Complete Guide to Installing and Removing Expansion Bolts

Expansion bolts are widely used basic fasteners that achieve stable fixation through friction grip generated by wedge angles. Common materials include carbon steel and stainless steel, which are durable but may still rust over time. Below is a detailed explanation of the installation steps for expansion bolts, along with efficient methods for removing rusted ones—practical and easy to follow.

I. Installation Steps for Stainless Steel Expansion Bolts

1. Drill a hole matching the expansion sleeve's outer diameter using an electric drill. For softer wall tiles, use a slightly smaller drill bit. After drilling, insert the expansion bolt assembly into the hole, leaving the nut unfastened to prevent the bolt from falling into the deep hole and becoming difficult to retrieve.

2. After securing the expansion bolt position, unscrew the nut. Align the mounting holes of the object to be fixed with the bolt, then install the spring washer and flat washer in sequence. Finally, tighten the nut. Ensure the expansion sleeve is fully embedded into the wall—the deeper the sleeve is embedded, the more secure the fixation.

II. Removal Method for Rusted Stainless Steel Expansion Bolts

1. Vibration

Never forcefully twist rusted screws. First, gently tap the wrench handle with a hammer. The vibration loosens rust buildup between the screw and nut, preventing breakage or jamming from direct force. Attempt to turn after vibration.

2. Striking

Directly strike the rusted nut with a hammer to loosen the rust layer and its grip. If ineffective, strike the nut in a circular pattern around its circumference. Once sufficiently loosened, the nut should come off easily.

3. Heating

For severely rusted screws, thoroughly heat the screw with an oxyacetylene torch flame. Utilizing thermal expansion and contraction, immediately drip lubricating oil onto the red-hot screw. This causes rapid contraction, widening the gap with the nut. Once the oil penetrates, the nut can be unscrewed smoothly.

4. Welding

If the screw head is broken off, avoid drilling holes (which may damage the threaded hole). Instead, weld a long iron rod of matching diameter onto the broken thread. Rotate the iron rod to pull out the broken thread.

5. Impact Method

For screws with corroded or deformed heads that cannot be operated with a wrench, use a hammer and flat punch to vertically strike the head, creating a V-shaped groove. Adjust the punch angle to align with the desired extraction direction and strike. Once loosened, use pliers to twist the screw out.