MAXIMUM OPERATING SPEEDS (RPM)
FOR MOUNTED POINTS*

CONDENSED OPERATING RULES FOR MOUNTED POINTS

Despite their small size, Mounted Wheels should be used with all of the safety precautions recommended for other types of abrasive grinding wheels. Each wheel should be inspected before use to make sure that the mandrel has not been bent or the wheel damaged. When mounting, the mandrel should be inserted into the collet as far as possible. The pressure exerted in the grinding operation should not be excessive.

Mounted Wheels should be operated with adequate speed to get efficient grinding action. The factors that affect the maximum safe operating speed of a particular size wheel include:

1. the size and shape of the wheel
2. the overhang (distance that the wheel is extended from the collet)
3. the diameter of the mandrel on which the wheel is mounted
4. the condition of the grinder and its collet

Refer to these tables and/or the American Safety code for maximum operating speeds. (ANSI B7.1) DO NOT EXCEED THE SPEED INDICATED! The use of abrasive wheels can cause nuisance dust. Take normal precautions to avoid exposure. WEAR FACE PROTECTION AT ALL TIMES! It is a good practice when holding hand grinders to hold the grinder down and away from the operator until full operating speed is attained and it is determined that the mounted wheel is properly mounted and running smoothly. DO NOT OPERATE A MOUNTED WHEEL WHICH IS NOT PROPERLY MOUNTED AND RUNNING TRUE! If excessive vibration is felt, stop the grinder at once and do not resume grinding until the cause is found and corrected.

MAXIMUM OPERATING SPEEDS (RPM) FOR 1/4" MANDRELS GROUP “A” AND (SELECTED) GROUP “B” SHAPES
Shape No.	Wheel Size Diam. x Thk.	1/2" Overhang & Threaded Mandrels	1"	1-1/2"	2"
			Overhang
A1	3/4 x 2-1/2	19800	16500	13120	10650
A2	1 x 1-1/4	38200	32620	25500	20620
A3	1 x 2-3/4	16100	13080	10730	8720
A4	1-1/4 x 1-1/4	30560	24750	20250	16120
A5	3/4 x 1-1/8	45000	33750	27000	21000
A6	3/4 x 1-1/8	39000	29700	24000	18970
A11	7/8 x 2	19860	15100	12000	9810
A12	11/16 x 1-1/4	48000	35250	27370	21750
A13	1-1/8 x 1-1/8	33950	32250	25500	20620
A14	11/16 x 7/8	55560	40500	30750	24370
A15	1/4 x 1-1/16	72750	47620	34500	26250
A21	1 x 1	34500	26250	21000	17250
A22	3/4 x 5/8	50930	40500	30750	24370
A23	3/4 x 1	39370	30370	24370	19500
A24	1/4 x 3/4	76500	49500	36370	27000
A25	1 x 1	35620	27370	22120	18000
A26	5/8 x 5/8	61120	46500	35250	27750
A31	1-3/8 x 1	27780	26250	21000	17250
A32	1 x 5/8	38200	38200	30000	24000
A33	1 x 1/2	38200	38200	30000	24000
A34	1-1/2 x 3/8	25470	25470	25470	21970
A35	1 x 3/8	38200	38200	31500	25500
A36	1-5/8 x 3/8	23520	23520	23520	21750
A37	1-1/4 x 1/4	30560	30560	30560	28120
A38	1 x 1	34500	26250	21000	17020
A39	3/4 x 3/4	47250	35250	27750	22120
A40	3/4 x 3/4	47250	35250	27750	22120
B41	5/8 x 5/8	61120	46500	35250	27370
B42	1/2 x 3/4	61120	46500	35250	27370
B51	7/16 x 3/4	81000	54370	42000	33000
B52	3/8 x 3/4	81000	54370	42000	33000
B61	3/4 x 5/16	50930	50930	38100	29020
B62	1/2 x 3/8	71250	47620	35020	27000
B91	1/2 x 5/8	61500	42000	31500	24000
B101	5/8 x 11/16	61120	46500	35250	27370
B102	5/8 x 1/2	61120	54370	42000	33000
B111	7/16 x 11/16	66000	46500	35250	27370
B112	3/8 x 1/2	81000	54370	42000	33000
B121	1/2 x 1/2	76390	54370	42000	33000
B131	1/2 x 1/2	61500	42000	31500	24000
B132	3/8 x 1/2	81000	54370	42000	33000
MAXIMUM OPERATING SPEEDS (RPM) FOR 1/4" MANDRELS GROUP “W” (PLAIN SHAPES)
Shape No.	Wheel Size Diam. x Thk.	1/2" Overhang & Threaded Mandrels	1"	1-1/2"	2"
			Overhang
W170	3/8 x 1/2	81000	54370	42000	33000
W175	3/8 x 3/8	71250	47620	35020	27000
W176	3/8 x 1/2	81000	54370	42000	33000
W177	3/8 x 3/4	66000	46500	32250	27370
W178	3/8 x 1	55200	40500	30000	23250
W179	3/8 x 1-1/4	45750	33750	25720	19720
W183	1/2 x 1/4	76390	54750	40500	31120
W184	1/2 x 3/8	71250	47620	35020	27000
W185	1/2 x 1/2	61500	42000	31500	24000
W186	1/2 x 3/4	51000	36370	27750	21220
W187	1/2 x 1	40500	30000	24000	18750
W188	1/2 x 1-1/2	30370	24000	18900	15000
W189	1/2 x 2	24000	18750	15000	12150
W192	5/8 x 1/4	61120	51750	38400	29770
W193	5/8 x 3/8	61120	45000	33370	25870
W194	5/8 x 1/2	56400	39750	29400	22720
W195	5/8 x 3/4	46500	32400	24900	19720
W196	5/8 x 1	35250	27000	21300	16870
W197	5/8 x 2	21000	16500	12900	10870
W198	5/8 x 2-1/2	16500	12900	10870	8700
W201	3/4 x 1/4	50930	50930	38100	29020
W202	3/4 x 3/8	50930	44100	32400	25120
W203	3/4 x 1/2	50930	36370	27750	21750
W204	3/4 x 3/4	42750	30750	23250	18000
W205	3/4 x 1	34500	25870	19500	15000
W206	3/4 x 1-1/4	28720	21520	17020	13500
W207	3/4 x 1-1/2	24000	18520	14620	12000
W208	3/4 x 2	18750	15370	12000	9900
W209	3/4 x 2-1/2	15000	12150	10500	8400
W211	7/8 x 1/8	43650	43650	42900	33000
W212	7/8 x 1/4	43650	43650	35100	27600
W213	7/8 x 3/8	43650	40870	29400	23400
W214	15/16 x 1/4	38200	38200	33750	26250
W215	1 x 1/8	38200	38200	38200	33750
W216	1 x 1/4	38200	38200	33750	26250
W217	1 x 3/8	38200	38200	28500	22500
W218	1 x 1/2	38200	32770	24900	19500
W219	1 x 3/4	35100	24520	18750	15000
W220	1 x 1	25500	19120	15750	12370
W221	1 x 1-1/2	19120	14620	12000	10500
W222	1 x 2	15900	12370	9750	8620
W223	1 x 2-1/2	12370	9900	8620	6900
W224	1 x 3	12940	6600	5050	4700
W225	1-1/4 x 1/4	30560	30560	30560	24000
W226	1-1/4 x 3/8	30560	30560	26250	20100
W227	1-1/4 x 1/2	30560	29620	22650	18000
W228	1-1/4 x 3/4	30520	22500	17850	14250
W229	1-1/4 x 1	24000	18750	15370	12000
W230	1-1/4 x 1-1/4	20400	15900	12750	10500
W231	1-1/4 x 1-1/2	17620	13500	10650	9000
W232	1-1/4 x 2	14250	10650	9000	7500
W235	1-1/2 x 1/4	25470	25470	25470	22720
W236	1-1/2 x 1/2	25470	25470	21750	17250
W237	1-1/2 x 1	22500	17620	13270	10870
W238	1-1/2 x 1-1/2	15600	12000	9750	8250
W239	1-1/2 x 2	12750	9900	8000	6400
W241	1-1/2 x 3	12750	6600	5050	4700
W242	2 x 1	19100	15950	11750	10000
W243	2 x 1-1/2	14500	12750	9800	7800
W244	2 x 2	11750	10500	7500	6200
MAXIMUM OPERATING SPEEDS (RPM) FOR 1/8" MANDRELS GROUP “B” SHAPES
Shape No.	Wheel Size Diam. x Thk.	1/2" Overhang & Threaded Mandrels	1"	1-1/2"	2"
			Overhang
B41	5/8 x 5/8	33750	23250	17620	13650
B42	1/2 x 3/4	33750	23250	17620	13650
B43	1/4 x 5/16	81370	51000	34120	24000
B44	7/32 x 3/8	68400	42370	28870	20850
B45	3/16 x 5/16	104250	61870	44620	30900
B46	1/8 x 5/16	105000	64500	46650	32400
B47	1/8 x 5/32	105000	64500	46650	32400
B51	7/16 x 3/4	45370	28500	21000	15900
B52	3/8 x 3/4	45370	28500	21000	15900
B53	1/4 x 5/8	60000	38020	26250	18750
B54	1/4 x 1/2	60000	38020	26250	18750
B55	1/8 x 1/4	105000	64500	46650	32400
B61	3/4 x 5/16	38250	24370	17400	13270
B62	1/2 x 3/8	41020	26400	19500	15000
B63	1/4 x 3/16	92400	57370	39370	27900
B64	1/4 x 1/16	105000	64500	46650	32400
B65	1/8 x 1/8	105000	64500	46650	32400
B70	3/4 x 1/8	50930	41250	27750	20400
B71	5/8 x 1/8	61120	48000	31500	22650
B72	1/2 x 1/8	73500	43650	29100	20770
B73	1/2 x 1/8	73500	43650	29100	20770
B74	7/32 x 3/32	105000	64500	46650	32400
B81	3/4 x 3/16	50930	41250	27750	20400
B82	1/2 x 1/4	76390	51000	34120	24000
B83	3/8 x 3/16	87600	53250	35250	24750
B84	5/16 x 3/16	105000	64500	46650	32400
B90	1/2 x 1/2	34500	22500	16870	13120
B91	1/2 x 5/8	34500	22500	16870	13120
B92	1/4 x 1/4	81370	51000	34120	24000
B93	3/16 x 3/16	105000	64500	46650	32400
B94	11/64 x 3/32	105000	64500	46650	32400
B95	1/8 x 3/16	105000	64500	46650	32400
B96	1/8 x 1/4	105000	64500	46650	32400
B97	1/8 x 3/8	105000	64500	46650	32400
B98	3/32 x 1/4	105000	64500	46650	32400
B101	5/8 x 11/16	33750	23250	17620	13650
B102	5/8 x 1/2	45370	28500	21000	15900
B103	5/8 x 1/4	61120	41250	27750	20400
B104	5/16 x 3/8	68400	42370	28870	20850
B105	1/4 x 1/4	104250	61870	44620	30900
B106	1/8 x 7/64	105000	64500	46650	32400
B111	7/16 x 11/16	33750	23250	17620	13650
B112	3/8 x 1/2	45370	28500	21000	15900
B113	1/4 x 1/4	81370	51000	34120	24000
B114	7/32 x 3/8	68400	42370	28870	20850
B115	3/32 x 1/8	105000	64500	46650	32400
B121	1/2 x 1/2	45370	28500	21000	15900
B122	3/8 x 3/8	61650	37720	27000	19870
B123	3/16 x 3/16	104250	61820	44620	30900
B124	1/8 x 1/8	105000	64500	46650	32400
B125	1/4 x 1/4	61650	37720	27000	19870
B131	1/2 x 1/2	34500	22500	16870	13120
B132	3/8 x 1/2	45370	28500	21000	15900
B133	3/8 x 3/8	54000	33000	24150	18000
B134	5/16 x 3/8	61650	37720	27000	19870
B135	1/4 x 1/2	60000	38020	26250	18750
B136	1/4 x 5/16	77250	45920	30900	22500
MAXIMUM OPERATING SPEEDS (RPM) FOR 1/8" MANDRELS GROUP “W” SHAPES
Shape No.	Wheel Size Diam. x Thk.	1/2" Overhang & Threaded Mandrels	1"	1-1/2"	2"
			Overhang
W141	3/32 x 5/32	105000	64500	46650	32400
W142	3/32 x 1/4	105000	64500	46650	32400
W143	1/8 x 1/8	105000	64500	46650	32400
W144	1/8 x 1/4	105000	64500	46650	32400
W145	1/8 x 3/8	105000	64500	46650	32400
W146	1/8 x 1/2	105000	64500	46650	32400
W149	5/32 x 1/4	105000	64500	46650	32400
W151	3/16 x 1/8	105000	64500	46650	32400
W152	3/16 x 1/4	105000	64500	46650	32400
W153	3/16 x 3/8	80850	52500	37500	26250
W154	3/16 x 1/2	70500	45600	31500	21970
W157	1/4 x 1/16	123000	65625	47770	33150
W158	1/4 x 1/8	105000	64500	46650	32400
W159	1/4 x 3/16	92400	57370	39370	27900
W160	1/4 x 1/4	81370	51000	34120	24000
W161	1/4 x 5/16	77250	45970	30900	22500
W162	1/4 x 3/8	68400	42370	28870	20850
W163	1/4 x 1/2	60000	38020	26250	18750
W164	1/4 x 3/4	45900	30000	21750	15900
W165	5/16 x 1/16	107400	62470	41250	29250
W166	5/16 x 1/8	96970	57000	35620	25120
W167	5/16 x 1/4	75000	45750	31120	22500
W168	5/16 x 5/16	68400	41770	28650	21000
W169	5/16 x 3/8	61650	37720	27000	19870
W170	5/16 x 1/2	52500	33000	23020	16650
W171	5/16 x 3/4	37120	25500	18750	14620
W172	3/8 x 1/16	99370	59250	41020	29250
W173	3/8 x 1/8	87600	53250	35250	24750
W174	3/8 x 1/4	69000	41250	27750	20400
W175	3/8 x 3/8	54000	33000	24150	18000
W176	3/8 x 1/2	45370	28500	21000	15900
W177	3/8 x 3/4	33750	23250	17620	13650
W178	3/8 x 1	26250	18750	14250	10870
W181	1/2 x 1/16	76390	55500	36750	25500
W182	1/2 x 1/8	73500	43650	29100	20770
W183	1/2 x 1/4	51750	31870	22500	17250
W184	1/2 x 3/8	41020	26400	19500	15000
W185	1/2 x 1/2	34500	22500	16870	13120
W186	1/2 x 3/4	26250	17400	12750	9750
W187	1/2 x 1	20620	13870	10120	7870
W190	5/8 x 1/16	61120	48000	31500	22650
W191	5/8 x 1/8	58870	34500	25120	18900
W192	5/8 x 1/4	43120	27370	19870	15220
W193	5/8 x 3/8	32250	23020	16500	12520
W194	5/8 x 1/2	29400	19120	13500	10500
W195	5/8 x 3/4	22120	14250	10120	7650
W196	5/8 x 1	17620	11620	8100	6150
W199	3/4 x 1/16	50930	44770	30000	21750
W200	3/4 x 1/8	50930	33520	23850	17850
W201	3/4 x 1/4	38250	24370	17400	13270
W202	3/4 x 3/8	30600	19500	13500	10120
W203	3/4 x 1/2	25500	15900	10870	8250
W204	3/4 x 3/4	18900	12000	8400	6220
W210	7/8 x 1/16	43650	35250	25720	18900
W211	7/8 x 1/8	43650	27900	20400	15820
W212	7/8 x 1/4	33750	20400	14400	11020
W213	7/8 x 3/8	27000	16870	11250	8250
W214	15/16 x 1/4	30520	18600	12750	9520
W215	1 x 1/8	38200	24900	18800	13870
W216	1 x 1/4	30520	18600	12750	9520
MAXIMUM OPERATING SPEEDS (RPM) FOR 3/8" MANDRELS GROUP “W” (SELECTED LARGER PLAIN SHAPES)
Shape No.	Wheel Size Diam. x Thk.	1/2" Overhang & Threaded Mandrels	1"	1-1/2"	2"
			Overhang
W223	1 x 2-1/2	24740	19800	17240	13800
W231	1-1/4 x 1-1/2	30560	27000	21300	18000
W232	1-1/4 x 2	28500	21300	18000	15000
W238	1-1/2 x 1-1/2	25470	24000	19500	16500
W239	1-1/2 x 2	25470	19800	16000	12800
W240	1-1/2 x 2-1/2	21000	16800	13600	11000
W241	1-1/2 x 3	18000	14500	12000	9600
W242	2 x 1	19100	19100	19100	19100
W243	2 x 1-1/2	19100	19100	19100	15600
W244	2 x 2	19100	19100	15000	12400
W245	2 x 2-1/2	19100	14500	12800	10600
W246	2 x 3	16500	13500	11200	9200

*Courtesy of the Grinding Wheel Institute.