The 3/4” zinc plated drop-in anchor is a female concrete fastener designed for dead loads in solid concrete base material and should not be used in brick or block. The 3/4” zinc plated drop-in anchor has an internal plug that is set in the concrete using the designated setting tool.
The description of the 3/4” drop-in anchor refers to the inside diameter of the anchor or the diameter of the threaded rod or bolt that can be inserted into it. The 3/4” drop-in anchor is designed to accept a 3/4” threaded rod or bolt.
The 3/4” drop-in anchor is designed for use in solid concrete and should not be used in any other type of base material, such as brick or CMU. It is primarily used for dropping down threaded rod from concrete ceilings for applications such as a pipe run, duct work or fire sprinklers.
All 3/4” drop-in anchor come in one overall length of 3-1/8”.
The 3/4” drop-in anchor threads are national coarse threads with 10 threads per inch, commonly referred to as 3/4”- 10.
Thread length of the 3/4” drop-in anchor is about half the overall length, or about 1-1/2”
A 3/4” drop-in anchor must be installed into the concrete a minimum of 3-1/8”. The minimum embedment is equal to the anchor length. The top of the 3/4” drop-in anchor is level with the surface of the concrete when minimum embedment is achieved.
Depth of Hole
The hole in the concrete can be deeper than the minimum embedment depth for the 3/4” drop-in anchor. Deeper embedment will achieve better holding strength in most cases.
The diameter of the hole that needs to be drilled into the concrete for the 3/4” drop-in anchor is 1”.
The diameter of the bit used to drill a hole for the 3/4” drop-in anchor is 1”. The bit must be carbide tipped and meet ANSI standards to ensure proper hole tolerance.
To meet minimum holding values and to ensure that the cones of concrete do not overlap, each 3/4” drop-in anchor must be set a minimum of 10-1/2" from each other.
The distance from any unsupported edge of concrete for the 3/4” drop-in anchor is 5-1/8”, which will ensure the expansion forces will not be affected.
When a bolt will be used in conjunction with the 3/4” drop-in anchor, the length of the bolt needed is determined by considering these factors:
Flush With Concrete – when the 3/4” drop-in anchor is set flush with the surface of the concrete add the thickness of the material being fastened plus the thread length of 1-1/2” plus 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 plus space for the washer plus 1-1/2” for the thread engagement.
The 3/4” drop-in anchor is set using a setting tool; the maximum torque that can be applied to the 3/4” drop-in anchor once set is 80 ft/lbs.
Anchor Body – AISI 1008 carbon steel
Internal Plug – AISI 1018 carbon steel
Zinc Plating – ASTM B633, SC1, Type III (Fe/Zn 5)
ULTIMATE HOLDING VALUES
2000 PSI Concrete
3/4” Drop-In Anchor
*Values shown are average ultimate values and are offered only as a guide and are not guaranteed. A safety factor of 4:1 or 25% is generally accepted as a safe working load. Reference should be made to applicable codes for the specific working ration. All values are based on close tolerance holes drilled with carbide tipped drill bits. Designated holding power depends on the quality of the concrete, depth of embedment and proper hole size.
Drop-In Part Number
Setting Tool Part Number
- Using a hammer drill set in the hammer and rotation mode, drill a hole in the concrete with a 1” carbide tipped drill bit that meets ANSI standards B212.15.
- Drill the hole in the concrete to a minimum depth equal to the length of the 3/4” drop-in anchor.
- Using compressed air, vacuum and a wire brush, clean the hole of all dust and debris.
- Insert the 3/4” drop-in anchor with the open threaded end facing up.
- Take the correct 3/4” drop-in setting tool and insert the smaller diameter end into the threaded portion of the 3/4” drop-in anchor. Strike the end of the setting tool with a hammer until the lip of the setting tool meets the lip of the 3/4” drop-in anchor.
- The 3/4” drop-in anchor is now set. Threaded rod or a bolt can be inserted into it with a maximum torque of 80 ft./lbs.