7.6

Question 1

What is the difference between the high limits and the low limits called?

Answer 1

Tolerance

Question 2

What is the difference between the high limit of the inside component and the low limit of the surrounding component?

Answer 2

Allowance (the smallest clearance when fitting 2 components)

Question 3

What are the 2 clearance fits?

Answer 3

Free running (no force at all)
Running (light press)

Question 4

What are the 2 transition fits?

Answer 4

Light press (light push)
Push (light tap with hammer)

Question 5

What are the 3 interference fits?

Answer 5

Drive
Press
Force (considerable force)

Question 6

What is an extreme type of interference fit?

Answer 6

Shrink fit.

Heating outer component so it expands.

Question 7

What standard is the ISO fits for bearings and shafts?

Answer 7

BS4500

Question 8

What type of letter is the outer component?

Answer 8

Capital letter

Question 9

What type of letter is the inside component?

Answer 9

Lower case letter

Question 10

What do the letters on an ISO fit system indicate?

Answer 10

The tolerance position.

Question 11

What letter indicates zero fundamental deviation.

Answer 11

H or h

Question 12

What do letters beyond H specify?

Answer 12

Always give undersized holes and oversize shafts.

Question 13

What does a letter before H give?

Answer 13

Oversize hole and undersized shafts. Looser fit.

Question 14

What does the number that follows the deviation letter specify?

Answer 14

The tolerance for individual parts. (Scale of 1-16)

Question 15

What does DTI stand for?

Answer 15

Dial Test Indicator

Question 16

What do DTI’s measure?

Answer 16

Determine the amount of movement between certain engine and airframe parts.

Can also measure an out-of-round condition of a shaft on a plane rotation disk.