Steel Manufacturing Blog: Keeping it Steel

5/8” Diameter Askew Head Bolt Will Save the Day

Posted on Sun, Jul 07, 2024 @ 09:14 PM

Wedge-Insert-Rennovation-350-x-328The renovation project shown in Fig. 1 is currently taking place in the metro New York City area. The structure is a four-story garden apartment building originally constructed in the late 1950’s.

Fig. 1
A late 1950’s 4 story Garden Apartment
showing the concrete structure in very
good condition. In each level Wedge
Inserts are embedded.


Noteworthy in the project are the Wedge Inserts. Fig. 2. These embeds utilize 5/8” diameter Askew Head Bolts. This was the common practice at the time. In later years the wedge insert and askew head bolt were upgraded to 3/4” diameter. The two sizes were available for many years but eventually the 3/4” diameter was adopted as the standard. 5/8” Wedge Inserts were no longer manufactured and have since disappeared from the market.Wedge-Insert-Rennovation-300-x-184

Fig. 2
Close up shows Embedded Wedge Inserts employing 5/8” diameter Askew Head Bolts.

The Relieving Angles will be replaced and the desire is to re-use the Wedge Inserts. The alternative is drilling new holes in the concrete for each of the approximately 2,500 existing Wedge Inserts. While they are approximately 65 years old, once a structure is complete and the exterior brick wall is in place the Wedge Insert is mostly shielded from the effects of the elements and therefore can have an extended service life. Nonetheless, it cannot be assumed the inserts were originally hot dip galvanized, or if they were, the coating is still serviceable. Visual inspection and sample pull out tests are required.

To accommodate situations like this, The Steel Supply Company continues to manufacture and stock 5/8” diameter Askew Head Bolts. They are available Hot Dip Galvanized in 3”, 4” and 6” lengths. Stainless steel can be made to order. Assuming the existing Wedge Inserts pass inspection, this method can save significant man hours and cost on the project.