Download presentation

1
**Lecture 2 – Clearance Fits**

EML 2023 – Clearance Fits Lecture 2 – Clearance Fits

2
Cylindrical Fits

3
**Cylindrical Fits – English Units**

4
**Cylindrical Fits – English Units**

5
**Cylindrical Fits – English Units**

6
**Cylindrical Fits – English Units**

7
**Cylindrical Fits – English Units**

tolerance - difference between the limits of size for a single feature ; shaft ; hole .0040 limits of tolerance – the max and min sizes of a single feature allowance – the tightest fit between two mating parts ; .0050 nominal size – the general size of a shaft or hole ; 1.5 basic size – the size to which the plus-and minus is applied actual size – the measured size of the finished part fit - the degree of tightness or looseness between two assembled parts

8
**Cylindrical Fits – English Units**

clearance fit – gives a clearance between two assembled mated parts ; min clearance .005 ; max clearance .0115 transition fit interference fit line fit

9
**Cylindrical Fits – English Units**

clearance fit interference fit – a binding fit that requires the parts to be forced together, much as if they were welded transition fit – may range from a interference fit to a clearance fit between the mated parts line fit – results in surface contact or clearance when limits are reached

10
**Cylindrical Fits – English Units**

The ANSI B4.1 standard defines a series of fits between cylindrical features in inches for the basic hole system. The types of fits covered in the standard are: RC: running or sliding clearance fits LC: clearance locational fits LT: transition locational fits LN: interference locational fits FN: force and shrink fits

11
**Cylindrical Fits – English Units**

RC: running or sliding clearance fits RC1 to RC9 LC: clearance locational fits LC1 to LC11 LT: transition locational fits LT1 to LT6 LN: interference locational fits LN1 to LN3 FN: force and shrink fits FN1 to FN5

12
**Example – RC9 Fit hole and shaft have a basic diameter of 2.5”**

From Tables in Appendix 29 thousands of an inch

13
**Example – LT3 Fit hole and shaft have a basic diameter of 2.5”**

From Tables in Appendix 31 2.5012 2.5000 2.5008 2.5001 thousands of an inch

14
**Example – LN2 Fit hole and shaft have a basic diameter of 2.5”**

From Tables in Appendix 32 2.5012 2.5000 2.5021 2.5014 thousands of an inch

15
Example Problem

16
**Cylindrical Fits – Metric Units**

ANSI B4.2 standard basic size – the diameter from which limits are calculated upper and lower deviation – the difference between the hole or shaft size and the basic size tolerance - the difference between the maximum and minimum sizes

17
**Cylindrical Fits – Metric Units**

18
**Cylindrical Fits – Metric Units**

fundamental deviation – a letter grade that describes the deviation closest to the basic size International Tolerance (IT) grade – a series of tolerances that vary with the basic size to provide a uniform level of accuracy within a given grade there are 18 IT grades: IT01, IT0, IT1, …, IT16

19
**Cylindrical Fits – Metric Units**

Hole basis a system of fits based on the minimum hole size as the basic diameter the fundamental deviation for a hole-basis system is “H” Appendices 35 and 36 give hole-basis data for tolerances Shaft basis a system of fits based on the maximum shaft size as the basic diameter the fundamental deviation for a hole-basis system is “h” Appendices 37 and 38 give shaft-basis data for tolerances

21
**Cylindrical Fits – Metric Units**

22
**Cylindrical Fits – Metric Units**

23
**Example 1 determine the shaft and hole limits for: hole-basis system**

a close running fit a basic diameter of 49 mm use a preferred size

25
Example 1 use a preferred basic diameter of 50 mm use a fit of H8/f7

26
**Example 2 determine the shaft and hole limits for: hole-basis system**

a location transition fit a basic diameter of 57 mm use a preferred size

28
Example 2 use a preferred basic diameter of 60 mm use a fit of H7/k6

29
**Example 3 determine the shaft and hole limits for: hole-basis system**

a medium drive fit a basic diameter of 96 mm use a preferred size

31
Example 3 use a preferred basic diameter of 100 mm use a fit of H7/s6

32
**Nonstandard Fits, Nonpreferred Sizes**

determine the shaft and hole limits for: hole-basis system a close running fit a basic diameter of 45 mm (do not change to a preferred size)

34
**Nonstandard Fits, Nonpreferred Sizes**

use a fit of H8/f7

Similar presentations

Presentation is loading. Please wait....

OK

Tolerance Calculations

Tolerance Calculations

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on chapter 3 atoms and molecules activity Ppt on shell scripting interview Ppt on latest technology in civil engineering Ppt on developing leadership skills Ppt on non ferrous metals and alloys Ppt on haunted places in india Ppt on low level language of computer Ppt on switching devices on netflix Ppt on history of pie in math Medical templates free download ppt on pollution