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Ball Spline Precautions on Use


  1. Please use at least two people to move any product weighing 20 kg or more, or use a dolly or another conveyance. Doing so may cause injury or damage.
  2. Do not disassemble the parts. This will result in loss of functionality.
  3. Tilting a spline nut or spline shaft may cause them to fall by their own weight.
  4. Take care not to drop or strike the Ball Spline. Doing so may cause injury or damage. Giving an impact to it could also cause damage to its function even if the product looks intact.
  5. When assembling, do not remove the spline nut from the spline shaft.
  6. When handling the product, wear protective gloves, safety shoes, etc., as necessary to ensure safety.

Precautions on Use

  1. Prevent foreign material, such as cutting chips or coolant, from entering the product. Failure to do so may cause damage.
  2. If the product is used in an environment where cutting chips, coolant, corrosive solvents, water, etc., may enter the product, use bellows, covers, etc., to prevent them from entering the product.
  3. Do not use the product at temperature of 80℃ or higher. Except for the heat-resistant models, exposure to higher temperatures may cause the resin/rubber parts to deform/be damaged.
  4. If foreign material such as cutting chips adheres to the product, replenish the lubricant after cleaning the product.
  5. Micro-strokes tend to obstruct oil film to form on the raceway in contact with the rolling element, and may lead to fretting corrosion. Take consideration using grease offering excellent fretting prevention. It is also recommended that a stroke movement corresponding to the length of the spline nut be made on a regular basis to make sure oil film is formed between the raceway and rolling element.
  6. Do not use undue force when fitting parts (pin, key, etc.) to the product. This may generate permanent deformation on the raceway, leading to loss of functionality.
  7. Skewing or misalignment of the spline shaft support and spline nut can shorten service life substantially. Inspect the components carefully and make sure they are mounted correctly.
  8. The spline nut must contain all its internal rolling elements (balls) when mounted on the spline shaft. Using a spline nut with any balls removed may result in premature damage.
  9. Please contact THK if any balls fall out of the spline nut; do not use the spline nut if any balls are missing.
  10. To mount the spline nut on the spline shaft, first locate the alignment indicators on both components, then insert the shaft through the opening in the spline nut, without forcing it, and adjust the position until the indicators are aligned. Forcing the shaft could cause balls to fall out. When mounting a spline nut equipped with a seal or preload, first lubricate the outer surface of the spline shaft.
  11. Manipulate the spline nut gently, using a jig, when inserting it into the housing, taking care not to strike the side plate, end cap, or seal.
  12. If an attached component is insufficiently rigid or mounted incorrectly, the bearing load will be concentrated at one location and performance will decline significantly. Make sure the housing and base are sufficiently rigid, the anchoring bolts are strong enough, and the component is mounted correctly.
  13. If desiring to have a flanged-type Ball Spline additionally machined, such as having a dowel pin hole, contact THK.


  1. Thoroughly wipe off anti-rust oil and feed lubricant before using the product.
  2. Do not combine different lubricants. Mixing lubricants can cause adverse interaction between disparate additives or other ingredients.
  3. If the product will be exposed to constant vibration or high or low temperatures, or used in a clean room, vacuum, or other special environment, apply a lubricant suitable for both the specifications and the environment.
  4. To lubricate a product that has no grease nipple or oil hole, apply lubricant directly to the raceway surface and execute a few preliminary strokes to ensure that the interior is fully lubricated.
  5. Bear in mind that the Ball Spline’s slide resistance is affected by changes in the consistency of the lubricant, which varies according to the temperature.
  6. The Ball Spline may encounter increased slide resistance following lubrication, due to the lubricant’s agitation resistance. Make sure to put the unit through some preliminary motions to ensure that it is fully lubricated before starting up the machine.
  7. Excess lubricant may spatter immediately after lubrication. If necessary, wipe off any spattered grease.
  8. Because lubricant performance declines over time, lubrication must be monitored regularly and fresh lubricant applied when needed, depending on how frequently the machine is operated.
  9. The appropriate lubrication schedule will depend on usage conditions and the surrounding environment. In general, the unit should be lubricated after every 100 kilometers of operation (every 3 to 6 months). The actual lubrication schedule and amount of lubricant used should be determined by the condition of the machinery.
  10. With oil lubrication, the lubricant may not always be thoroughly disseminated inside the Ball Spline, depending on its mounting position. If the preferred lubrication method is oil lubrication, please consult THK in advance.


When storing the Ball Spline, enclose it in a package designated by THK and store it in a room in a horizontal orientation while avoiding high temperature, low temperature and high humidity.After the product has been in storage for an extended period of time, lubricant inside may have deteriorated, so add new lubricant before use.


Dispose of the product properly as industrial waste.