A8-25N21

A8-25N21 DRAWING AND SPECIFICATION

JCB BEARING four point contact ball internal gear 0in-39.3700in

A8-25N21 SPECIFICATION

Slewing Bearing: A8-25N21

Inner diameter (d): 21.350 in

Outer diameter (D): 28.750 in

Overall height (T): 3.500 in

Outer ring height (H1): 2.880 in

Inner ring height (H2): 3.380 in

Weight: 228 Ibs

External bolt circle dia (J1): 27.375 in

Number of bolt holes per hole circle (n1):18

External bolt hole type : Selected by user

External bolt hole diameter (N1): 5/8-11 in

Internal bolt circle dia (J2): 23.625 in

Number of bolt holes per hole circle (n2):18

Internal bolt hole type : Selected by user

Internal bolt hole diameter (N2): 5/8-11 in

Tooth number (z):87

Module of gear (DP):4

Tooth width (B): 2.00 in

A8-25N21 DRAWING

A8-25N21 drawing is reference for user, if you request for A8-25N21 formal drawing , please contact with us: sales@jcb-bearing.com, the A8-25N21 official drawing will be submitted to user.

A8-25N21

DOWNLOAD PDF DRAWING

RAW MATERIAL

For slewing bearing ring , usually the raw material is alloy steel, such as 50Mn, C45E, 42CrMo (DIN 42CrMo4, AISI 4142), and some special non-ferrous metals, such as aluminum, stainless steel and so on, it should be selected according to user’s application if user have special request.
For slewing bearing cage, 1). steel 2). Nylon 66 or 1010 (Polyamide66) 3). Polyetheretherketone 4. Brass 5. Other cage materials.
For spacer, raw material should be Nylon 66 (Polyamide66) or Nylon 1010. it should be selected according to user’s application if user have special request.
For seal, raw material is oil resistant rubber I-3, or other special raw material for seal.
Rolling element (ball or roller), high chrome alloy bearing steel,GCr15 and GCr15SiMn, or stainless steel.

CORROSION PROTECTION

SPRAY COATING

Metal surface spray painting is a very important means of maintaining metal corrosion resistance.

BLACK COATING

Oxidize the surface of steel parts to form dense oxide film protective layer, improving the anti-rust ability of steel parts.

ZINE PLATING

Surface treatment technology that coats the surface of metal with a layer of zinc for rust prevention.

NICKEL PLATING

The electroplated nickel layer has high stability in the air, because metallic nickel has strong passivation ability

TECHNICAL INFORMATION

BOLT HOLES TYPE

Bolt holes type should be selected according to their application with order if user have special request.

BOLTS

Preload forces and tightening torques
Preload Forces and Tighiening Torques for Metric Bolts (Friction Coefficientp=0.14)
Strength Class of the Bolt according to DIN/ISO 898			8.8		10.9		12.9
Yield Strength Roz [MPa]			640 for≤M 16 660 for>M 16		940		1100
Bolt Size according to DIN 13	Pre-loaded Cross-Section A₈ [mm²]	Thread Cross-SectionAd。 [mm²]	Preload ForceFu [N]	Tightening Torque Mu [Nm]	Preload ForceFu [N]	Tightening TorqueMu [Nm]	Preload ForceFu [N]	Tightening Torque Mu [Nm]
M5	14.2	12.7	6,400	5.5	9,300	8.0	10,900	9.3
M6	20.1	17.9	9,000	9.3	13,200	13.9	15,400	16.2
M8	36.6	32.8	16,500	22.5	24,200	33	28,500	38
M10	58	52.3	26,000	45	38,500	67	45,000	78
M12	84.3	76.2	38,500	78	56,000	117	66,000	135
M14	115	105	53,000	126	77,000	184	90,000	216
M16	157	144	72,000	193	106,000	279	124,000	333
M18	193	175	91,000	270	129.000	387	151,000	459
M20	245	225	117,000	387	166,000	558	194,000	648
M22	303	282	146,000	522	208,000	747	243,000	873
M24	353	324	168,000	666	239,000	954	280,000	1,116
M27	459	427	221,000	990	315,000	1,395	370,000	1,665
M30	561	519	270,000	1,350	385,000	1,890	450,000	2,250
M33	694	647	335,000	see note	480,000	see note	560,000	see note
M36	817	759	395,000		560,000		660,000
M39	976	913	475,000		670,000		790,000
M42	1,120	1,045	542,000		772,000		904,000
M45	1,300	1,224	635,000		905,000		1,059,000
M48	1,470	1,377	714,000		1,018,000		1,191,000
M52	1,760	1,652	857,000		1,221,000		1,429,000
M56	2,030	1,905	989,000		1,408,000		1,648,000
M60	2,360	2,227	1,156,000		1,647,000		1,927,000

LUBRICATIONA

LUBRICATION SPOTS TYPE

lubrication spots type should be selected according to user’s application with order.

RECOMMENDED LUBRICANTS

Lubricant type

Producer

Raceway

Gear

Aralub HLP 2

(-30 °C to +120 °C)

Aralub MKA – Z 1

(-20 °C to +200 °C)

Energrease LS – EP 2

(-25 °C to +140 °C)

Energrease LC 2

(-30 °C to +150 °C)

Spheerol EPL 2

(-20 °C to +140 °C)

Castrol LZV – EP

(-30 °C to 150 °C)

Epexa 2

(-20 °C to +140 °C)

Cardrexa DC 1

(-20 °C to +120 °C)

Beacon EP 2

(-20° C to +110 °C)

Multi purpose grease (Moly)

(-25 °C to +150 °C)

Ronex MP

(-25 °C to +130 °C)

Dynagear

(-20° C to +100 °C)

agermeister EP 2

(-20 °C to +130 °C)

Ceplattyn 300

(-30 °C to +250 °C)

Klüberlub BE 41-542

(-20 °C to +140 °C)

Grafloscon C-SG 0 Ultra

(-30 °C to +200 °C)

Mobilux EP 2

(-25 °C to +120 °C)

Mobilgear OGL 461

(-20 °C to +120 °C)

Shell Alvania EP 2

(-25 °C to +130 °C)

Shell Malleus OGH

(-20 °C to +130 °C)

Multifak EP 2

(-30 °C to +120 °C)

Crater 2x Fluid or 5x Fluid

(-12 °C to +116 °C)

AXIAL CLEARANCE

Axial clearance should be selected according to their application with order if user have special request. Dpw: outer diameter (mm)

		BEARING GRADE
		P0		P6		P5
Dpw mm		AXIAL CLEARANCE (μm)
OVER	TO	OVER	TO	OVER	TO	OVER	TO
280	450	70	170	50	130	30	90
450	710	100	220	70	170	40	120
710	1120	120	280	100	220	50	150
1120	1800	150	350	100	260	60	180
1800	2800	200	440	150	350	80	240
2800	4500	260	540	200	440	100	300

RUNNING ACCURACY

RUNNING ACCURACY should be selected according to their application with order if user have special request.

Outer diameter mm
﹥			150	400	630	1000	1600	2500	4000	6300	9000
≤			400	630	1000	1600	2500	4000	6300	9000	12500
RUNNING ACCURACY PARAMETER	BEARING GRADE	RUNNING ACCURACY VALUE (MAX μm)
Sin Sen	P0	–	85	110	140	170	220	280	350	500	－
Sin Sen	P6	–	43	55	70	85	110	140	180	240	－
Sin Sen	P5	–	30	38	50	65	77	100	130	170	－
Kin Ken	P0	–	120	150	200	250	310	390	500	650	－
Kin Ken	P6	–	63	77	100	120	150	190	250	330	－
Kin Ken	P5	–	43	55	70	85	110	140	170	230	－
Frin Fren	P0	–	280	340	420	480	630	750	850	1000	－
Frin Fren	P6	–	220	250	280	360	420	560	630	760	－
Frin Fren	P5	–	160	180	220	250	320	420	480	580	－

DIMENSION TOLERANCES

		△Ts	△dsb			△Dsb
dimension		grade of tolerance
﹥	≤	P0、P6、P5	P0	P6	P5	P0	P6	P5
150	400	±0.6	H9	H8	H7	h9	h8	h7
400	630	±0.8
630	1000	±1.0
1000	1600	±1.2
1600	2000	±1.4
2000	2500	±1.6	H10	H9	H8	h10	h9	h8
2500	4000	±1.8
4000	6300	±2.0
6300	9000	±2.2
9000	12500	±2.5

OTHER TECHNICAL INFORMATION

BALL GRADE

	Steel ball grade
	Dw	over	＞0	＞30	＞50
Bearing grade	Dw	to	＜30	＜50	＞50
P0、P6	DW: ball diameter		G40	G60	G100
P5	DW: ball diameter		G20	G40	G60

DEPTH OF HARDENED LAYER OF RACEWAY

DEPTH OF HARDENED LAYER OF RACEWAY (mm)
Dw	≤30	﹥30～40	﹥40～50	﹥50
DS	≥3.0	≥3.5	≥4.0	≥5.0
Remark: DS: depth of hardened layer of bearing raceway as over HRC48 hardness mm

MANUFACTURE & INSPECTION

FORGING BLANK PROCESS

QUALITY MATERIAL 42CrMo
Quality material 42CrMo which we source from famous steel mill – Special Steel Group of CITIC Pacific (CITIC Special Steel Group)
RAW MATERIAL HEATING BEFORE FORGING PROCESS

Heating of raw materials is an important step in the forging process and is also the core technology for final product quality assurance.
PROCESS OF RING ROLLING MACHINE
The ring is finally formed using a ring rolling machine, with the size range ranging from 1000 mm to 6500 mm.

MECHANNICAL PROCESS

CNC MACHINING CENTER
The CNC machining centers can greatly improve production efficiency
CNC GRIDING MACHINE
CNC grinding machines can effectively ensure the machining accuracy of bearing parts, thereby meeting various technical requirements for precision bearings.
HIGH SPEED GEAR MILLING MACHINE
The production efficiency of high-speed gear hobbing machines is 2-3 times higher than that of conventional gear hobbing machines. The precision of processed gears can reach level 8, and the maximum processing range is 3500mm.

INSPECTION

3D COORDONATE MEASURING MACHINE
The inspection of precision slewing bearings is carried out using three-coordinate inspection equipment
DIMENSION INSPECTION
Complete testing instruments and scientific testing methods ensure product quality.
UNDT INSPECTION
All slewing bearing parts are subjected to 100% non-destructive testing (NUDT) during processing and before assembly.

PACKING AND STORAGE

PACKING

The bearing surface is coated with anti-rust oil, covered with plastic film, and wrapped with high-strength nylon tape.

Bearings and bearing accessories are placed in the packaging box, including product certificates and instructions for use. Various markings on the outside of the packaging box are clear.

The bearings are firmly fixed in the packaging box, and waterproof and moisture-proof measures are taken to ensure that the bearings are not damaged during transportation.

STORAGE

Bearings must pass the inspection by the quality inspection department and be accompanied by a certificate before they leave the factory.

Bearings should be placed horizontally on a dry, ventilated, flat site, and should be isolated from chemicals and other corrosive items during storage

If bearings need to be stacked on top of each other, more than three wooden pads of equal height should be placed evenly between each set of bearings along the circumferential direction, upper and lower pads should be placed same position.

TRANSPORTATION

User can arrange transportation
according to this Packing List

We have three transportation way for customer to reference.
1.Delivery by express
2.Delivery by sea
3.Delivery by air

During transportation, the bearings should be placed horizontally on the vehicle, and measures should be taken toprevent sliding and vibration.Auxiliary supports can be added if necessary.

We accept to deliver bearing by customer’s account of Express or using our account of Express.

MAINTENANCE

Bearings should be replenished with grease regularly. When replenishing grease, rotate the bearing at the same time to distribute the grease evenly until the new grease squeezes out of the oil hole or sealing lip.

Under normal circumstances, bearings in use should be filled with new grease every six months. Under harsh environmental conditions, the fat replenishment cycle can be shortened appropriately

If the bearing is out of service for more than half a year, add new grease before use

WARRANTY POLICY

JCB bearing provides a broad range of maintenance and technical support that helps user best solve their usage and installation problems.
All JCB bearing products are shipped with 4 years standard warranty. Optional advanced services and warranties are available and vary by product family and region. You can contact JCB bearing sales representatives for more information.
This Warranty Policy shall be globally applicable and enforced in all countries. In the event that any terms of this Warranty Policy conflicts with local laws, local laws shall prevail.

WARRANTY TERMS

JCB轴承

PRODUCT CERTIFICATEION

CLASSIFICATION SOCIETY

According to customer requirements, classification society inspection reports can be provided.

PROFESSIONAL INSPECTION AGENCY

According to customer requirements, test reports from third-party professional testing agencies can also be provided.

NATIONAL TESTING CENTER

According to customer requirements, test reports from China’s national testing institutions can also be provided.

SALE RANGE IN WORLDWIDE

EUROPE

Main applications include sewage treatment, port machinery, and ship lifting equipment.

NORTH AMERICA

Mainly used in large transportation vehicles, forest machinery, and medical equipment

ASIA

Mainly used in amusement facilities, machine tools, and construction equipment

A8-25N21

DRAWING AND SPECIFICATION

TECHNICAL INFORMATION

MANUFAC AND INSPECTION

PACKING AND STORAGE

A8-25N21 DRAWING AND SPECIFICATION

A8-25N21 SPECIFICATION

A8-25N21 DRAWING

RAW MATERIAL

CORROSION PROTECTION

SPRAY COATING

BLACK COATING

ZINE PLATING

NICKEL PLATING

TECHNICAL INFORMATION

BOLT HOLES TYPE

BOLT HOLES TYPE

BOLTS

LUBRICATIONA

LUBRICATION SPOTS TYPE

RECOMMENDED LUBRICANTS

AXIAL CLEARANCE

RUNNING ACCURACY

DIMENSION TOLERANCES

OTHER TECHNICAL INFORMATION

BALL GRADE

DEPTH OF HARDENED LAYER OF RACEWAY

MANUFACTURE & INSPECTION

FORGING BLANK PROCESS

MECHANNICAL PROCESS

INSPECTION

PACKING AND STORAGE

PACKING

STORAGE

TRANSPORTATION

MAINTENANCE

WARRANTY POLICY

WARRANTY TERMS

PRODUCT CERTIFICATEION

CLASSIFICATION SOCIETY

PROFESSIONAL INSPECTION AGENCY

NATIONAL TESTING CENTER

SALE RANGE IN WORLDWIDE

EUROPE

NORTH AMERICA

ASIA

Contact Information