Key-Type Core Contact Slip Shaft

Key Differential Friction Shaft

Key slip shafts use rectangular metal or rubber keys to expand and contact the core, providing controlled core engagement and differential winding torque for slitting and rewinding applications. Also known as: key slip shaft, key-type friction shaft.

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Key slip shaft with long segmented body and stepped ends

Key-Type Winding Structure

Rectangular metal or rubber keys for core engagement

Suitable for 3-inch and 6-inch winding cores, especially rubber and aluminum cores that require key-type core contact.

Configured with key-type slip rings using rectangular metal keys or rectangular rubber keys.
Available for center-air and side-pressure key-type slip ring structures.
The key contact structure provides controlled core engagement for differential winding.

Key Types	Rectangular metal key or rectangular rubber key
3-inch Ring	75.5 mm OD, 78.2 mm expansion point
6-inch Ring	151 mm OD, 155.5 mm expansion point
Core Materials	Rubber and aluminum cores
Widths	3-inch: 10–50 mm; 6-inch: 25–50 mm

Where key material and friction lining affect the choice

Positive core engagement

Rectangular metal or rubber keys bite into the core rather than relying on friction alone, for cores that tend to slip.

Two friction materials

Kraft and wool felt give noticeably different pull force curves at the same pressure — kraft roughly double the felt figure in the published data. Specify which you want.

Rubber and aluminum cores

Both 3-inch and 6-inch, with widths from 10 mm to 50 mm.

Rubber keys for softer cores

Where a metal key would mark the core, the rubber key version is the alternative.

Slip Ring

Key-ring widths, bearing bores and core contact

Key-type slip rings can be selected according to core size, key material, ring width, pressure method and required winding torque.

3-inch and side-pressure ring outside diameter is 75.5 mm, expanding to 78.2 mm.
Suitable 3-inch core inner diameter is 76.2 ± 0.2 mm for rubber or aluminum cores.
Standard widths include 10, 15, 20, 25, 30, 35, 40 and 50 mm; other widths can be designed to order.
Inner diameter options include 50 mm and 55 mm with bearing; other dimensions can be made to match the shaft core.
For a 6-inch key ring, the outside diameter is 151 mm before expansion and 155.5 mm at expansion.
Suitable 6-inch core inner diameter is 152.4 ± 0.2 mm for rubber or aluminum cores.
The 6-inch key-ring width options are 25, 30, 35, 45 and 50 mm, with other sizes reviewed as custom configurations.

Selection Notes

Specify the key material and the friction material as two separate items. Rectangular metal and rubber keys describe core contact, while kraft and wool felt describe the friction configuration used in the reference comparisons. The published curves differ substantially, so a request for a key ring of the same width still needs its material combination identified.

Replacement Slip Rings

Replacement key rings with confirmed key and friction materials

Availability

Key-type rings can be supplied as separate replacement parts without a new shaft. Rings for another manufacturer’s shaft may be made to fit when the dimensions and key-ring structure are matched. Lead time is confirmed with the quotation after the key material, friction material and bore have been checked.

What to measure / send

Identify rectangular metal keys or rectangular rubber keys, and state whether the friction material is kraft material or wool felt. Measure the ring bore: the listed options are 50 mm or 55 mm with bearing. Send core inner diameter (3-inch 76.2 mm or 6-inch 152.4 mm), ring width, center-air or side-pressure arrangement, shaft keyslot or air-hole locations, and required quantity. Photographs should show the old key ring and its position on the shaft.

What ships

A same-structure key slip ring is supplied to the agreed inner diameter, width and friction-material configuration, with the specified metal or rubber keys. The quotation records the complete configured key ring, keeping its core-contact keys and friction-material selection together.

Do not merge the key material with the friction material

This family offers rectangular metal or rubber keys for contact with the core. Separately, the force references distinguish kraft material from wool felt. A replacement description needs both: naming a rubber key does not identify the friction material, and naming wool felt does not establish the key contact. Rubber and aluminum cores are the stated applications here, with three-inch and six-inch sizes. Show the old ring and identify the core material so the intended contact arrangement remains part of the specification.

Read the kraft and felt curves as documented specimens

The page describes kraft pull force as roughly double the wool-felt figure in the published data, but the recorded specimens have different dimensions and stated structures. The kraft condition is a 30 mm wide key-type ring with a 100 mm outside diameter and 60 mm inner diameter; the felt condition names a 25 mm wide double-ball ring. Keep these test labels attached to their tables. Replacement key-ring dimensions instead follow the installed shaft, including the listed 50 mm bore or 55 mm bearing option and the actual ring width.

Technical Reference Data

Kraft or wool felt: two different pull-force curves

Key force data below retain the individual test dimensions, materials and pressure conditions; compare those conditions with the ring you need.

Refer to the category guide before comparing the key-page kraft and felt reference curves.

Key Slip Shaft Pull Force, Kraft Material, Low Pressure Range

Test condition: 3-inch key-type slip ring, 30 mm width, 100 mm outside diameter, 60 mm inner diameter, 20 x 3 groove with kraft material.

Air Pressure (kg/cm2)	0	0.2	0.4	0.6	0.8	1.0	1.2	1.4	1.6	1.8	2.0	2.2	2.4
Pull Force (kg)	0.16	0.19	0.38	0.57	0.78	1.00	1.32	1.48	1.88	2.27	2.64	2.88	3.12

Key Slip Shaft Pull Force, Kraft Material, High Pressure Range

Continuation of the 3-inch key-type slip ring kraft-material test.

Air Pressure (kg/cm2)	2.6	2.8	3.0	3.2	3.4	3.6	3.8	4.0	4.2	4.4	4.6	4.8	5.0
Pull Force (kg)	3.33	3.80	4.03	4.23	4.41	4.74	4.78	5.23	5.43	5.64	5.82	6.15	6.36

Key Slip Shaft Pull Force, Wool Felt, Low Pressure Range

Wool-felt test specimen: 3-inch double-ball slip ring with 25 mm width, 60 mm inner diameter and 20 x 3 groove.

Air Pressure (kg/cm2)	0	0.2	0.4	0.6	0.8	1.0	1.2	1.4	1.6	1.8	2.0	2.2	2.4	2.6	2.8	3.0
Pull Force (kg)	0.02	0.04	0.11	0.23	0.42	0.64	0.80	1.03	1.23	1.47	1.64	1.86	2.02	2.28	2.43	2.65

Key Slip Shaft Pull Force, Wool Felt, High Pressure Range

Continuation of the wool-felt groove test.

Air Pressure (kg/cm2)	3.2	3.4	3.6	3.8	4.0	4.2	4.4	4.6	4.8	5.0	5.2	5.4	5.6	5.8	6.0
Pull Force (kg)	2.83	3.03	3.25	3.47	3.67	3.84	4.01	4.28	4.48	4.62	4.83	5.03	5.26	5.46	5.67

Compare rectangular keys with rollers and pressure-sensitive options

Air Slip Shaft

A change from rectangular keys to pneumatic expansion needs an air-ring review, including the appropriate 8-, 12- or 16-piston and air-path configuration.

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Low Tension Slip Shaft

If a key-shaft inquiry is actually constrained by sensitive-film starting tension, compare the low-tension model’s 0.1 kg/cm² start before specifying a contact structure.

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DS Slip Shaft

For medium-tension laminate winding with pneumatic locking, review DS as a different structure and confirm that the 0.8 kg/cm² starting threshold is suitable.

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Ball Slip Shaft

For a requirement centered on very narrow slit rolls rather than rectangular engagement, compare the ball family’s single-ball and double-ball width options.

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Double Ball and Roller Slip Shaft

Where extended cylindrical contact is preferable to rectangular keys, the roller page provides rubber, aluminum and paper core configurations with distinct bearing-bore choices.

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Send key-ring dimensions and friction-material details

Have a drawing of your shaft or a photo of the old rings? Send it on WhatsApp or to sales@kendoric.com — we check fit before quoting.