Hard Fiber Squares | McMaster-Carr

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System of Measurement

Thickness

Width

Length

Shape

Performance

Highly Electrically Insulating

Highly Impact Resistant

Flexibility

Color

Backing Type

Texture

Hardness Rating

Dielectric Strength

195 V/mil to 215 V/mil

Maximum Temperature

Clarity

For Use Outdoors

Tensile Strength

9,000 psi to 21,000 psi

10,000 psi to 21,000 psi

Not Rated

Minimum Temperature

Not Rated

Military Specification

MIL-F-1148

MIL-F-10336

MIL-I-695

Reinforcement Material

Cotton Fabric

Water Absorption

63%

63% to 66%

Export Control Classification Number (ECCN)

EAR99

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

REACH

Compliant

RoHS

Compliant

DFARS Specialty Metals

Exempt

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62 Products

About Composites

Compare our offering of composites to find the right material for you.

Easy-Machine Hard Fiber Sheets

Also known as vulcanized fiber, these hard fiber sheets can be readily machined and punched into custom parts. They're constructed from lightweight cotton fabric that's been chemically treated to make them hard and dense. Use hard fiber to make gears and bushings.

										12" Wide × 12" Long		24" Wide × 39" Long		39" Wide × 48" Long
Thk.	Thk. Tolerance	Tensile Strength, psi	Hardness	Mil. Spec.	Flammability Rating	Color	Max. Temp., ° F	Impact Strength, ft·lbf/in	For Use Outdoors		Each		Each		Each
0.02"	-0.002" to 0.002"	9,000 to 21,000	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	1.8 to 2.5	No	8490K13	000000	8490K23	000000	8490K33	000000
0.03"	-0.003" to 0.003"	9,000 to 21,000	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	1.8 to 2.5	No	8490K14	00000	8490K24	00000	8490K34	00000
1/16"	-0.005" to 0.005"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K73	00000	8652K83	00000	8652K93	000000
3/32"	-0.007" to 0.007"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K74	00000	8652K84	000000	8652K94	000000
1/8"	-0.015" to 0.015"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K75	00000	8652K85	000000	8652K95	000000
3/16"	-0.015" to 0.015"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K76	00000	8652K86	000000	8652K96	000000
1/4"	-0.015" to 0.015"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K77	00000	8652K87	000000	8652K97	000000
3/8"	-0.02" to 0.02"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K78	000000	8652K88	000000	8652K98	00000000
1/2"	-0.025" to 0.025"	9,000 to 21,000	Rockwell R80 (Hard)	MIL-F-10336, MIL-F-1148	UL 94 HB	Gray	235	1.8 to 2.5	No	8652K79	000000	8652K89	000000	8652K99	00000000

Electrically Insulating Hard Fiber

Widely known as fishpaper and vulcanized fiber, these thin sheets offer better electrical insulation than standard hard fiber sheets. They are constructed from lightweight cotton fabric that's been chemically treated to make it hard and dense.

										6" Wide × 12" Long		12" Wide × 12" Long		24" Wide × 39" Long		39" Wide × 48" Long		39" Wide × 60" Long
Thk.	Thk. Tolerance	Tensile Strength, psi	Hardness	Mil. Spec.	Flammability Rating	Color	Max. Temp., ° F	Impact Strength, ft·lbf/in	For Use Outdoors		Each		Each		Each		Each		Each
0.005"	-0.001" to 0.001"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K101	00000	8490K15	00000	8490K25	000000	8490K35	000000	———	0
0.01"	-0.001" to 0.001"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K102	0000	8490K11	0000	8490K21	00000	8490K31	00000	8490K103	000000
0.015"	-0.002" to 0.002"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K104	0000	8490K12	0000	8490K22	00000	8490K32	00000	8490K105	00000
0.02"	-0.002" to 0.002"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K106	0000	8490K37	00000	8490K38	00000	8490K39	00000	———	0
0.025"	-0.003" to 0.003"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K107	00000	8490K16	00000	8490K26	00000	8490K36	000000	———	0
0.03"	-0.003" to 0.003"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K108	00000	8490K51	00000	8490K52	00000	8490K53	00000	———	0
0.04"	-0.004" to 0.004"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K109	00000	8490K54	00000	8490K55	000000	———	0	———	0
0.045"	-0.005" to 0.005"	Not Rated	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	8490K111	00000	8490K57	00000	8490K58	000000	———	0	———	0
0.062"	-0.007" to 0.007"	10,000 to 21,000	Rockwell R70 (Hard)	MIL-I-695	UL 94 HB	Gray	235	2.5	No	———	0	8490K61	00000	8490K62	000000	8490K63	000000	———	0