A winch is a stationary mechanical device which is either hand powered or machine powered and is used to wind up (pull) or wind out (let out) a cable or rope. In order to work properly, a winch must be fastened down securely to a base material. If a winch needs to be fastened to concrete, then it is essential that the correct concrete anchor is used. Large winches need to be fastened to the concrete with the use of a cast-in-place anchor or epoxy. Smaller winches can be fastened to the concrete by using mechanical type concrete fasteners such as wedge anchors. This article describes the process of fastening smaller winches to concrete using mechanical type concrete anchors.
A winch that is designed to be fastened to concrete will come with mounting holes or attachable brackets with mounting holes. The size of these holes will determine the diameter of anchors that need to be used. There are two types of concrete anchors that can be used for fastening a winch: a male type anchor or a female type anchor. The male type anchor will allow the fixture to be in place and the anchor inserted through it. Female type concrete anchors will require the hole to be spotted, the fixture removed, the anchor set in place, the fixture set back over the anchor and a bolt inserted through the fixture into the concrete anchor. It is important to follow the specifications stated by the manufacturer of the winch being fastened. This will help you select the type of anchor to be used.
Male Type Concrete Fasteners
Male type concrete fasteners allow for drilling and placement of an anchor while the fixture remains in place. It is very important to check that the anchor will fit through the mounting holes in the fixture and/or bracket. A designated diameter is larger than true hole size when using concrete fasteners. For example, a 1/2" wedge anchor requires a 9/16" hole in the fixture.
The following chart provides more detail about concrete anchor diameters and corresponding mounting hole diameters:
|Diameter of Anchor||Diameter of Mounting Hole|
Strike anchors are male type concrete anchors designed for use in solid concrete. The strike anchor utilizes a hardened drive pin to expand the body of the anchor against the concrete. Strike anchors are made from carbon steel material and are plated with yellow zinc. Anchor size is equal to hole size. A hammer is all that is needed to set the anchor. A design feature that makes the strike anchor different from the wedge anchor is that the nut is not used to set the anchor. This design allows the strike anchor to be preset at a specific depth. This provides uniform consistency of the anchor protruding above the fixture.
Wedge anchors are the most commonly used concrete anchors for this type of application. They are readily available, easy to use and have the most consistent holding values in concrete. Wedge anchors should be used in concrete only and should never be used in other base materials. The wedge anchor is a steel stud with threads on one end and a clip on the other. Wedge anchors are manufactured from carbon steel and is zinc plated or from stainless or carbon steel that is hot-dipped galvanized. The winch must be set in place and a hole drilled in the concrete and through the mounting holes. The wedge anchor is then inserted through the mounting holes and into the concrete. The nut is then turned 3-4 times to set the anchor in place.
Female Type Concrete Fasteners
Female type concrete anchors require that a bigger hole than the bolt that is placed into it. For example, if the mounting hole is 1/2" diameter and a 1/2" bolt will be used, then a 1/2" female anchor will be used. Furthermore, a 1/2" female anchor will require a 5/8" to3/4" hole to be drilled in the concrete. This will require the winch to be set in place, the concrete marked where the mounting holes are and the winch to be moved so that the holes are be drilled in the concrete. The anchor is then set in place, the winch moved back over the anchors, the mounting holes lined up with the anchor and the bolt to be inserted through the holes into the anchor. Female type anchors do not require a shear rating because the shear value is dependent on the grade of steel that the bolt is made from. When working with female concrete anchors, the length of the bolt required can be determined by adding the thickness of the material to the thickness of the nut & washer plus the length of the anchor.
Drop in anchors have the most consistent holding values of any female type concrete anchors. Drop-in anchors are available in zinc plated carbon steel and stainless steel in the following diameters: 1/4", 3/8", 1/2", 5/8" and 3/4". Each diameter comes in one length and a specific setting tool if required for each diameter. The internal threads of these anchors are coarse and extend approximately half the length of the drop in anchor. An internal plug is held in place and is designed in a cone-like shape that when pushed into the anchor with the setting tool, expands the working end of the drop in anchor against the wall of the hole in the concrete.
Below is more information about drop-in anchors:
|Diameter/Threads||Bolt Size||Hole Size||Setting Tool|
Lag Shield Anchors
Lag shield anchors are versatile and are available in two different lengths: short for use in hard base materials and long for use in suspect base material. Lag shields made from rust resistant zinc and are available in 6 different diameters: 1/4", 5/16", 3/8", 1/2", 5/8", and 3/4". The lag shield requires a lag-threaded screw to be used with the anchor. The lag shield is designed to expand as the screw is inserted into it without any use of a setting tool.
Single and Double Expansion Anchors
Both single and double expansion anchors are made from rust resistant zinc material. In single expansion anchors, a single internal nut this is pulled up through the anchor to expand the body of the anchor. The double expansion anchor has double expanders consisting of a single nut on one end and an expander sleeve on the other. As the nut is pulled up into the anchor bodies, the expander sleeve moves the opposite way and expands the anchor the entire length of the body. Both anchors are versatile since they can be used in a variety of base materials including concrete, brick, and block. Single expansion anchors work more efficiently in harder base material and the double expansion anchor derives better holding values in suspect base material. Six diameters are available including: 1/4", 5/16", 3/8", 1/2", 5/8", and 3/4".
Fastening a winch to concrete or any other base material (such as brick or block) is an application that requires the use of concrete anchors. Depending on the specifics of your application, there are a variety of fasteners that will work in this specific type of project. Both male and female type anchors can be used to fasten a winch to concrete.