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2-) Locational Fits [LC,LT,LN]:


Locational Clearance Fits are divided into three groups. these fits are intended to determine only the location of the mating parts. They may provide accurate or rigid location like interference fit or some freedom of location like clearance fit. These three fits are Locational Clearance Fits (LC), Locational Transition Fits (LT), Interference Fits (LN). Locational Fits are not for running machinery, it is for location of the mating parts. Some example: Parts of machines fixed to shafts using pins, bearing bushings, precise fits of machines and preparations, exchangeable wheels, bolts, retaining and distance rings, parts of machines fixed to shafts using pins, rivets or welds, etc


a-) Locational Clearance Fits [LC]: This kind of fits are for parts which are normally stationary but which can be freely assembled and disassembled. With Locational clearance fits, parts run from snug fits for parts requiring accuracy of location through the medium clearance to the looser fastener fits where freedom of assembly is necessary. The coupled parts must be fixed mechanically to prevent any moving part against the other during assembly. Some of the use for this fits are bearing bushings, exchangeable wheels, bolts, retaining and distance rings, rivets, parts of machines fixed to shafts using pins, or welds, etc. The lower the class like LC1, LC2 for the precise guiding and centering of parts, the higher the class like LC10, LC11 for the free fits with great clearances and maximum tolerances.The tolerance of mating parts and fit clearance increases with increasing class of the fit. Tighter than RC fits, but the shaft and hole may be the same size. LC fits allow the shaft to be located more accurately than the RC fits but may still be loose. SHAFT "d9" with Hole "H8" is generally suitable for loose running fits such as Plummer block bearing and loose pulleys. SHAFT "e8" with Hole "H8" is recommended for general loose clearance fits and for properly lubricated bearings requiring appreciable clearance. SHAFT "f7" with Hole "H7" and " f8" with Hole "H8" are recommended to provide a normal running fits. This fit is widely used a normal grease-lubricated or oil-lubricated bearing where no substantial temperature differences are encountered. Typical applications are gear box shaft bearings and small electrical motor and pump bearings. SHAFT "g5" with Hole "H6" and "g6" with Hole "H7" are expensive to manufacture since the clearances are small and they are not recommended for running fits except in precision equipment where shaft loadings are very light. Typical applications are the bearings for accurate link work and for piston and slide valves. in addition, they are often used for spigot or location fits. SHAFT "h7" with Hole "H8" has an upper limit of zero although in practice a slight clearance will usually be found. it is used for non-running parts and is useful for normal location and spigot fits and may be used as a precision fit.


Graphical Representation of ANSI B4.1-1967 Locational Clearance Fits Table




Locational Clearance Limits and Fits For Cylindrical Parts
[(ANSI B4.1-1967,R1987)][Table LC1-LC5]


All limits shown in chart below are in thousandths of an inches. Symbols H6,H7,s6, etc. are Shaft and Hole designations used in American-British-Canadian System (ABC). Limits for Shaft and Hole are applied algebraically to the Nominal (basic) size to obtain the limits of the size for the parts. All data given in bold in the chart below are in accordance with ABC agreements. The values given under the "Clearance Limits Column" represent min and max amounts of clearance resulting from application of standard tolerance limits.


VALUES SHOWN BELOW ARE IN THOUSANDTHS OF AN INCHES
Nominal (Basic) Size
Ranges (Inches)		 Class LC1Class LC2Class LC3 Class LC4Class LC5
Clearance
Limits		Standard Tolerance LimitsClearance
Limits		Standard Tolerance Limits Clearance
Limits		Standard Tolerance LimitsClearance
Limits		 Standard Tolerance LimitsClearance
Limits		Standard Tolerance Limits
OverToHole
H6		Shaft
h5		Hole
H7		Shaft
h6		 Hole
H8		Shaft
h7		Hole
H10		Shaft
h9		Hole
H7		Shaft
g6
00.120
0.45		+0.25
0		0
-0.2		0
0.65		+0.4
0		 0
-0.25		0
-0.25		0
1.0		+0.6
0		0
-0.4		0
2.6		 +1.6
0		0
-1.0		0.1
0.75		-0.1
-0.35
0.120.240
0.5		+0.3
0		0
-0.2		0
0.8		+0.5
0		 0
-0.3		0
1.2		+0.7
0		0
-0.5		0
3.0		+1.8
0		 0
-1.2		0.15
0.95		+0.5
0		-0.15
-0.45
0.240.400
0.65		+0.4
0		0
-0.25		0
1.0		+0.6
0		 0
-0.4		0
1.5		+0.9
0		0
-0.6		0
3.6		+2.2
0		 0
-1.4		0.2
1.2		+0.6
0		-0.2
-0.6
0.400.710
0.7		+0.4
0		0
-0.3		0
1.1		+0.7
0		 0
-0.4		0
1.7		+1.0
0		0
-0.7		0
4.4		+2.8
0		 0
-1.6		0.25
1.35		+0.7
0		-0.25
-0.65
0.711.190
0.9		+0.5
0		0
-0.4		0
1.3		+0.8
0		 0
-0.5		0
2.0		+1.2
0		0
-0.8		0
5.5		+3.5
0		 0
-2.0		0.3
1.6		+0.8
0		-0.3
-0.8
1.191.970
1.0		+0.6
0		0
-0.4		0
1.6		 1.0
0		0
-0.6		0
2.6		+1.6
0		0
-1.0		0
6.5		+4.0
0		0
-2.5		0.4
2.0		+1.0
0		 -0.4
-1.0
1.973.150
1.2		+0.7
0		0
-0.5		0
1.9		+1.2
0		 0
-0.7		0
3.0		+1.8
0		0
-1.2		0
7.5		+4.5
0		 0
-3.0		0.4
2.3		+1.2
0		-0.4
-1.1
3.154.730
1.5		+0.9
0		0
-0.6		0
2.3		+1.4
0		 0
-0.9		0
3.6		+2.2
0		0
-1.4		0
8.5		+5.0
0		 0
-3.5		0.5
2.8		+1.4
0		-0.5
-1.4
4.737.090
1.7		+1.0
0		0
-0.7		0
2.6		+1.6
0		 0
-1.0		04.1+2.5
0		0
-1.6		0
10.0		+6.0
0		 0
-4.0		0.6
3.2		+1.6
0		-0.6
-1.6
7.099.850
2.0		+1.2
0		0
-0.8		0
3.0		+1.8
0		 0
-1.2		0
4.6		+2.8
0		0
-1.8		0
11.0		+7.0
0		 0
-4.5		0.6
3.6		+1.8
0		-0.6
-1.8
9.8512.410
2.1		+1.2
0		0
-0.9		0
3.2		+2.0
0		 0
-1.2		0
5.0		+3.0
0		0
-2.0		0
13.0		+8.0
0		 0
-5.0		0.7
3.9		+2.0
0		-0.7
-1.9
12.4115.750
2.4		+1.4
0		0
-1.0		0
3.6		+2.2
0		 0
-1.4		0
5.7		+3.5
0		0
-2.2		0
15.0		+9.0
0		 0
-6.0		0.7
4.3		+2.2
0.0		-0.7
-2.1
15.7519.690
2.6		+1.6
0		0
-1.0		0
4.1		+2.5
0		 0
-1.6		0
6.5		+4.0
0		0
-2.5		0
16.0		+10.0
0		 0
-6.0		0.8
4.9		+2.5
0		-0.8
-2.4
19.6930.090
3.2		+2.0
0		0
-1.2		0
5.0		+3.0
0		0
+2.0		 0
8.0		+5.0
0		0
-3.0		0
20.0		+12.0
0		 0
-8.0		0.9
5.9		 +3.0
0		-0.9
-2.9
30.0941.490
4.1		+2.5
0		0
-1.6		0
6.5		+4.0
0		0
-2.5		 0
10.0		+6.0
0		0
-4.0		0
26.0		+16.0
0		 0
-10.0		1.0
7.5		+4.0
0		-1.0
-3.5
41.4956.190
5.0		+3.0
0		0
-2.0		0
8.0		+5.0
0		0
-3.0		 0
13.0		+8.0
0		0
-5.0		0
32.0		+20.0
0		0
-12.0		 1.2
9.2		+5.0
0		-1.2
-4.2
56.1976.390
6.5		+4.0
0		0
-2.5		0
10.0		+6.0
0		0
-4.0		 0
16.0		+10.0
0		0
-6.0		0
41.0		+25.0
0		0
-16.0		 1.2
11.2		6.0
0		-1.2
-5.2
76.39100.90
8.0		-5.0
0		0
-3.0		0
13.0		+8.0
0		0
-5.0		 0
20.0		+12.0
0		0
-8.0		0
50.0		+30.0
0		0
-20.0		 1.4
14.4		+8.0
0		-1.4
-6.4
100.9131.90
10.0		+6.0
0		0
-4.0		0
16.0		+10.0
0		0
-6.0		 0
26.0		+16.0
0		0
-10.0		0
65.0		+40.0
0		0
-25.0		 1.6
17.6		+10.0
0		-1.6
-7.6
131.9171.90
13.0		+8.0
0
-5.0		0
20.0		+12.0
0		0
-8.0		 0
32.0		+20.0
0		0
-12.0		0
80.0		+50.0
0		0
-30.0		 1.8
21.8		+12.0
0		-1.8
-9.8
171.92000
16.0		+10.0
0		0
-6.0		0
26.0		+16.0
0		0
-10.0		 0
41.0		+25.0
0		0
-16.0		0
100		+60.0
0		0
-40.0		 1.8
27.8		16.0
0		-1.8
-11.8

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