Separate fixed side and support side first
BK, FK, and EK are usually fixed-side supports with bearing and locking structures for axial positioning. BF, FF, and EF are usually support-side units. The pair affects end machining dimensions.
| Comparison | BK (fixed side) | BF (support side) |
|---|---|---|
| Position | Drive end of the screw, holds axial position | Other end of the screw, supports only |
| Structure | Internal bearing plus locking | Plain support, no axial lock |
| Pairing | Used with BF | Used with BK |
| Effect on end machining | Needs journal, thread, and lock fit | Needs journal and bearing fit |
| When to choose | Drive end | Non-drive end |
Support model is not the same as screw model
Models such as BK12, BK15, and BK20 often relate to bearing bore and mounting dimensions, not directly to screw diameter. Confirm screw diameter, end journal, bearing length, and lock thread together.
Different brands may have different details
Even when the name is the same, dimensions can vary by brand. For end machining, use the real support unit, brand drawing, or customer-confirmed drawing as the reference.
- Fixed-side model such as BK12, FK15, or EK10.
- Support-side model such as BF12, FF15, or EF10.
- Screw diameter, lead, and thread length.
- End journal diameter, bearing length, and lock thread spec for both ends.
- Coupling end diameter, length, and keyway requirement.
- Installation space, overall length, and working travel.
FAQ
Do you supply BK and BF support units to traders?
Yes. Traders ordering BK or BF support units receive the same confirmation as direct buyers: support model and brand, screw diameter, end journal, bearing length, lock thread, coupling end, and export packing. This avoids mismatches when the unit is resold with a matched ball screw.
Does BK12 mean the screw diameter is 12 mm?
Not necessarily. BK12 usually relates to bearing bore and support unit mounting dimensions, not the full screw model. Confirm screw diameter, end machining, and coupling-end dimensions together.
Next step
Turn this guide into an RFQ
When the specification direction is clear, send the details below together with quantity, lead time, and packing requirements.
Include these details
- Support-unit model, end drawing, or old-part end photos.
- Bearing journal, shoulder, lock thread, keyway, and coupling-end dimensions.
- Overall length, thread length, quantity, inspection, and packing requirements.
Category
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