Thrust Ball Bearing

A thrust ball bearing is a type of bearing designed to support axial loads: the force that acts along the shaft, not across it. Small metal balls run between two washers. Each washer is grooved to form a raceway, so the parts rotate freely while the bearing takes the push, reducing friction between the moving parts. We supply thrust ball bearings such as the 51108 to order, in the 51100 and 51200 sizes below. Each type of thrust bearing, with balls or with rollers, is compared in our thrust bearing types guide.

Thrust ball bearing size chart: 51100 series

The thrust bearing size chart below gives the bore (d), the outside diameter (D) and the height of the assembled bearing (T), all in mm. Values are from the FULI catalog and match the ISO 104 metric sizes in the SKF tables [1]. For one size in full detail, see 51108 bearing dimensions.

Bearing	d (mm)	D (mm)	T (mm)
51100	10	24	9
51101	12	26	9
51102	15	28	9
51103	17	30	9
51104	20	35	10
51105	25	42	11
51106	30	47	11
51108	40	60	13
51109	45	65	14
51110	50	70	14
51111	55	78	16
51112	60	85	17
51113	65	90	18
51114	70	95	18
51115	75	100	19
51116	80	105	19
51117	85	110	19
51118	90	120	22

51200 series sizes

For the same bore, a 51200 bearing is wider and taller than a 51100. It has bigger bearing balls and carries more axial load.

Bearing	d (mm)	D (mm)	T (mm)
51200	10	26	11
51201	12	28	11
51202	15	32	12
51203	17	35	12
51204	20	40	14
51205	25	47	15
51206	30	52	16
51207	35	62	18
51208	40	68	19
51209	45	73	20
51210	50	78	22
51211	55	90	25
51212	60	95	26
51213	65	100	27
51214	70	105	27
51215	75	110	27
51216	80	115	28
51217	85	125	31
51218	90	135	35

The last two digits are the bore code. From 04 up, multiply by 5 to get the bore in mm, so 51208 has a 40 mm bore. Weights and load ratings are not listed here. Ask for them with the quote.

Single direction vs double direction

A single direction bearing has three parts: a shaft washer, a housing washer, and a ball and cage assembly between them [1]. It takes axial thrust one way only. When you compare samples, weigh the ball and cage assembly too, because a light brass cage can be hollow inside.

A double direction bearing has five parts. A central washer sits in the middle, with a ball set and a housing washer on each side [1] [2]. It holds the axial position both ways, so use it where the axial forces can reverse. Its bore code does not follow the single direction rule: a 52208 has a 30 mm bore, not 40 mm [1]. For a double direction bearing, send the full number and we will confirm the size.

Ball thrust or roller thrust

A ball thrust bearing uses steel balls as the rolling elements. Point contact keeps friction low and lets it run faster. Roller thrust bearings carry thrust loads on rollers, which give line contact and more capacity in the same space:

• Cylindrical roller types take high axial load and shock at low speed.
• Thrust needle types use needle rollers and fit where axial space is very short.
• Spherical roller types also take some load across the shaft and tolerate misalignment [1].

A tapered roller bearing is not a thrust bearing, but its taper lets it carry combined loads. Where most of the load acts across the shaft, a deep groove ball bearing is the usual choice. These roller types are not listed on our product pages. Send the number and we will tell you whether we can supply it.

How to choose a thrust ball bearing

Three points to consider when choosing one.

Load direction. A thrust ball bearing must not take radial load [1]. If there is radial loading as well, fit a second bearing for it. Common uses are vertical spindles, turntables and screw jacks, where the main force runs along the axis.

Speed. Thrust bearings cannot run as fast as radial bearings of the same size [1]. They also need a minimum axial load, or the balls skid instead of rolling [1]. They suit low-speed applications and moderate rotational speeds.

Which washer goes on the shaft. The shaft washer has the smaller, ground bore. Fit it against a shoulder. The housing washer has a larger bore and sits in the housing [1]. If they are swapped, the loose washer rubs and wears fast.

A 51108 order for a light-duty robot arm

In 2008 a customer in the United States bought 51108 thrust ball bearings from us. They went into a robot arm with a very light load that turned a few times a day. For that duty the material changed from GCr15 chrome bearing steel to 45 steel, close to C45 or AISI 1045, and rough grinding went from six passes to three. The price came down by about 30%, and there were no returns. The full story is in the 51108 bearing dimensions article.

What to send for a quote

1. The bearing number, with any prefix and suffix, or the d, D and T you measured.
2. Single or double direction.
3. The quantity per size.
4. The axial load and the speed in r/min, even rough figures.
5. The destination port.

Send it to sales@fuli-bearings.com or use the request a quote form. Other bearing types are on the products page.

Backed by 20+ years of bearing export experience in Linqing, Shandong.

Bearings produced under an ISO 9001:2015 quality management system. Certificate number and scope available on request.

Sources

1. https://www.skf.com/binaries/pub12/Images/0901d196802809de-Rolling-bearings---17000_1-EN_tcm_12-121486.pdf
2. https://www.nsk.com/tools-resources/abc-bearings/thrust-bearings/