Founded in 1998,Specializing in Expansion Anchor Bolts and Cable Installation Parts.
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Double Expansion Bolts

To expand the anchor body by tightening machine bolt to anchor and fix the fixtures in the masonry, brick or soft-loose drywall substrate, made of the zamac alloy materials with the full dimension from 1/4" to 3/4" Unc internal threads.
  • American Inch Standard
  • OEM
  • 7318159001

    It is made of a die-casting zinc alloy material with the characteristics of rust prevention, corrosion resistance and environmental protection, and the product is durable. It has two tapered conical expansion nuts, one threaded and the other unthreaded. One or two spring strips wind the two parts together with two zinc alloy shields and allow the anchor to expand after installation.

     The length of bolts used for the installation of all anchors is equal to the thickness of the material to be fastened plus the embedded depth of the anchor. Zinc alloy double expansion bolts anchors are suitable for installation projects with soft base materials or insufficient strength. The double expansion anchor has a threaded nut at one end. During installation, clamp the other end or the other end with unthreaded nut, and then insert the threaded nut end into the hole. Place the hole with the end of the nut facing upward to ensure adequate expansion. Hit gently with a hammer until the anchor is flush with the surface of the substrate. Take the clamped fixture and align the holes on the fixture with the double holes on the substrate. Turn the bolt clockwise until the anchor is fully seated. Do not over torque the bolt as this may cause the double expansion anchor to rotate in the hole and lose its fixing strength.

    These swells are fully contacted from both sides and held safely. To install, tap in a hole with a hammer and position the fixture. Then insert the screw or screw and tighten. To achieve maximum expansion, the anchor should protrude slightly from the surface before screwing in the screw. The tensile strength and shear strength are 25-30% of the limit value. A unique feature of the double expansion anchors is that they can be easily removed from the mounting holes and reused. To remove one, just take out the machine screw and it will return to its original shape. It can then be removed from the hole.

To install the concrete double expansion anchors, perform the following steps:

1. Drill a hole with the same diameter as the anchor body on the base course. The drilling depth needs to be slightly longer than the depth of the anchor body.

2. After removing the debris and impurities from the hole, insert the double expansion anchor into the hole with the threaded end near the bottom of the hole.

3. Drill a hole in the installation object to be anchored, align the hole, and screw the matching machine screw into the internal thread in the anchor body. At first, the screw in bolts can be rotated by hand

3. Then use a screwdriver to tighten the machine screw until it is close to the surface of the object connected with the installation.

double expansion bolts installing

 Anchor Size Inch Min. Drill Dia. Inch Hole Depth Inch
1/4 1/2 1-1/4
5/16 5/8 1-1/2
3/8 3/4 1-3/4
1/2 7/8 2-1/4
5/8 1 2-1/2
3/4 1-1/4 3-1/2

**The zamac single expansion anchors are  available.

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