Machinist Parallels | McMaster-Carr

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106 Products

Sets of Parallels

Keep multiple sizes of matched pairs on hand in one protective case. These parallels elevate, support, and align workpieces in machining, grinding, and inspection setups. They are precision ground to ensure accurate positioning in vises while providing additional clearance for cutting tools. Durable and wear resistant, parallels are made of hardened steel. They’re a rugged solution for shop-floor setups and heavy duty applications. To use, place a parallel against each vise jaw and rest the workpiece on top. You can also use them as reference surfaces for measurement and alignment.

Inch


Straight	Wave

Wave—These parallels make continuous contact that's spread across multiple points. They support thin, irregular, and soft workpieces without damaging them. The wave shape also creates space for chips and debris to fall away.

2 Precision-Ground Sides—Precision ground on the top and bottom edges.

4 Precision-Ground Sides—Precision ground on the top edge, bottom edge, and both faces.

					Tolerance
	No. of Pairs	Lg.	Thk.	Ht.	Ht.	Parallel	Material	Container Type		Each
Straight







				2 Precision-Ground Sides

				4	6"	3/16"	1", 1 1/4", 1 1/2", 1 3/4"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Wood Case	8644A21	000000


				4	6"	1/2"	1", 1 1/4", 1 1/2", 1 3/4"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Plastic Case	8644A23	000000
				7	6"	1/2"	7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 5/8", 1 3/4"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Plastic Case	8644A32	000000
				8	6"	1/4"	3/4", 7/8", 1", 1 1/8", 1 3/8", 1 1/2", 1 5/8", 1 3/4"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Plastic Case	8644A43	000000
				9	6"	1/4"	3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	Wood Case	8642A67	000000
				9	6"	1/4"	15/16", 1", 1 1/16", 1 1/8", 1 3/16", 1 1/4", 1 5/16", 1 3/8", 1 7/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	Wood Case	8642A68	000000
				10	4"	1/8"	1/2", 5/8", 3/4", 7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 1/2", 1 5/8"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Wood Case	86425A31	00000
				10	6"	1/8"	1/2", 5/8", 3/4", 7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 1/2", 1 5/8"	-0.001" to 0.001"	-0.0004" to 0.0004"	Hardened Steel	Plastic Case	86425A65	000000
				20	6"	1/32"	1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8", 15/16", 1", 1 1/16", 1 1/8", 1 3/16", 1 1/4", 1 5/16", 1 3/8", 1 7/16", 1 1/2", 1 9/16", 1 5/8", 1 11/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	Plastic Case	8644A7	00000
				22	6"	1/4"	1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8", 15/16", 1", 1 1/16", 1 1/8", 1 3/16", 1 1/4", 1 5/16", 1 3/8", 1 7/16", 1 1/2", 1 9/16", 1 5/8", 1 11/16", 1 3/4", 1 13/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	Wood Case	8642A61	00000000




						4 Precision-Ground Sides

						9	6"	1/4"	3/4", 7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 1/2", 1 5/8", 1 3/4"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Plastic Case	86425A46	000000


						9	8"	1/4"	1", 1 1/4", 1 3/8", 1 1/2", 1 5/8", 1 3/4", 1 7/8", 2", 2 1/8"	-0.0001" to 0.0001"	-0.0001" to 0.0001"	Hardened Steel	Plastic Case	8642A11	000000
						10	6"	1/32"	1/2", 5/8", 3/4", 7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 1/2", 1 5/8"	-0.0001" to 0.0001"	-0.0001" to 0.0001"	Hardened Steel	Plastic Case	86425A51	000000
						10	6"	1/8"	1/2", 5/8", 3/4", 7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 1/2", 1 5/8"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	Plastic Case	86425A55	000000


						Wave







										2 Precision-Ground Sides

										9	4 1/4"	1/8"	1/2", 5/8", 3/4", 7/8", 1", 1 1/8", 1 1/4", 1 3/8", 1 1/2"	-0.0002" to 0.0002"	-0.0002" to 0.0002"	Hardened Steel	Wood Case	86425A81	000000

Metric

Straight

2 Precision-Ground Sides—Precision ground on the top and bottom edges.

					Tolerance, mm
	No. of Pairs	Lg., mm	Thk.	Ht.	Ht.	Parallel	Material	Container Type		Each
Straight







				2 Precision-Ground Sides

				20	100	2 mm 3 mm 4 mm 5 mm 6 mm	5 mm, 10 mm, 15 mm, 20 mm 6 mm, 11 mm, 16 mm, 21 mm 7 mm, 12 mm, 17 mm, 22 mm 8 mm, 13 mm, 18 mm, 23 mm 9 mm, 14 mm, 19 mm, 24 mm	-0.1 to 0.1	-0.01 to 0.01	Hardened Steel	Wood Stand	8642A71	000000000

Parallels

Elevate, support, and align workpieces in machining, grinding, and inspection setups. These parallels are precision ground to ensure accurate positioning in vises while providing additional clearance for cutting tools. Made of hardened steel, they withstand the wear and tear of shop-floor setups and heavy duty applications. To use, place a parallel against each vise jaw and rest the workpiece on top. You can also use these parallels as reference surfaces for measurement and alignment.

2 Precision-Ground Sides—Precision ground on the top and bottom edges.

4 Precision-Ground Sides—Precision ground on the top edge, bottom edge, and both faces.

				Tolerance
	Lg.	Thk.	Ht.	Ht.	Parallel	Material		Pair
Starrett Parallels







				4 Precision-Ground Sides

				6"	1/4"	1/2"	-0.0002" to 0.0002"	-0.00005" to 0.00005"	Hardened Steel	2259A12	0000000


				6"	1/4"	3/4"	-0.0002" to 0.0002"	-0.00005" to 0.00005"	Hardened Steel	2259A14	000000
				6"	3/8"	3/4"	-0.0002" to 0.0002"	-0.00005" to 0.00005"	Hardened Steel	2259A17	000000
				6"	1/2"	1"	-0.0002" to 0.0002"	-0.00005" to 0.00005"	Hardened Steel	2259A21	000000


				Other Parallels







								2 Precision-Ground Sides

								6"	1/32"	1/2"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A211	00000


								6"	1/32"	9/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A212	00000
								6"	1/32"	5/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A213	00000
								6"	1/32"	11/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A214	00000
								6"	1/32"	3/4"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A215	00000
								6"	1/32"	13/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A216	00000
								6"	1/32"	7/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A217	00000
								6"	1/32"	15/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A221	00000
								6"	1/32"	1"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A222	00000
								6"	1/32"	1 1/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A223	00000
								6"	1/32"	1 1/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A224	00000


								6"	1/32"	1 3/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A225	00000
								6"	1/32"	1 1/4"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A226	00000
								6"	1/32"	1 5/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A227	00000
								6"	1/32"	1 3/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A228	00000
								6"	1/32"	1 7/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A231	00000
								6"	1/32"	1 1/2"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A232	00000
								6"	1/32"	1 9/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A233	00000
								6"	1/32"	1 5/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A234	00000
								6"	1/32"	1 11/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A235	00000
								6"	1/8"	1/2"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A511	00000


								6"	1/8"	5/8"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A512	00000
								6"	1/8"	3/4"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A513	00000
								6"	1/8"	7/8"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A514	00000
								6"	1/8"	1"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A515	00000
								6"	1/8"	1 1/8"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A516	00000
								6"	1/8"	1 1/4"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A517	00000
								6"	1/8"	1 3/8"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A518	00000
								6"	1/8"	1 1/2"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A519	00000
								6"	1/8"	1 5/8"	-0.001" to 0.001"	-0.0002" to 0.0002"	Hardened Steel	8642A521	00000
								6"	1/4"	3/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A31	00000


6"	1/4"							7/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A311	00000
6"	1/4"							1/2"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A32	00000
6"	1/4"							9/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A33	00000
6"	1/4"	5/8"						-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A331	00000
6"	1/4"	11/16"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A332	00000
6"	1/4"	3/4"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A34	00000
6"	1/4"	13/16"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A341	00000
6"	1/4"	7/8"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A35	00000
6"	1/4"	15/16"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A351	00000
6"	1/4"	1"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A36	00000


6"	1/4"	1 1/16"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A37	00000
6"	1/4"	1 1/8"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A38	00000
6"	1/4"	1 3/16"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A39	00000
6"	1/4"	1 1/4"	-0.001" to 0.001"					-0.0001" to 0.0001"	Hardened Steel	8642A4	00000
6"	1/4"	1 5/16"	-0.001" to 0.001"	-0.0001" to 0.0001"				Hardened Steel	8642A401	00000
6"	1/4"	1 3/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel			8642A41	00000
6"	1/4"	1 7/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel			8642A411	00000
6"	1/4"	1 1/2"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel			8642A42	00000
6"	1/4"	1 9/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel			8642A43	00000
6"	1/4"	1 5/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A44		00000
6"	1/4"	1 11/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A441	00000
6"	1/4"	1 3/4"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A45	00000
6"	1/4"	1 13/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A46	00000
6"	1/4"	1 7/8"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A47	00000
6"	1/4"	1 15/16"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A48	00000
6"	1/4"	2"	-0.001" to 0.001"	-0.0001" to 0.0001"	Hardened Steel	8642A49	00000



		4 Precision-Ground Sides

		12"	3/4"	1"	-0.0004" to 0.0004"	-0.0002" to 0.0002"	Hardened Steel	2259A28	000000


		12"	1"	2"	-0.0004" to 0.0004"	-0.0002" to 0.0002"	Hardened Steel	2259A33	000000

Adjustable Parallels

Instead of keeping an assortment of parallels on hand, adjust these two-piece tools to your exact height requirements. Loosen the screw and slide the pieces in and out. When the desired height is achieved, tighten the screw. Parallels are precision ground on the top and bottom edges and are often used in pairs. Place a parallel against each vise jaw and rest your workpiece on top to raise it within the vise and allow more clearance for cutting tools.

2 Precision-Ground Sides—Precision ground on the top and bottom edges.

	Parallel Tolerance	Material		Each
Starrett Parallels







	2 Precision-Ground Sides

	1 3/4"	9/32"	3/8" to 1/2"	0.0005"	Steel	2211A11	0000000


	2 1/8"	9/32"	1/2" to 11/16"	0.0005"	Steel	2211A12	000000
	2 11/16"	9/32"	11/16" to 15/16"	0.0007"	Steel	2211A13	000000
	3 9/16"	9/32"	15/16" to 1 5/16"	0.0007"	Steel	2211A14	000000
	4 3/16"	9/32"	1 5/16" to 1 3/4"	0.0009"	Steel	2211A15	000000
	5 1/16"	9/32"	1 3/4" to 2 1/4"	0.0009"	Steel	2211A16	000000

Milling-Machine Vise Jaws with Changeable Parallels

Quickly move parallels in and out of these jaws and raise your workpiece within the vise. Choose jaws and the mating pair or set of parallels. Mount jaws to the vise, slide the parallels in place, and then rest your workpiece on top to allow more clearance for cutting tools.

Parallels

	Jaw				Steel Jaw
	Wd.	Ht.	Thk.	Thk. Tolerance		Pair
Flat Jaw



		4"	1"	0.118"	-0.005" to 0.005"	1005N17	000000


		6"	1"	0.118"	-0.005" to 0.005"	1005N19	00000
		6"	1 1/4"	0.118"	-0.005" to 0.005"	1005N21	00000
		6"	1 1/2"	0.118"	-0.005" to 0.005"	1005N22	00000

Sets of Parallels

	Jaw					Steel Jaw
	Wd.	Ht.	Thk.	Thk. Tolerance	No. of Pairs		Each
Flat Jaw



		4"	1/2", 3/4", 1", 1 1/8", 1 3/16"	0.118"	-0.005" to 0.005"	5	1005N15	0000000


		6"	3/4", 1", 1 1/8", 1 1/2", 1 5/8"	0.118"	-0.005" to 0.005"	5	1005N14	000000

Granite Inspection Parallels

Support and align workpieces for precise measuring and inspecting. Made of black granite, these inspection parallels won’t rust or warp from temperature changes, and they won’t scratch surfaces. Unlike metal inspection parallels, they’re also nonmagnetic, so they won’t interfere with sensitive electronic equipment. Made in pairs, these inspection parallels are precision ground to tight tolerances for matching flat surfaces on two or four sides. They come with a certificate traceable to NIST confirming their accuracy.

2 Precision-Ground Sides—Inspection parallels with 2 precision-ground sides have a tight parallel tolerance on the top and bottom edges.

4 Precision-Ground Sides—Inspection parallels with 4 precision-ground sides have a tight parallel tolerance on the top edge, bottom edge, and both faces.

Inspection-Grade A Plate—Inspection Grade A inspection parallels are used for general inspections and quality-control work. They’re slightly less precise than Grade AA ones.

Laboratory-Grade AA Plate—Laboratory Grade AA inspection parallels have the tightest tolerance for the highest level of accuracy. They’re best for inspections and quality-control work in calibration labs.

						Inspection-Grade A Plate			Laboratory-Grade AA Plate
	Lg.	Thk.	Ht.	Material	Certificate Type	Parallel Tolerance		Pair	Parallel Tolerance		Pair
Sold as Matched Pair







				2 Precision-Ground Sides

				6"	3/4"	1"	Black Granite	Accuracy Certificate Traceable to NIST	0.0001"	7296N13	0000000	0.00005"	7296N11	0000000


				12"	1"	2"	Black Granite	Accuracy Certificate Traceable to NIST	0.0001"	7296N14	000000	0.00005"	7296N12	000000




						4 Precision-Ground Sides

						6"	3/4"	1"	Black Granite	Accuracy Certificate Traceable to NIST	0.0001"	7296N17	000000	0.00005"	7296N15	000000


						12"	1"	2"	Black Granite	Accuracy Certificate Traceable to NIST	0.0001"	7296N18	000000	0.00005"	7296N16	000000

Sets of Adjustable Parallels

Adjust these two-piece parallels to your exact height requirements. Loosen the one or two screws and slide the pieces in and out. When the desired height is achieved, tighten the screws. Parallels are precision ground and often used in pairs. Place a parallel against each vise jaw and rest your workpiece on top to raise it within the vise, allowing more clearance for cutting tools. Parallels also function as adjustable gauges for layout, setup, and inspection tasks.

Inch

2 Precision-Ground Sides—Precision ground on the top and bottom edges.

4 Precision-Ground Sides—Precision ground on the top edge, bottom edge, and both faces.

	Material	Container Type		Each
Starrett Parallels







	2 Precision-Ground Sides

	4	One 3/8" to 1/2" High Parallel (1 3/4" Length)—±0.001" Tolerance One 1/2" to 11/16" High Parallel (2 1/8" Length)—±0.001" Tolerance One 11/16" to 15/16" High Parallel (2 11/16" Length)—±0.001" Tolerance One 15/16" to 1 5/16" High Parallel (3 9/16" Length)—±0.001" Tolerance	9/32"	Steel	Plastic Pouch	2211A21	0000000


	6	One 3/8" to 1/2" High Parallel (1 3/4" Length)—±0.001" Tolerance One 1/2" to 11/16" High Parallel (2 1/8" Length)—±0.001" Tolerance One 11/16" to 15/16" High Parallel (2 11/16" Length)—±0.001" Tolerance One 15/16" to 1 5/16" High Parallel (3 9/16" Length)—±0.001" Tolerance One 1 5/16" to 1 3/4" High Parallel (4 3/16" Length)—±0.001" Tolerance One 1 3/4" to 2 1/4" High Parallel (5 1/16" Length)—±0.001" Tolerance	9/32"	Steel	Plastic Pouch	2211A22	00000000


	Other Parallels







					4 Precision-Ground Sides

					6	One 3/8" to 1/2" High Parallel (6" Length)—0.0005" Tolerance One 1/2" to 11/16" High Parallel (6" Length)—0.0005" Tolerance One 11/16" to 15/16" High Parallel (6" Length)—0.0006" Tolerance One 15/16" to 1 15/16" High Parallel (6" Length)—0.0006" Tolerance One 1 5/16" to 1 3/4" High Parallel (6" Length)—0.0009" Tolerance One 1 3/4" to 2 1/4" High Parallel (6" Length)—0.0009" Tolerance	1/8"	Steel	Plastic Pouch	8292N12	000000

Parallels for Magnetic Workholding

Use with magnetic workholding chucks and plates to extend their holding power above the working surface. These parallels are laminated with _1/16"-thin layers of iron and stainless steel for a strong, consistent hold. Compared to parallels made from aluminum or brass, these are harder and more dent resistant, so they hold their shape over time. Each layer is entirely fused together with copper brazing, so you can machine these parallels without the layers separating. Note: Parallels are not magnetic on their own.

Sold as Matched Pair—Manufactured and ground together to ensure they are parallel and square to each other with a tolerance of 0.0002".

4 Precision-Ground Sides—Precision ground on the top edge, bottom edge, and both faces.

							Sold Individually		Sold as Matched Pair
				Tolerance
	Lg.	Thk.	Ht.	Ht.	Parallel	Material		Each		Pair
4 Precision-Ground Sides



		6"	1"	2"	-0.005" to 0.005"	0.0002"	Copper-Brazed Iron, Copper-Brazed Stainless Steel	8235N11	0000000	8235N21	0000000


		8"	1"	4"	-0.005" to 0.005"	0.0002"	Copper-Brazed Iron, Copper-Brazed Stainless Steel	8235N12	000000	8235N22	00000000