FAQ

  •  Shaft Collars

     Are they weldable?

    Yes, steel shaft collars are weldable. Ruland uses 1215 lead-free steel for safety purposes when welding. The black oxide coating may need to removed exposing plain steel for a better surface to weld. This can be done using a metal brush to remove the black from a single weld spot or a tumbler to remove black completely.

     What is the Axial load capability?

    Axial load is determined by a number of different factors including shaft collar type, screw size, shaft hardness, and material. Axial load ratings for Ruland shaft collars can be found here.

     Why is face to bore perpendicularity important?

    It assures that the work surface of the shaft collar is square with the bore. This is critical in applications where the shaft collar is used as a load bearing such as controlling the stroke of a cylinder or for aligning components such as bearings or sprockets.

     Are quick clamping type available in other materials?

    No, they are only made from aluminum. Alternative materials, such as stainless steel, are not pliable enough to open/close with just a lever.components such as bearings or sprockets.

     Can Shaft Collars be used to mount to other components?

    Yes, this is a common application for shaft collars. Often customers will add tapped or through holes on the face of the shaft collar to mount directly on applications such as pulleys. Alternatively, shaft collars can be manufactured with wrench flats and OD mounting holes to secure them on applications such as sensor mounts.

     Does a two-piece have more holding power than a one-piece style?

    Yes, about 5% (BILL?). This is because it uses the full seating torque to apply clamping forces to the shaft.

     Can you make Shaft Collars with different anodize colors?

    Yes, in fact we do this in black as a standard part. Other color options are possible and this is something that comes up frequently. Recently, we made a run for the FIRST Robotics Competition in orange, purple, green, blue, black, and gold.


  •  Rigid Couplings

     What is Nypatch?

    Nypatch is a proprietary 360-degree anti-vibration coating applied to hardware on clamp type rigid and six beam couplings. It allows for even seating of the screw, repeated screw installations, and prevents galling. This pre-applied coating saves a significant amount of time during assembly as no additional screw treatment needs to be applied by customers.

     Why is precision honing important?

    Rigid couplings require perfect shaft alignment for proper use. Precision honing ensures the bores are collinear, meaning the coupling will not introduce misalignment into the system. Ruland is the only manufacturer to precision hone straight bore rigid couplings allowing them to be used in high tech servo driven systems without the fear of premature wear to bearings or other components.

     Can you make a one-piece style with keyways and different size bores?

    No, the manufacturing processes we use do not allow for a blind step keyway. Many common step bore sizes with keyways are available as standards in the two-piece style.

     I am using a Rigid Coupling in a mixer. Why does it keep breaking in the middle?

    We manufacture rigid couplings with a cross cut in the middle to allow for shaft tolerance mismatches. In applications with an unsupported shaft, such as a mixer, the oscillating shaft can overstress the cross cut leading to coupling failure.

     Do you make Rigid Couplings that fit in smaller spaces?

    Yes, double wide shaft collars are often used in applications with a limited envelope. They do not have equivalent torque capacity, however are generally well suited for these type of precision applications.

     Can Rigid Couplings be used in push-pull applications?

    Yes, they are the only style of coupling Ruland manufactures that can be used in this style of application.


  •  Beam Couplings

     Can stainless steel Beam Couplings be used in a wash down environment?

    Not in a standard configuration as the screw is alloy steel. This is a common misconception with stainless steel beam couplings. The primary reasons for using stainless steel are higher torque and torsional stiffness capabilities.

     How much axial force can a Beam Coupling withstand?

    None, they are not meant to be used in push-pull applications or with an applied axial load. The axial misalignment rating accounts for thermal expansion of the shafts during operation.

     What is the difference between four and six Beam Couplings?

    Four beam couplings are more flexible with lower bearing loads. Six beam couplings have higher torque and torsional stiffness capabilities.

     Are Beam Couplings available with keyways?

    Not as a standard item. We can make straight bore beam couplings with keyways, but not step bores. It is not recommended to use keyways with beam couplings. They will often fail before a keyway is necessary and there are other coupling styles better suited for these applications.

     Why do you only use Nypatch screws on six Beam Couplings?

    Six beam couplings can be used in light duty power transmission applications such as connecting a servo motor to lead screw. These applications are demanding and can have vibration that would cause standard screws to loosen during operation. Nypatch has the added benefit on stainless steel couplings of preventing galling.

     Can you make Beam Couplings in anodized aluminum?

    Yes, this is a common request. In small quantity they can be expensive due to minimum lot charges for anodize. Once the volume gets high enough the added cost is relatively low. They are most commonly requested with black anodize, however we can also do clear coat or hard anodize if needed.


  •  Oldham Couplings

     Why are there two ratings for parallel misalignment?

    The max parallel misalignment rating was added to show how much parallel misalignment an oldham coupling can actually accommodate. Using at this high misalignment will slightly reduce coupling life, however disks are a relatively inexpensive wear item and can be easily replaced.

     How do I specify a complete coupling?

    You must specify two hubs and one disk to make a complete coupling. Sizing information can be found here. This flexibility allows you to combine clamp or set screw hubs with inch, metric, keyed, and un-keyed bores.

     What are the main differences between PEEK, acetal, and nylon disks?

    Acetal disks are the most common type offering high torsional stiffness and zero-backlash. PEEK disks have the same benefits as acetal with the added capability of use in extreme temperature, wash down, or vacuum conditions. Nylon disks dampen impulse loads and reduce system noise.

     Are Oldham Couplings zero-backlash?

    Acetal and PEEK disks are zero-backlash. Nylon disks are still press fit, but the material is not stiff enough to guarantee consistent zero-backlash performance.

     Are Oldham Coupling hubs available in stainless steel?

    Yes, it is common to see hubs purchased in stainless steel for extreme environments. These are not a standard stock item, but can be specified on an as needed basis.


  •  Jaw Couplings

     Are Jaw Couplings zero-backlash?

    Yes, Ruland jaw couplings are zero-backlash. The proprietary curved jaw profile press fits to the spider ensuring zero-backlash operation.

     How do I specify a complete coupling?

    You must specify two hubs and one spider to make a complete coupling. Sizing information can be found here. This flexibility allows you to combine clamp or set screw hubs with inch, metric, keyed, and un-keyed bores.

     What are the main differences between red, yellow, and blue spiders?

    Red spiders are the stiffest and have the highest torque capacity. Yellow spiders combine stiffness and compliance. Blue spiders offer the highest dampening capabilities.

     What are the spiders made of?

    All are made from polyurethane.

     Are Jaw Coupling hubs available in stainless steel?

    Yes, they are not a standard stock item, but can be specified on an as needed basis.


  •  Disc Couplings

     Why is there no parallel misalignment rating for single disc couplings?

    Single disc couplings only have one set of disc springs. The bending required for parallel misalignment is too complex for the single set disc springs.

     What is the maximum voltage protection on electrically isolating disc couplings?

    You must specify two hubs and one spider to make a complete coupling. Sizing information can be found here. This flexibility allows you to combine clamp or set screw hubs with inch, metric, keyed, and un-keyed bores.

     Are disc couplings available in all stainless steel construction?

    Yes, they are not a standard stock item, but can be specified on an as needed basis.

     Can disc couplings be used in a clean room environment?

    Yes, however this needs to be specified during the design phase to ensure compliance. For example, Ruland uses stainless steel hardware with a proprietary anti-galling coating. This is not compliant with clean room conditions and the coupling would need to be supplied with uncoated screws.

     Can disc couplings be specified to have one side with and one side without keyway?

    Yes, as a special order item.


  •  Bellow Couplings

     Are bellows couplings available in all stainless steel construction?

    Yes, they are not a standard stock item, but can be specified on an as needed basis.

     How much axial force can a bellows coupling withstand?

    None, they are not meant to be used in push-pull applications or with an applied axial load. The axial misalignment rating accounts for thermal expansion of the shafts during operation.

     How do you come up with the temperature rating?

    Ruland uses an epoxy to join the bellows to the hubs. The temperature rating is equivalent to that of the epoxy.

     Are bellows couplings good for encoder applications?

    Depends on the encoder application. Generally, four beam or oldham couplings work best. They are torsionally rigid enough to maintain position and flexible enough to accommodate the large misalignment often present in encoders. If the application calls for high precision over very short increments a bellows coupling may be better suited. When using a bellows, however the system alignment needs to be almost perfect.

     Can bellows couplings be specified to have one side with and one side without keyway?

    Yes, as a special order item.


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