BK BF Paired End Supports

Product Details

The BK unit is assembled around the stepped end of the screw nearest the coupling. Its bearing set, retaining hardware and shaft shoulder work together to determine where the screw sits along its axis. Once this end is secured, the screw has a defined reference position relative to the machine base.

 

At the far end, the BF housing receives the smaller support journal. Its bearing controls radial movement but does not perform the same locating task as the BK assembly. This difference is intentional: the screw should not be rigidly trapped between two independently positioned end units.

 

The supplied product set shown on the page includes two pedestal-style housings together with separate retaining components. The exact shaft machining must correspond to the bearing bores and fastening parts inside the selected supports.

 

Product Description

Installation should begin from the BK side. Seat the screw shoulder against the fixed-end bearing arrangement, install the retaining components and confirm that the shaft is properly located before connecting the BF end.

 

The BF housing can then be positioned around the opposite journal. Its mounting bolts should remain loose until the screw has been rotated through several turns. This allows the housing to settle on the actual shaft center rather than being forced into a position determined only by the machine-base holes.

 

After both housings are secured, check the screw at more than one rotational position. A tight point that repeats once per revolution may indicate a shaft or journal issue. Continuous resistance after the BF bolts are tightened is more likely to indicate that the two mounting faces are not sharing the same centerline.

 

Product Information

Item	Specification
Product Combination	BK fixed-side unit with BF supported-side unit
BK Position	Drive and coupling end
BK Function	Establishes the axial shaft datum
BF Position	Opposite screw end
BF Function	Supports the end journal radially
Housing Style	Pedestal mounting
Visible Accessories	Locknut and retaining ring
Matching Requirement	Support size must correspond to shaft-end machining
Installation Check	Free rotation before and after final tightening

 

 

FAQ

Which support should be assembled first?

The BK fixed-side unit should be completed first because it determines the axial position of the screw. The BF housing is aligned afterward.

Why should the BF bolts remain loose during initial assembly?

Temporary looseness allows the BF housing to follow the actual shaft center. Tightening it too early can pull the journal sideways.

Can the BK and BF housings exchange positions?

No. Their internal bearing arrangements and their duties within the screw assembly are different.

What can cause the screw to tighten after final assembly?

Possible causes include offset mounting faces, an incorrectly seated shaft shoulder, unsuitable journal dimensions or a BF housing tightened away from the screw centerline.

Is the support number enough for ordering?

The complete BK and BF designations should be supplied together with the shaft-end drawing. Journal diameters, shoulder positions and retaining threads must correspond to the selected units.

 

About Us

Lishui Guangyuan Industry & Trade Co Ltd supplies ball screw support units and related mounting components for replacement work and new machine assemblies.

We build to customer drawings under OEM/ODM, and accept orders as small as a single piece for standard sizes.

 

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