Frequently Asked Questions
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Self-Clinching
What holds the bearing in the panel?
The press force applied to the bearing during installation causes the mount material to cold-flow into the groove of the bearing retainer, permanently locking the bearing in place.
What are the requirements for the mounting hole?
The hole diameter must meet the specified size and tolerance. The edge of the hole must remain sharp — do not chamfer or deburr. If the hole is stamped and the mount material is thicker than nominal .060” [1.5mm], the bearing should be installed into the punch side of the hole where break-out is not a concern. In the design stage, ensure that the mounting hole location meets the minimum distance to the material edge. Otherwise, special tooling may be required.
Can I install the bearing with a hammer blow or similar force?
A self-clinching bearing must be installed using a squeezing action. A quick impact will not allow sufficient time for the mount material to cold-flow, and will likely cause damage to the bearing.
Do I need special equipment to install the self-clinching bearings?
Self-clinching bearings are installed using a parallel-acting press. Hydraulic, pneumatic (direct acting or toggle), and hydro-pneumatic presses are all excellent for installation. Some of our smaller bearings may even be installed with an arbor press, especially if mounted into softer materials such as aluminum. Care should be taken in all cases to ensure that the press and tooling surfaces are flat and parallel throughout the installation process.
Will a self-clinching installation affect the bearing ID?
No. Even though the resulting installation is extremely secure, the installation force is taken by the bearing retainer without affecting the ID.
Will my sheet steel fabricator be familiar with self-clinching?
The self-clinching technique is a widely used mounting technology for fasteners and as an alternative to welding.
What are the mount requirements?
The mount material must be ductile — softer than the bearing retainer (65RB maximum for steel retainers and 75RB maximum for stainless steel retainers). Also, if the installation is into sheet steel, the metal must meet the specified minimum thickness for the bearing diameter. In addition, the mounting hole must be within specified dimensions and tolerances.
Can the bearings be installed into a stainless steel mount?
Yes. Note that stainless steel retainers should be used when mounting into stainless steel.
Is there a maximum material thickness?
No. As long as the minimum thickness requirement is met, there is no maximum.
What is the push-out force required to remove the bearing?
It varies with the bearing size and panel material. Push-out forces are specified for mild steel. As a guide, a 0.250" (6mm) diameter bronze bearing would require a force of 1,100 lbs (5,000N) to remove.
Self-Aligning
What holds the bearing in the panel?
We wouldn’t recommend this unless one bearing could be moved to manually align with the other. Self-aligning bearings are usually paired so that the bearings can align with each other for optimum performance and long service life.
The alignment feature is referred to as static misalignment. What is this?
Self-aligning bearings are not designed for constant alignment motion. The self-aligning feature is designed to compensate for shaft misalignment due to manufacturing and assembly tolerances and is used during assembly to ensure that the bearings are ideally aligned with the shaft axis. Spyraflo can design a custom bearing if dynamic alignment is necessary.
How does self-aligning extend the bearing life?
From the moment a load is applied, the shaft engages the complete length of the bearing, thereby maximizing bearing efficiency and life. A misaligned shaft will not load the bearing properly. This causes additional friction, heat and wear, and can add unintentional loads to the bearing since the shaft may be in a bind.
I have an application that could potentially require greater than ± 5° of alignment.
Spyraflo has created custom designs with up to ± 30° of alignment. Contact Spyraflo customer service to see if a custom design would make sense for you.
Mounted Bearings
What material are the pillow blocks and housing flanges made of?
Standard pillow blocks and housing flanges are made from sintered aluminum. These mounts provide a lightweight, compact and corrosion-resistant assembly.
I have limited space to mount the pillow block or housing flange. Is this a problem?
Spyraflo housing flanges and pillow blocks are considerably more compact than comparable cast-iron ball bearing mounts.
Bearing Material Selection
You quote an SAE-840 bronze specification. How does this differ from SAE-841?
The Society of Automotive Engineers (SAE) established the original oil-impregnated bronze standards. ASTM specifications refer to SAE standards as well. The SAE-840 specification dictates a minimum of 25% oil volume in the structure; the SAE-841 specification is 18%. Consequently, a longer, more efficient bearing life is obtained by using an SAE-840 specification, and the benefit potential from hydrodynamic action is significantly increased.
I have a high-temperature application where the bearing is subject to temperatures in excess of 450°F. Can Spyraflo bearings accommodate this heat?
Spyraflo HT bearings can operate effectively up to 500°F (260°C). These high temperature PTFE-composite bronze bearings are available in self-clinching, press-fit and mounted configurations.
What factors should I take into account when considering a bronze bearing?
Bronze bearing lubrication is created by a hydrostatic effect whereby the load-speed combination brings the oil to the surface and lubricates the shaft. When considering bronze, keep in mind that linear motion longer than 1.5x the shaft diameter is not recommended unless the motion is very infrequent and/or the service life requirement is very low. Also note that mounting the bearing bore axis vertically is not generally recommended.
I have an application where the bearing is exposed to dust and dirt and occasional shock loads.
PTFE-composite bronze bearings operate very effectively in dusty, dirty environments and are extremely resistant to shock loads.
I have an application requiring an oscillating motion. What should I use?
Plain bearings support short-angle oscillating motion much better than rolling element bearings.
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