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ThunderDrop® - 1/2" American Made Drop-In Anchor (three one six) 316 Stainless Steel

The 1/2" American Made Drop-In Anchor (three one six) 316 Stainless Steel is designed for outdoor, wet applications. A setting tool is required to set each anchor in the concrete. Buy direct to save. All orders ship immediately with no charge for freight.

  • Bit Size 5/8"
  • Minimum embedment 2"
  • For use in solid concrete, not to be used in brick or block
  • For wet, outdoor environments
  • Meets BAA requirements
  • One length per diameter
  • Internal threads are national coarse
  • Setting tools sold separately
  • All orders over $25.00 ship freight free
Products specifications
Bit Size 5/8"
Minimum Embedment 2"
Thread Type 1/2" - 13
2000 PSI Concrete - Pull-Out (lbs.) * 3105
Type Female
Primary Concrete only
Diameter 1/2"
Length 2"
Material 316 Stainless Steel
Environment Submerged/Chemicals
Box Qty 50
Minimum Edge Distance 3-1/8"
Minimum Fixture Hole Diameter (Hole Spotted) 1/2"
Inside Anchor Diameter-Bolt Diameter 1/2"
Outside Anchor Diameter 5/8"
Internal Thread Length 13/16"
Length Measurement End to End
Bolt Length Fixture Thickness + Embedment Depth
Brand Name ThunderDrop

The anchor is made from 316 Stainless Steel. This anchor is designed for use in Concrete only, and should never be used in block or brick base material.

The anchor is designed for use in a Submerged/Chemicals environment.

Hole Diameter/Bit Diameter
The anchor requires a 5/8" hole to be drilled in the base material (Concrete only). The hole should be drilled with carbide tipped bit that meets ANSI standards and used in a hammer drill.

Designated Size
The designated size of the anchor refers to the inside diameter 1/2" of the anchor or the diameter of the threaded rod or bolt that can be inserted into it.

Diameter of Anchor
The diameter of the anchor is 1/2".

Length Anchor
The length of the anchor is 2"

Thread Type
The threads on the anchor are internal threads that measures 1/2" with 13 threads per inch, commonly referred to as 1/2"-13 .

Thread Length
The length of the threads on the anchor is 13/16" in length.

Setting Tool
Each anchor must be set in the concrete with a specific setting tool. The anchor is set using the 1/2" setting tool which is sold separately.

The anchor is packaged with 50 pieces per box and does not come with a setting tool.

Minimum Embedment
The minimum anchor embedment into the concrete is 2". Therefore, the anchor must be installed so that a minimum of 2" of the anchor is embedded into the concrete.

Depth of Hole
The hole in the concrete can be deeper than the minimum embedment depth for the anchor. Deeper embedment will usually result in better holding strength.

Fixture Hole Diameter
The hole in the fixture or material being fastened must be larger than the designated diameter of the anchor. The 1/2" diameter anchor requires the hole in the fixture to be 11/16".

Torque Value
The maximum torque that can be applied to the anchor once installed is 20 ft./lbs.

Spacing between Anchors
Each anchor must be spaced a minimum distance of 6-1/4" from each other when measured center to center.

Edge Distance
It is very important not to install the anchor any closer than 3-1/8" from an unsupported edge of the concrete.

Bolt Length
When a bolt is used in conjunction with the anchor, the length of the bolt needed is determined by considering these factors:

  • Flush With Concrete - when the anchor is set flush with the surface of the concrete, add the thickness of the material being fastened to the thread length of 13/16", and then add the space for any washers used.
  • Below Surface of Concrete - add the depth below the surface of the concrete to the thickness of the material being fastened, then add the space for the washer, and, finally, add 13/16" for the thread engagement.

Holding Values - Ultimate Load Values in 2000 PSI Concrete

Anchor Size

Minimum Embedment

Pull-Out (lbs.)

Shear (lbs.)

1/2" x 2"




Product/Company Reviews

* The figures above indicate average ultimate tension and shear failure values. A safety factor of 4:1 or 25% of ultimate value is generally accepted as a safe working load. Reference should always be made to applicable codes.

* The bits are recommended by diameter and may not necessarily be the length needed for your application. Please make sure the usable length will work for your application. *