Technical Specifications for Hammer Drive (Metal Hit) Anchors
Before installing hammer drive anchors, certain technical specifications must be considered to ensure that the correct size and length anchor are used. This page will provide you with the information you need to determine which sized hammer drive anchor is required. Note that these anchors are available in 3/16" and 1/4" diameters and can be used in concrete, brick and block base material, but should not be used in overhead applications. Also, note that another name for these anchors is metal hit anchors. You may see these terms used interchangeably throughout the web.
Length:
To determine the length of Hammer Drive Anchor required, add the thickness of the material to be fastened to the minimum embedment.
Spacing:
The forces on a Hammer Drive Anchor are transferred to the base material in which it is installed. If the anchors are installed too close together, it can cause an interaction of the forces, thus reducing the holding power of the anchor. As a rule of thumb, the expansion anchor industry has established a minimum standard of ten (10) anchor diameters for spacing between anchors and five (5) anchor diameters from any unsupported edge. When vibration or sudden impact are part of the load conditions, the spacing between anchors should be increased.
Technical Information: Ultimate Load Values in 2000 PSI Concrete
| Size | Minimum Embedment | Drill Bit | Pull-Out (lbs.) | Shear (lbs.) |
| 3/16” x 7/8” | 3/4” | 3/16” | 214 | 311 |
| 1/4” x 3/4” | 5/8” | 1/4” | 307 | 330 |
| 1/4” x 1” | 3/4” | 1/4” | 405 | 450 |
| 1/4” x 1-1/4” | 3/4” | 1/4” | 405 | 450 |
| 1/4” x 1-1/2” | 3/4” | 1/4” | 405 | 450 |
| 1/4” x 2” | 3/4” | 1/4” | 405 | 450 |
| 1/4” x 2-1/2” | 3/4” | 1/4” | 405 | 450 |
| 1/4” x 3” | 3/4” | 1/4” | 405 | 450 |
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 ratio.
