SIT SERVOMATE GSMM Hubs (Pilot Bore)
GSMM clamping hubs with a pilot bore are parts designed for SIT SERVOMATE disc couplings. They are sometimes simply called standard GSM series hubs, or labeled as GSM M.
SIT SERVOMATE are all-metal, torsionally rigid disc couplings with backlash-free torque transmission, designed specifically for servomotor drives where maximum positioning accuracy is required. They transmit torque through a highly durable disc pack fitted between the hubs. They can operate in two configurations – in a single version with one disc pack, without the ability to compensate for radial misalignment, or in a double version with two disc packs and a spacer ring, which compensates for radial misalignment at the cost of a longer design, higher moment of inertia and half the torsional stiffness. GSMM hubs are made of aluminum alloy with a pilot bore and a hole for a radial clamping screw. They are therefore supplied as semi-finished parts, and the bore must be machined to size before mounting on the shaft.
Products are sorted by name in ascending order.
SERVOMATE 15 GSM (GSM015M) - Hub (Pilot-Bored, d = 5.5 mm, Al Alloy)
Shaft Coupling
At Supplier
Within 3 Weeks Usual time this product is ready for shipping. Actual availability may vary due to unforeseen circumstances in exceptional cases.
21.34€ excl. VAT
25.83€ incl. VAT
SERVOMATE 20 GSM (GSM020M) - Hub (Pilot-Bored, d = 7.5 mm, Al Alloy)
Shaft Coupling
At Supplier
Within 3 Weeks Usual time this product is ready for shipping. Actual availability may vary due to unforeseen circumstances in exceptional cases.
23.42€ excl. VAT
28.34€ incl. VAT
SERVOMATE 25 GSM (GSM025M) - Hub (Pilot-Bored, d = 9.5 mm, Al Alloy)
Shaft Coupling
At Supplier
Within 3 Weeks Usual time this product is ready for shipping. Actual availability may vary due to unforeseen circumstances in exceptional cases.
26.79€ excl. VAT
32.42€ incl. VAT
Products are sorted by name in ascending order.
Shaft Coupling Construction
- GSMM hubs with a pilot bore and a hole for a radial clamping screw
- GSMPL disc packs
- GSMC spacer
Typical Applications
SIT SERVOMATE disc couplings are designed specifically for drives controlled by servo motors, where in addition to torque transmission, maximum positioning accuracy and zero backlash are required.
They are used, for example, on the axes of CNC metalworking and woodworking machines, in robotics and manipulators, on packaging and printing machines, in instrumentation, measurement and automation technology, and on laser and cutting machines, as well as in other precision automated drives with closed-loop position control. They are also used in the food, chemical, paper, metalworking, and automotive industries.
Coupling Code Description
Example:
SERVOMATE 20 GSM (GSM020M) - Hub (Pilot-Bored, d = 7.5 mm, Al Alloy)
| Code Part | Description |
|---|---|
| SERVOMATE |
SIT coupling type |
| 20 |
Coupling size designation |
| GSM |
Coupling type |
| GSM020M |
Alternative part designation |
| Hub |
Part name |
| d = 7.5 mm |
Pilot bore diameter in mm |
| Pilot-Bored |
Hub design |
| Al Alloy |
Hub material |
Documents for Download
Related Products
SIT SERVOMATE GSMPL Disc Packs
SIT SERVOMATE GSMC Spacers (Double Shaft)
SIT SERVOPLUS Bellows Couplings
All-metal, torsionally rigid, zero-backlash bellows couplings with clamping hubs and a stainless steel bellows element
We also provide design and calculation of transmission components, including shaft couplings. In the case of your interest in this service, use the detailed Drive or Coupling Calculation Form.
Shaft Coupling Manufacturer Profile
SIT S.p.A. is a company focused on mechanical power transmission (SIT stands for Società Italiana Trasmissioni, meaning Italian Power Transmission Company). Under the SIT brand, it develops, engineers, manufactures, and distributes high-quality solutions and components for industrial applications across a wide range of sectors – from automotive and precision engineering to the food and textile industries, as well as chemical plants and logistics centers.
Together with Elatech S.r.l. and other companies, SIT S.p.A. is part of the Scaglia Group. The Group operates in Europe, North America, and Asia, and comprises 7 manufacturing facilities and 6 subsidiaries with more than 1,000 employees. As part of the Group, the individual companies benefit from shared technologies and innovations, providing financial stability and sustainable growth.
We are an authorized distributor of shaft couplings, bushes, sprockets, and pulleys from SIT S.p.A., as well as polyurethane timing belts and conveyor belts from Elatech S.r.l.