1. Why Does Sticking Happen? (Common, and Often Not a Defect)

A linear guide is a high-precision component, so small changes during shipping or mounting can be felt immediately. Sticking or “tight spots” often come from the following situations:

• Shipping influence: After 2–4 weeks of sea or air transport, the anti-rust oil or grease applied at the factory can become more viscous, so hand-feel becomes “draggy” when the carriage is pushed.
• Mounting deviation: If the rail is not mounted on a flat reference surface, the block will be loaded unevenly and will feel tight at certain sections.
• Small-size rail sensitivity: Light-duty micro rails such as MGN12 have lighter preload and smaller balls, so they are more sensitive to installation error than heavy-duty rails like HGR20. A small deviation can be felt very clearly by hand.

In other words, “sticking” ≠ “quality failure” in most cases. It simply means the rail needs to be cleaned, re-lubricated, and mounted in the right sequence.

2. Fix It in 3 Practical Steps (No Replacement Needed First)

Step 1: Clean and Re-Lubricate

Wipe off the old or sticky grease on the rail and block with a clean cloth. Then apply a suitable industrial lithium-based grease (or the type recommended in the product page). Move the carriage back and forth several times so the grease can enter the raceways. In many cases, the “rough” or “sticky” feeling is reduced just by doing this.

No matching grease on hand? Do a temporary clean + light oiling first, confirm smooth motion, and then apply the formal grease later.

Step 2: Mount by “Spot-Fix → Test → Full Tightening”

A lot of stiffness actually comes from tightening all screws at once. Use this sequence instead:

1. Check flatness: Use a level or feeler gauge to confirm the mounting surface is within a reasonable flatness (we recommend ≤ 0.1 mm/m for better results).
2. Fix only 2 screws first: Place the rail, install two screws far apart, but do not fully tighten. Push the block from end to end. If it is smooth, the rail body is OK.
3. Tighten gradually: Tighten other screws one by one. After every 2–3 screws, push the block again. If a certain screw causes a tight spot, slightly loosen or re-adjust that position.
4. For dual rails: Always install the reference rail first, and then install the second rail. This avoids the carriage getting squeezed in the middle.

This step-by-step tightening makes it easy to locate which position causes the blockage, and you can fix it immediately on site.

Step 3: Still Sticking? Send Installation Evidence

If the rail is still tight after cleaning and proper mounting, we will help diagnose it. To speed up cross-border support, please send:

• Close-up photo of the sticking position
• Photo of the level or flatness reading on the mounting surface
• Overall installation photo showing rail, screws, and the machine surface
• Your order or invoice number

With these, our technician can respond within 1 business day with a clear solution — adjustment guidance, block replacement, or rail replacement depending on the finding.

3. Cross-Border Procurement Protection

We know international buyers care about delivery risk and after-sales time. That’s why we build protection into every stage:

• Prevention before shipping: Rails longer than 800 mm are reinforced and stress-relieved before dispatch to reduce the risk of deformation in transit.
• After-sales guarantee: If the problem is confirmed to be product-related (for example, abnormal raceway in the block), we will send a replacement block or even a full rail, and the cross-border shipping cost will be covered as agreed.
• Technical support: We provide installation videos in English and Chinese (YouTube link can be placed in the product page), and you can book online guidance via WhatsApp for tricky assemblies.

Pro Tip for Integrators and OEM Buyers

If you are installing multiple rails on automation equipment, request 1 sample rail for installation testing first. We support “sample + same batch” delivery for mass orders so the installation feel stays consistent across machines and you avoid batch-to-batch deviation.