Keys · DIN 6885 / ISO 773 · Application guide

What Are Parallel Keys Used For?

Parallel Keys are selected when an assembly calls for transmitting torque between a shaft and a hub. This application guide to the DIN 6885 / ISO 773 type covers concrete end-uses, the specification checklist, correct installation, and where an alternative fastener performs better. Stocked across roughly M68 to M440500, they cover heavy and structural work.

Typical Applications for Parallel Keys

The most common settings where these are specified:

Gearboxes & motors: transmitting torque from a shaft to a hub.
Pumps & fans: driving rotating components without slip.
General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.

How to Specify Parallel Keys for Your Application

Size: Match the nominal size to the mating thread or hole. This product spans M68–M440500; check the full table below for the exact dimensions of each size.
Material: Choose the material and finish for the service environment — plated steel for general use, stainless for corrosion resistance.
Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
Standard: This product is supplied to DIN 6885 / ISO 773. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Where Parallel Keys Are Not the Right Choice

Not for very high reversing torque without an interference fit, and not as an axial retainer.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

Request a Quote

Set the size and options in the drawing above, then send the exact configuration straight to this form.

Category Type Standard Thread size Material Finish

Dimensions & Specifications (DIN 6885 / ISO 773)

Shaft diameter range (mm)	Key width b (mm)	Key height h (mm)	Key length range (mm)	Shaft groove depth t1 (mm)	Hub groove depth t2 (mm)	Reference standard	Notes
6~8	2	2	6~20	1.2	1.0	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
8~10	3	3	6~36	1.8	1.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
10~12	4	4	8~45	2.5	1.8	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
12~17	5	5	10~56	3.0	2.3	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
17~22	6	6	14~70	3.5	2.8	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
22~30	8	7	18~90	4.0	3.3	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
30~38	10	8	22~110	5.0	3.3	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
38~44	12	8	28~140	5.0	3.3	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
44~50	14	9	36~160	5.5	3.8	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
50~58	16	10	45~180	6.0	4.3	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
58~65	18	11	50~200	7.0	4.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
65~75	20	12	56~220	7.5	4.9	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
75~85	22	14	63~250	9.0	5.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
85~95	25	14	70~280	9.0	5.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
95~110	28	16	80~320	10.0	6.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
110~130	32	18	90~360	11.0	7.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
130~150	36	20	100~400	12.0	8.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
150~170	40	22	100~400	13.0	9.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
170~200	45	25	110~450	15.0	10.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
200~230	50	28	125~500	17.0	11.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
230~260	56	32	140~500	20.0	12.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
260~290	63	32	160~500	20.0	12.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
290~330	70	36	180~500	22.0	14.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
330~380	80	40	200~500	25.0	15.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
380~440	90	45	220~500	28.0	17.4	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square
440~500	100	50	250~500	31.0	19.5	DIN 6885 type A / ISO 773	Type A round ends; B square ends; C one round one square

Frequently Asked Questions

What material should Parallel Keys be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Are Parallel Keys made to a recognized standard?

Yes — they are manufactured to DIN 6885 / ISO 773, so dimensions are interchangeable between suppliers when you quote the standard on your order.