Quality Management --

Contact:
Mr.Bright Zhou
Ms.Irene Guan
Tel：
86-29-86528771
Fax：
86-29-86515056
QQ：
1446639 / 2466609128
Email：
sft@sftbearings.com
Msn：
brcbrgs@hotmail.com
Skype：
foraparts

Selection of Bearing Type

Bearing Material

Rings(cups & cones) & Rolling elements
SFT bearing rings(cups & cones), balls & rollers are made of GCr15 high carbon chromium bearing steel
This steel No. is equal to the AISI 52100(U.S.A.), DIN 100Cr6(Germany), JIS SUJ2(Japan) etc.

Chemical composition of GCr15 steel:

Steel No.	Chemical composition %
GCr 15	C	Si	Mn	P	S	Cr	Mo	Cu	Ni
GCr 15	0.95-1.05	0.15-0.35	0.25-0.45	≤0.027	≤0.02	1.40-1.65	-	≤0.25	≤0.30

Contrast of steel no. in different countries

Country	China	ISO	U.S.A.	Japan	Germany	France	Sweden
Standard	GB		AISI	JIS	DIN	NF
Steel No.	GCr15	683/XVLL1	52100	SUJ2	100Cr6	100C6	SKF3

Hardness
Hardness of bearing rings(cups & cones) & rolling elements is HRC60～HRC65.

Retainers
SFT standard bearing retainers are made from cold rolled carbon steel. However, in cases of heavy duty, corrosive environment,misalignment and high speed operation, brass, stainless steel, nylon or phenolic resins will be used upon request.

Seals & Shields
SFT shields also employ carbon steel as standard.
Buna Nitrile is the standard and mostly common used material for SFT seals. Also, in order to meet the requirements of high temperature operation and compatibility with grease, a variety of other sealing materials are also applied to the seals.

Lubrication
Standard grease and oil are applied to SFT bearing products
SFT can also use special pointed brand grease or oil upon request

Tolerance

SFT bearing tolerance standard accords with Chinese national standard GB/T307(equal to ISO492)
The following are the contrast tables of Chinese national standard with the foreign standards.

Contrast of tolerance class for radial bearings in different countries(except tapered roller bearing)

Country	Standard	Tolerance class
China	GB/T307	0 (G)	6 (E)	5 (D)	4 (C)	2 (B)
ISO	ISO492	0	6	5	4	2
Sweden	SKF	0	P6	P5	P4	P2
Germany	DIN 620/2	P0	P6	P5	P4	P2
U.S.A.	ANSI B3.14	ABEC1	ABEC3	ABEC5	ABEC7	ABEC9
Japan	JIS B1514	0	6	5	4	2

Contrast of tolerance class for tapered roller bearing(metric size) in different countries

Country	Standard	Tolerance class
China	GB/T307	0	P6x		P5	P4
ISO	ISO492	0	6x		5	4
Sweden	SKF	0	CLN		P5
U.S.A.	ANSI	K		N	C	B	A
Japan	JIS	0	6x	6	5	4

Contrast of tolerance class for tapered roller bearing(inch size) in different countries

Country	Standard	Tolerance class
China	SFT	4		3
ISO	ISO492	4		3	0	00
Sweden	SKF	0		CL3	CL0
U.S.A.	ANSI	4	2	3	0	00

The standard manufacturing tolerance of SFT bearing is Class 0. Other tolerance grade can be supplied upon request

Tolerance of Class 0 radial bearing

Inner ring

d		△dmp		Vdp			Vdmp	△Bs		△B1s		VBs	Kia
over	incl.	high	low	Dimension series			max	high	low	high	low	max	max
mm		µm		8, 9	0, 1	2, 3, 4	µm	µm		µm		µm	µm
mm		µm		max (µm)			µm	µm		µm		µm	µm
2.5	10	0	-8	10	8	6	6	0	-120	0	-250	15	10
10	18	0	-8	10	8	6	6	0	-120	0	-250	20	10
18	30	0	-10	13	10	8	8	0	-120	0	-250	20	13
30	50	0	-12	15	12	9	9	0	-120	0	-250	20	15
50	80	0	-15	19	19	11	11	0	-150	0	-380	25	20
80	120	0	-20	25	25	15	15	0	-200	0	-380	25	25
120	180	0	-25	31	31	19	19	0	-250	0	-500	30	30
180	250	0	-30	38	38	23	23	0	-300	0	-500	30	40
250	315	0	-35	44	44	26	26	0	-350	0	-500	35	50
315	400	0	-40	50	50	30	30	0	-400	0	-630	40	60
400	500	0	-45	56	56	34	34	0	-450	0	-630	50	65
500	630	0	-50	63	63	38	38	0	-500	0	-800	60	70
630	800	0	-75	-	-	-	-	0	-750	-	-	70	80
800	1000	0	-100	-	-	-	-	0	-1000	-	-	80	90
1000	1250	0	-125	-	-	-	-	0	-1250	-	-	100	100
1250	1600	0	-160	-	-	-	-	0	-1600	-	-	120	120
1600	2000	0	-200	-	-	-	-	0	-2000	-	-	140	140

Outer ring

D		△Dmp		VDp				VDmp	△Cs		△C1s		VCs	Kea
over	incl.	high	low	Dimension series			With oil seals	max	high	low	high	low	max	max
mm		µm		8, 9	0, 1	2, 3, 4	or shields	µm	µm		µm		µm	µm
mm		µm		max (µm)				µm	µm		µm		µm	µm
6	18	0	-8	10	8	6	10	6	same as inner ring △Bs, △B1s, VBs					15
18	30	0	-9	12	9	7	12	7						15
30	50	0	-11	14	11	8	16	8						20
50	80	0	-13	16	13	10	20	10						25
80	120	0	-15	19	19	11	26	11						35
120	150	0	-18	23	23	14	30	14						40
150	180	0	-25	31	31	19	38	19						45
180	250	0	-30	38	38	23	-	23						50
250	315	0	-35	44	44	26	-	26						60
315	400	0	-40	50	50	30	-	30						70
400	500	0	-45	56	56	34	-	34						80
500	630	0	-50	63	63	38	-	38						100
630	800	0	-75	94	94	55	-	55						120
800	1000	0	-100	125	125	75	-	75						140
1000	1250	0	-125	-	-	-	-	-						160
1250	1600	0	-160	-	-	-	-	-						190
1600	2000	0	-200	-	-	-	-	-						220
2000	2500	0	-250	-	-	-	-	-						250

Tolerance of Class 0 tapered roller bearing (metric size)

Cone and width

d		△dmp		Vdp	Vdmp	△Bs		Kia	△Ts		△T1s		△T2s
over	incl.	high	low	max	max	high	low	max	high	low	high	low	high	low
mm		µm		µm	µm	µm		µm	µm		µm		µm
10	18	0	-12	12	9	0	-120	15	+200	0	+100	0	+100	0
18	30	0	-12	12	9	0	-120	18	+200	0	+100	0	+100	0
30	50	0	-12	12	9	0	-120	20	+200	0	+100	0	+100	0
50	80	0	-15	15	11	0	-150	25	+200	0	+100	0	+100	0
80	120	0	-20	20	15	0	-200	30	+200	-200	+100	-100	+100	-100
120	180	0	-25	25	19	0	-250	35	+350	-250	+150	-150	+150	-150
180	250	0	-30	30	23	0	-300	50	+350	-250	+150	-150	+150	-150
250	315	0	-35	35	26	0	-350	60	+350	-250	+150	-150	+150	-150
315	400	0	-40	40	30	0	-400	70	+400	-400	+200	-200	+200	-200
400	500	0	-45	45	34	0	-450	70	+400	-400
500	630	0	-50	50	38	0	-500	85	+500	-500
630	800	0	-75	75	56	0	-750	100	+600	-600
800	1000	0	-100	100	75	0	-1000	120	+750	-750
1000	1250	0	-125			0	-1250	120	+1000	-1000
1250	1600	0	-160			0	-1600	120	+1500	-1500
1600	2000	0	-200			0	-2000	120	+1500	-1500

Cup

D		△Dmp		VDp	VDmp	△Cs		Kea
over	incl.	high	low	max	max	high	low	max
mm		µm		µm	µm	µm		µm
18	30	0	-12	12	9	same as △Bs		18
30	50	0	-14	14	11			20
50	80	0	-16	16	12			25
80	120	0	-18	18	14			35
120	150	0	-20	20	15			40
150	180	0	-25	25	19			45
180	250	0	-30	30	23			50
250	315	0	-35	35	26			60
315	400	0	-40	40	30			70
400	500	0	-45	45	34			80
500	630	0	-50	50	38			100
630	800	0	-75	75	55			120
800	1000	0	-100	100	75			120
1000	1250	0	-125	125	94			120
1250	1600	0	-160	160	120			120
1600	2000	0	-200					120
2000	2500	0	-250					120

Tolerance of Class 4 tapered roller bearing (inch size)

Cone

d		△ds
over	incl.	high	low
mm		µm
-	76.2	+13	0
76.2	101.6	+25	0
101.6	266.7	+25	0
266.7	304.8	+25	0
304.8	609.6	+51	0
609.6	914.4	+76	0
914.4	1219.2	+102	0
1219.2	-	+127	0

Cup

D		△Ds		Kia,Kea,Sia,Sea
over	incl	high	low	max
mm		µm		µm
-	266.7	+25	0	51
266.7	304.8	+25	0	51
304.8	609.6	+51	0	51
609.6	914.4	+76	0	76
914.4	1219.2	+102	0	76
1219.2	-	+127	0	76

Width

d		D		△Ts
over	incl	over	incl	high	low
mm		µm		µm
-	101.6	-	-	+203	0
101.6	266.7	-	-	+356	-254
266.7	304.8	-	-	+356	-254
304.8	609.6	-	508	+381	-381
304.8	609.6	508	-	+381	-381
609.6	-	-	-	+381	-381

Tolerance of Class 0 tapered bore of radial bearing (tapered bore = 1:12)

d		△dmp		Vdp	△d1mp-△dmp
over	incl	high	low	max	high	low
mm		µm		µm	µm
18	30	+21	0	13	+21	0
30	50	+25	0	15	+25	0
50	80	+30	0	19	+30	0
80	120	+35	0	25	+35	0
120	180	+40	0	31	+40	0
180	250	+46	0	38	+46	0
250	315	+52	0	44	+52	0
315	400	+57	0	50	+57	0
400	500	+63	0	56	+63	0
500	630	+70	0	-	+70	0
630	800	+80	0	-	+80	0
800	1000	+90	0	-	+90	0
1000	1250	+105	0	-	+105	0
1250	1600	+125	0	-	+125	0
1600	2000	+150	0	-	+150	0

Tolerance of Class 0 tapered bore of radial bearing (tapered bore = 1:30)

d		△dmp		Vdp	△d1mp-△dmp
over	incl	high	low	max	high	low
mm		μm		μm	μm
80	120	+20	0	25	+40	0
120	180	+25	0	31	+50	0
180	250	+30	0	38	+55	0
250	315	+35	0	44	+60	0
315	400	+40	0	50	+65	0
400	500	+45	0	56	+75	0
500	630	+50	0	63	+85	0
630	800	+75	0	－	+100	0
800	1000	+100	0	－	+100	0
1000	1250	+125	0	－	+115	0
1250	1600	+160	0	－	+125	0
1600	2000	+200	0	－	+150	0

Clearance

SFT bearing radial clearance accords with the Chinese national standard GB/T 4604,
which is equal to ISO 5753

The clearances is classified into 5 groups, C2, C0, C3, C4, C5 with different applications
depending on customer's request

Radial clearance of deep groove ball bearing

d		C2		C0		C3		C4		C5
over	incl.	min.	max	min.	max	min.	max	min.	max	min.	max
mm		μm
2.5	6	1	8	5	15	10	20	15	25	21	33
6	10	2	9	6	17	12	25	19	33	27	42
10	14	2	10	6	19	13	26	21	35	30	48
14	18	3	12	8	21	15	28	23	37	32	50
18	24	4	14	10	23	17	30	25	39	34	52
24	30	5	16	11	24	19	35	29	46	40	58
30	40	6	18	13	29	23	40	34	53	46	66
40	50	6	19	14	31	25	44	37	57	50	71
50	65	7	21	16	36	30	50	45	69	62	88
65	80	8	24	18	40	35	60	54	83	76	108
80	100	9	27	22	48	42	70	64	96	89	124
100	120	10	31	25	56	50	83	75	114	105	145
120	140	10	38	30	68	60	100	90	135	125	175
140	160	15	44	35	80	70	120	110	161	150	210

Radial clearance of cylindrical bore self-aligning ball bearing

d		C2		C0		C3		C4		C5
over	incl	min	max	min	max	min	max	min	max	min	max
mm		μm
18	24	7	17	13	26	20	33	28	42	37	55
24	30	9	20	15	28	23	39	33	50	44	62
30	40	12	24	19	35	29	46	40	59	52	72
40	50	14	27	22	39	33	52	45	65	58	79
50	65	18	32	27	47	41	61	56	80	73	99
65	80	23	39	35	57	50	75	69	98	91	123
80	100	29	47	42	68	62	90	84	116	109	144
100	120	35	56	50	81	75	108	100	139	130	170
120	140	40	68	60	98	90	130	120	165	155	205
140	160	45	74	65	110	100	150	140	191	180	240

Radial clearance of tapered bore self-aligning ball bearing

d		C2		C0		C3		C4		C5
over	incl	min	max	min	max	min	max	min	max	min	max
mm		μm
-	10	0	25	20	45	35	60	50	75	-	-
10	24	0	25	20	45	35	60	50	75	65	90
24	30	0	25	20	45	35	60	50	75	70	95
30	40	5	30	25	50	45	70	60	85	80	105
40	50	5	35	30	60	50	80	70	100	95	125
50	65	10	40	40	70	60	90	80	110	110	140
65	80	10	45	40	75	65	100	90	125	130	165
80	100	15	50	50	85	75	110	105	140	155	190
100	120	15	55	50	90	85	125	125	165	180	220
120	140	15	60	60	105	100	145	145	190	200	245
140	160	20	70	70	120	115	165	165	215	225	275
160	180	25	75	75	125	120	170	170	220	250	300
180	200	35	90	90	145	140	195	195	250	275	330
200	225	45	105	105	165	160	220	220	280	305	365
225	250	45	110	110	175	170	235	235	300	330	395
250	280	55	125	125	195	190	260	260	330	370	440
280	315	55	130	130	205	200	275	275	350	410	485
315	355	65	145	145	225	225	305	305	385	455	535
355	400	100	190	190	280	280	370	370	460	510	600
400	450	110	210	210	310	310	410	410	510	565	665
450	500	110	220	220	330	330	440	440	550	625	735

Radial clearance of tapered bore spherical roller bearing

d		C2		C0		C3		C4		C5
over	incl	min	max	min	max	min	max	min	max	min	max
mm		μm
14	18	10	20	20	35	35	45	45	60	60	75
18	24	10	20	20	35	35	45	45	60	60	75
24	30	15	25	25	40	40	55	55	75	75	95
30	40	15	30	30	45	45	60	60	80	80	100
40	50	20	35	35	55	55	75	75	100	100	125
50	65	20	40	40	65	65	90	90	120	120	150
65	80	30	50	50	80	80	110	110	145