Stud Anchors

Published by Robert Carlisle on Feb 23rd 2011

Purchase Wedge Anchors

Stud anchors are made from a steel rod, with one end threaded and the other end necked down with a clip that is permanently attached. Stud anchors are packaged with one nut and one washer. Stud anchors are simple to use, have excellent holding values and come in a wide variety of diameters and lengths. They are made from, or plated, using a variety of materials. Purchase and read technical information about wedge anchors.
Applications
Stud anchor is another name for a wedge anchor. They are used for fastening to concrete but are not used in other base materials, such as brick or block

Diameters
Stud anchors are manufactured in nine (9) different diameters: 1/4”, 5/16”, 3/8”, 1/2”, 5/8”, 3/4”, 7/8”, 1”, and 1-1/4”. The different diameters allow the stud anchor to be used in applications ranging from light-duty to heavy-duty fastening applications.

Lengths
Each diameter of stud anchor is available in different standard lengths and are designed to meet most application requirements:

Diameter	Length	Diameter	Length
1/4”	1-3/4”	5/8”	3-1/2”
	2-1/4”		4-1/2”
	3-1/4”		5”
5/16”	2-3/4”		6”
	3-1/2”		7”
3/8”	2-1/4”		8-1/2”
	2-3/4”		10”
	3”		12”
	3-1/2”	3/4”	4-1/4”
	3-3/4”		4-3/4”
	5”		5-1/2”
	6-1/2”		6-1/4”
1/2”	2-3/4”		7”
	3-3/4”		8-1/2”
	4-1/4”		10”
	5-1/2”		12”
	7”	7/8”	6”
	8-1/2”		8”
	10”		10”
	12”		12”
		1”	6”
			9”
			12”
		1-1/4”	9”
			12”

Diameter Selection
The diameter of stud anchor to use depends on a variety of factors. Often an engineer specifies the diameter of stud anchor, and this recommendation of a specified stud anchor should be followed. The hole diameter in the material being fastened can dictate the diameter of stud anchor required, and it needs to be slightly larger than the nominal diameter of stud anchor being used. As the weight being fastened increases, the size of the diameter of stud anchor required also increases. The weight of the object placed on the stud anchor can be in a tension load, shear load or a combination load, and will be another factor that determines the diameter of stud anchor to use.

Length Selection
The minimum length of the stud anchor used is determined by adding the thickness of the material being fastened plus the thickness of the nut and washer to the minimum embedment for the diameter of stud anchor.

Below is a chart with the minimum embedment for each diameter of stud anchor*:

Stud Anchor Diameter	Stud Anchor Minimum Embedment
1/4”	1-1/8”
5/16”	1-1/8”
3/8”	1-1/2”
1/2”	2-1/4”
5/8”	2-3/4
3/4”	3-1/4”
7/8”	3-7/8”
1”	4-1/2”
1-1/4”	5-1/2”

*The stud anchor must be embedded into the concrete after it is fully set to a minimum depth for the diameter of stud anchor being used.

Thread Lengths
The thread length of a stud anchor varies depending on the manufacturer. Many stud anchors have full threads; these threaded stud anchors have threads for most of the length of the stud. Other stud anchors have partial threads. The most important fact concerning the threads is that the anchor is always embedded into the concrete at least to the minimum embedment depth. At least six threads are below either the surface of the concrete or the item being fastened. There should be enough thread space for a nut and washer.

Material Types
Stud anchors are manufactured in a number of different types of steel as well as from plating designed for applications with different rust resistance requirements.
Zinc plated carbon steel – indoor applications where moisture is not present.
Hot-Dipped Galvanized – indoor/outdoor applications where moisture is present.
303/304 stainless steel - applications outdoors where moisture is present.
316 stainless steel – submerged in water, salt water or other caustic environments.

Stud Anchor Installation

Drill a hole in the concrete using a hammer drill in the hammer mode, with carbide tipped drill bit that meets ANSI standard B212.15 and is the same diameter as the diameter of the stud anchor being installed.
Drill the depth of the hole a minimum of 1/2” deeper than the minimum depth of embedment for the diameter of stud anchor.
Using a wire brush, compressed air or vacuum, clean the hole of all debris and dust.
Thread nut onto threaded end of stud anchor so the top of the nut is flush with the top of the stud anchor. This will protect the threads from damage during installation.
Insert stud anchor, clipped end first, into the predrilled hole in the concrete. If the stud anchor is being installed through a hole in a fixture, it is important that the hole diameter is larger than the diameter of the stud anchor being used.
With a hammer, strike the nutted end of the stud anchor until a minimum of six threads are below the surface of the concrete or the surface of the item being attached.
Using your fingers, tighten the nut.
Take a wrench and turn the nut clockwise 2 to 3 turns or until the recommended torque values for the diameter of stud anchor being used is obtained.

Recommended Torque Values

Diameter of Stud Anchor	Torque Value Ft./Lbs
1/4”	5-10
5/16”	5-10
3/8”	25-30
1/2”	50-60
5/8”	75-90
3/4”	150-175
7/8”	200-250
1”	250-300
1-1/4”	400-450

Torque Value Ft./Lbs