Explanation of Linear Guides

Key points regarding the mounting of the linear motion guide

To accurately mount linear guides use both horizontal and vertical datum surfaces at the same time (Refer to [Fig.1] on previous page). Uneven tightening of the rail clamping bolts can cause waviness especial in long rails. This section explains recommended methods when fastening rails.

How to mount rails vertically

The vertical motion accuracy of the linear motion guide is comprised of two modes (See [Fig. 1]).

1. Variation in response to tightening bolt pitch
2. Transit vibration of balls used in rolling bearing
The factor contributing to 1 is deterioration of the rail due to the tightening of the bolts clamping it ([Fig. 1]). This problem can be solved by tightening the bolts using a torque wrench, which provides constant bolt tightening torque, and then retightening them. Linear Guides are design and manufacture with precisely ground surfaces and high dimensional accuracy to minimize errors resulting from the tightening of the bolts. The ground rail mounting face achieves high straightness and surface smoothness. The rail mounting face is also generally provided with the same level of accuracy by grinding. However, because of its long, slender shape, guide rail needs to be fixed in close contact with the mounting reference plane.


Linear locks (Misumi catalog No. LLT) are very helpful for mounting rails horizontally (See [Fig. 2]).

Examples of use

1. Drill linear lock mounting holes at the same distance (pitch) as the pitch of the rail mounting holes.
2. Insert linear locks into the linear lock mounting holes, and then press a rail against the mounting face with the eccentricity of the linear lock flange.
3. Fix the linear locks by tightening the internal screws.

Tighten the linear locks and at the same time tighten the rail mounting screws. Use a dial gauge or other appropriate tool to check the vertical and horizontal waviness of the rail while fixing it.