 3 main types of datum that you

will need to know:

Point datum: A single point from which

all measurements are marked out.

Can you think when this would be

used?

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Point Datum All taken from one

point

A

B

D

C

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Line Datum

This is a single line or sometimes twolines that all measurements are taken

from.

The lines normally run along the

central axis of a symmetrical shape.

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The line datum's in green are where all

measurements are taken from

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Surface datum

The most common type of datum

Taken from two edges perpendicular

to each other

Enables easy marking out using

co-ordinates for centres and simplemeasurements for length.

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Surface datum

A

B

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Marking out planning

Before you mark out your componentyou must first plan what you are goingto do and in what order.

This plan includes equipment neededand methods used.

It enables the item to be markedefficiently without missing andmeasurements out

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Your task

For the item you marked out last weekyou are to produce a plan.

It must be logical and methodical.

All measurements are to be included

and how these will be produced.

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Op Dist from A

(MM)

Dist from B

(MM)

Method of

marking

Equipment Feature

produced

5 0 10 scribe Height gauge,

surface plate,

angle plate

10mm step

10 10 10 scribe same 15mm vertical

line (left hand)

15

20

25

30

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Well done

That is another good lesson.

Next week we will be practicing:

Planning

Marking out

Using tools