The terminology used by Hoover Precision Products, Inc. for balls conforms to the American National Standard sponsored by the Anti-Friction Bearing Manufacturers Association, Inc. (ANSI/AFBMA Std. 10-1983) (www.americanbearings.org/).

 

Grade: A specific combination of dimensional form and surface roughness tolerance. A ball grade is designated by a grade number.

Deviation from Spherical Form: Determined by rotation of the ball against a linear transducer with less than 4 grams age force. The resulting polar chart is interpreted using the minimum circumscribed circle method (MCC) per ABMA std. 10.

Lot Diameter Variation: The difference between the mean diameter of the largest ball and that of the smallest ball in the lot.

Ball Diameter Variation: The difference between the largest and the smallest actual single diameter of one ball.

Ball Gage: The prescribed small amount by which the lot mean diameter should differ form nominal diameter, this amount being one of an established series of amounts. A ball gage, in combination with the ball grade and nominal ball diameter should be considered as the most exact ball size specification to be used by a customer for ordering purposes.

Nominal Ball Diameter: The diameter value that is used for the purpose of general identification of a ball size, e.g. 1/4", 6mm, etc.

Nominal Ball Diameter Tolerance: The maximum allowable deviation of any ball by a specific indenting shape.

Specific Diameter: The mount by which the lot mean diameter differs from the nominal diameter, accurate to the container marking increment for that grade.  The specific diameter should be marked on the unit container.

Container Marking Increment: The standard unit steps in micrometers or in microinches, used to express the specific diameter.

Hardness: The measure of resistance to penetration of the ball surface or truncated flat of the ball by a specific indenting shape.

Surface Roughness: Surface roughness consist of all those irregularities which form surface relief and which are conventionally defined within the area where deviations of form and waviness are eliminated. Determined by a stylus type instrument with the ball rotating.  Compliance with Ra limits specific in ABMA Std. 10.

Waviness: The more widely spaced circumferential component of surface texture.

Grade and Tolerance - Metric (Millimeters)
Grade	Deviation from Spherical Range	Lot Diameter Variation	Allowable Ball Gage Variation	Nominal Ball Diameter Tolerance	Marking Increments	Maximum Surface Roughness 1 in Micro inches “Ra”
3	0.0008	0.0008	±0.0008	-	0.00025	0.012
5	0.00013	0.00013	±0.0013	-	0.00025	0.02
10	0.00025	0.00025	±0.0013	-	0.00025	0.025
25	0.0006	0.0006	±0.0025	-	0.00025	0.051
50	0.0012	0.0012	-	±0.0051	0.00127	0.076
100	0.0025	0.0025	-	±0.0381	-	0.127
200	0.005	0.005	-	±0.025	-	0.203
1000	0.025	0.025	-	±0.127	-	-

Grade and Tolerance - Inches
Grade	Size Range	Deviation from Spherical Range	Lot Diameter Variation	Allowable Ball Gage Variation	Nominal Ball Diameter Tolerance	Marking Increments	Maximum Surface Roughness 1 in Micro inches “Ra”
3	.006 - 2"	0.000003	0.000003	±0.00003	-	0.00001	0.5
5	.006 - 6"	0.000005	0.000005	±0.00005	-	0.00001	0.8
10	.006 - 10"	0.00001	0.000010	±0.00005	-	0.00001	1.0
25	.006 - 10"	0.000025	0.000025	±0.00010	-	0.00001	2.0
50	.006 - 10"	0.00005	0.000050	-	±0.0002	0.00005	3.0
100	.006 - 10"	0.0001	0.0001	-	±0.0005	-	5.0
200	.006 - 10"	0.0002	0.0002	-	±0.001	-	8.0
1000	.006 - 10"	0.001	0.001	-	±0.005	-	-

 

material	rockbit (s-2)	440-c	k-monel	52100 chrome	brass	bronze	aluminum	carbide	329ss	302ss	316ss	carbon	rexalloy	stellite
size	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb	# per lb
2 mm	13,824	14,123	12,785	13,824	12,785	14,226	38,734	7,245	13,775	13,679	13,679	13,775	12,302	12,302
3/32	8,190	8,368	7,575	8,190	7,575	8,429	22,949	4,292	8,161	8,104	8,104	8,161	7,289	7,289
7/64	5,158	5,269	4,770	5,158	4,770	5,308	14,452	2,703	5,140	5,104	5,104	5,140	4,590	4,590
3 mm	4,096	4,185	3,788	4,096	3,788	4,215	11,477	2,147	4,082	4,053	4,053	4,082	3,645	3,645
0.1230	3,627	3,705	3,354	3,627	3,354	3,732	10,162	1,901	3,614	3,589	3,589	3,614	3,227	3,227
0.1240	3,540	3,616	3,274	3,540	3,274	3,643	9,918	1,855	3,527	3,502	3,502	3,527	3,150	3,150
0.1245	3,497	3,573	3,234	3,497	3,234	3,599	9,799	1,833	3,485	3,460	3,460	3,485	3,112	3,112
0.1250	3,455	3,530	3,196	3,455	3,196	3,556	9,682	1,811	3,443	3,419	3,419	3,443	3,075	3,075
0.1260	3,374	3,447	3,120	3,374	3,120	3,472	9,453	1,768	3,362	3,338	3,338	3,362	3,002	3,002
0.1255	3,414	3,488	3,158	3,414	3,158	3,513	9,566	1,789	3,402	3,378	3,378	3,402	3,038	3,038
0.1265	3,334	3,406	3,083	3,334	3,083	3,431	9,341	1,747	3,322	3,299	3,299	3,322	2,967	2,967
0.1270	3,295	3,366	3,047	3,295	3,047	3,390	9,231	1,727	3,283	3,260	3,260	3,283	2,932	2,932
0.1275	3,256	3,327	3,011	3,256	3,011	3,351	9,123	1,706	3,245	3,222	3,222	3,245	2,898	2,898
0.1280	3,218	3,288	2,976	3,218	2,976	3,312	9,017	1,686	3,207	3,184	3,184	3,207	2,864	2,864
0.1285	3,181	3,249	2,942	3,181	2,942	3,273	8,912	1,667	3,169	3,147	3,147	3,169	2,831	2,831
0.1290	3,144	3,212	2,907	3,144	2,907	3,235	8,809	1,648	3,133	3,111	3,111	3,133	2,798	2,798
0.1295	3,107	3,175	2,874	3,107	2,874	3,198	8,707	1,629	3,097	3,075	3,075	3,097	2,765	2,765
0.1300	3,072	3,138	2,841	3,072	2,841	3,161	8,607	1,610	3,061	3,040	3,040	3,061	2,734	2,734
0.1305	3,037	3,102	2,808	3,037	2,808	3,125	8,508	1,591	3,026	3,005	3,005	3,026	2,702	2,702
0.1310	3,002	3,067	2,776	3,002	2,776	3,089	8,411	1,573	2,991	2,970	2,970	2,991	2,672	2,672
0.1315	2,968	3,032	2,745	2,968	2,745	3,054	8,316	1,555	2,957	2,937	2,937	2,957	2,641	2,641
0.1320	2,934	2,998	2,714	2,934	2,714	3,020	8,222	1,538	2,924	2,903	2,903	2,924	2,611	2,611
0.1325	2,901	2,964	2,683	2,901	2,683	2,986	8,129	1,520	2,891	2,871	2,871	2,891	2,582	2,582
0.1330	2,869	2,931	2,653	2,869	2,653	2,952	8,038	1,503	2,858	2,838	2,838	2,858	2,553	2,553
0.1335	2,836	2,898	2,623	2,836	2,623	2,919	7,948	1,486	2,826	2,807	2,807	2,826	2,524	2,524
0.1340	2,805	2,866	2,594	2,805	2,594	2,886	7,859	1,470	2,795	2,775	2,775	2,795	2,496	2,496
0.1345	2,774	2,834	2,565	2,774	2,565	2,854	7,772	1,454	2,764	2,745	2,745	2,764	2,468	2,468
0.1350	2,743	2,802	2,537	2,743	2,537	2,823	7,686	1,437	2,733	2,714	2,714	2,733	2,441	2,441
0.1355	2,713	2,771	2,509	2,713	2,509	2,792	7,601	1,422	2,703	2,684	2,684	2,703	2,414	2,414
3.5 mm	2,579	2,635	2,385	2,579	2,385	2,654	7,227	1,352	2,570	2,552	2,552	2,570	2,295	2,295
3.969 mm	1,769	1,807	1,636	1,769	1,636	1,820	4,956	927	1,763	1,750	1,750	1,763	1,574	1,574
9/64	2,427	2,479	2,244	2,427	2,244	2,497	6,800	1,272	2,418	2,401	2,401	2,418	2,160	2,160
0.1454	2,195	2,243	2,030	2,195	2,030	2,259	6,152	1,151	2,188	2,172	2,172	2,188	1,954	1,954
5/32	1,769	1,807	1,636	1,769	1,636	1,821	4,957	927	1,763	1,751	1,751	1,763	1,574	1,574
4 mm	1,728	1,765	1,598	1,728	1,598	1,778	4,842	906	1,722	1,710	1,710	1,722	1,538	1,538
11/64	1,329	1,358	1,229	1,329	1,229	1,368	3,724	697	1,324	1,315	1,315	1,324	1,183	1,183
3/16	1,024	1,046	947	1,024	947	1,054	2,869	537	1,020	1,013	1,013	1,020	911	911
0.1878	1,019	1,041	942	1,019	942	1,049	2,855	534	1,015	1,008	1,008	1,015	907	907
5 mm	885	904	818	885	818	910	2,479	464	882	875	875	882	787	787
5.5 mm	665	679	615	665	615	684	1,862	348	662	658	658	662	592	592
13/64	805	823	745	805	745	829	2,256	422	802	797	797	802	717	717
7/32	645	659	596	645	596	663	1,806	338	642	638	638	642	574	574
0.2187	645	659	597	645	597	664	1,808	338	643	638	638	643	574	574
0.2192	641	655	593	641	593	659	1,795	336	638	634	634	638	570	570
5.953 mm	524	536	485	524	485	539	1,469	275	522	519	519	522	467	467
5.7 mm	600	613	555	600	555	617	1,680	314	598	593	593	598	534	534
15/64	524	536	485	524	485	539	1,469	275	522	519	519	522	466	466
6 mm	512	523	474	512	474	527	1,435	268	510	507	507	510	456	456
0.2480	442	452	409	442	409	455	1,240	232	441	438	438	441	394	394
0.2490	437	447	404	437	404	450	1,225	229	436	433	433	436	389	389
1/4	432	441	399	432	399	444	1,210	226	430	427	427	430	384	384
17/64	360	368	333	360	333	371	1,009	189	359	356	356	359	320	320
7 mm	322	329	298	322	298	332	903	169	321	319	319	321	287	287
9/32	303	310	281	303	281	312	850	159	302	300	300	302	270	270
0.2815	303	309	280	303	280	311	848	159	301	299	299	301	269	269
0.2875	284	290	263	284	263	292	796	149	283	281	281	283	253	253
19/64	258	264	239	258	239	265	723	135	257	255	255	257	230	230
5/16	221	226	205	221	205	228	620	116	220	219	219	220	197	197
8 mm	216	221	200	216	200	222	605	113	215	214	214	215	192	192
21/64	191	195	177	191	177	197	535	100	190	189	189	190	170	170
11/32	166	170	154	166	154	171	466	87	166	164	164	166	148	148
9 mm	164	167	152	164	152	169	459	86	163	162	162	163	146	146
23/64	145	149	134	145	134	150	407	76	145	144	144	145	129	129
3/8	128	131	118	128	118	132	359	67	128	127	127	128	114	114
25/64	113	116	105	113	105	117	317	59	113	112	112	113	101	101
10 mm	111	113	102	111	102	114	310	58	110	109	109	110	98	98
10.4 mm	98	100	91	98	91	101	275	52	98	97	97	98	87	87
13/32	101	103	93	101	93	104	282	53	100	100	100	100	90	90
27/64	90	92	83	90	83	92	252	47	90	89	89	90	80	80
11 mm	83	85	77	83	77	86	233	44	83	82	82	83	74	74
7/16	81	82	75	81	75	83	226	42	80	80	80	80	72	72
29/64	73	74	67	73	67	75	203	38	72	72	72	72	65	65
15/32	66	67	61	66	61	67	184	34	65	65	65	65	58	58
12 mm	64	65	59	64	59	66	179	34	64	63	63	64	57	57
31/64	59	61	55	59	55	61	166	31	59	59	59	59	53	53
1/2	54	55	50	54	50	56	151	28	54	53	53	54	48	48
33/64	49	50	46	49	46	51	138	26	49	49	49	49	44	44
17/32	45	46	42	45	42	46	126	24	45	45	45	45	40	40
35/64	41	42	38	41	38	42	116	22	41	41	41	41	37	37
9/16	38	39	35	38	35	39	106	20	38	38	38	38	34	34
37/64	35	36	32	35	32	36	98	18	35	35	35	35	31	31
19/32	32	33	30	32	30	33	90	17	32	32	32	32	29	29
39/64	30	30	28	30	28	31	84	16	30	30	30	30	27	27
5/8	28	28	26	28	26	28	77	14	28	27	27	28	25	25
41/64	26	26	24	26	24	26	72	13	26	25	25	26	23	23
21/32	24	24	22	24	22	25	67	13	24	24	24	24	21	21
43/46	8	8	8	8	8	9	23	4	8	8	8	8	7	7
11/16	21	21	19	21	19	21	58	11	21	21	21	21	18	18
45/64	19	20	18	19	18	20	54	10	19	19	19	19	17	17
23/32	18	19	17	18	17	19	51	10	18	18	18	18	16	16
47/64	17	17	16	17	16	18	48	9	17	17	17	17	15	15
3/4	16	16	15	16	15	16	45	8	16	16	16	16	14	14
49/64	15	15	14	15	14	15	42	8	15	15	15	15	13	13
25/32	14	14	13	14	13	15	40	7	14	14	14	14	13	13
51/64	13	14	12	13	12	14	37	7	13	13	13	13	12	12
13/16	13	13	12	13	12	13	35	7	13	12	12	13	11	11
1 9/44	4	4	4	4	4	4	11	2	4	4	4	4	3	3
27/32	11	11	10	11	10	12	31	6	11	11	11	11	10	10
55/64	11	11	10	11	10	11	30	6	11	11	11	11	9	9
7/8	10	10	9	10	9	10	28	5	10	10	10	10	9	9
57/64	10	10	9	10	9	10	27	5	10	9	9	10	9	9
29/32	9	9	8	9	8	9	25	5	9	9	9	9	8	8
59/64	9	9	8	9	8	9	24	5	9	9	9	9	8	8
15/16	8	8	8	8	8	8	23	4	8	8	8	8	7	7
61/64	8	8	7	8	7	8	22	4	8	8	8	8	7	7
31/32	7	8	7	7	7	8	21	4	7	7	7	7	7	7
63/64	7	7	7	7	7	7	20	4	7	7	7	7	6	6
1	7	7	6	7	6	7	19	4	7	7	7	7	6	6
1 1/4	3	4	3	3	3	4	10	2	3	3	3	3	3	3
1 1/2	2	2	2	2	2	2	6	1	2	2	2	2	2	2
1 3/4	1	1	1	1	1	1	4	1	1	1	1	1	1	1
2	1	1	1	1	1	1	2	0	1	1	1	1	1	1
2 1/4	1	1	1	1	1	1	2	0	1	1	1	1	1	1
2 1/2	0	0	0	0	0	0	1	0	0	0	0	0	0	0
2 3/4	0	0	0	0	0	0	1	0	0	0	0	0	0	0
3	0	0	0	0	0	0	1	0	0	0	0	0	0	0