Cement screws are used for fastening an object to cement or to some other type of masonry material such as brick or block.  Using cement screws is fairly simple and they work well in most applications.  As with all concrete type fasteners, not all types work in every application. Proper precaution should be taken to insure that the fastener being used provides the holding values required.

Base Material
The cement screw can be used in solid cement, brick, block or mortar joints in masonry walls.  The holding values of the cement screw in any base material is dependent on the quality of the base material as well as the quantity of the material.

Embedment
Cement screws must be embedded into the concrete a minimum distance. For the 3/16” and 1/4” diameter, the minimum embedment is 1”.  The minimum embedment depth is important because shallower embedment may not allow the cement screw to obtain enough holding power.  Minimum embedment is the minimum depth that the cement screw penetrates the base materiel.  Cement screws also have a maximum embedment that should never be exceeded.  Exceeding the maximum embedment will create installation problems, such as the cement screw getting stuck in the hole or the head of the screw shearing off.  The harder and the more abrasive the base material is then the shallower the maximum embedment may be.  The lead thread cuts or taps threads into the base material. Once worn down, the lead thread’s ability to tap or cut the threads diminishes to the point where it no longer can do the job.  Once this happens then the cement screw stops penetrating and continued torque will shear off the head or strip the threads in the base material and the cement screw will just spin in the hole.

Sizes

• Diameters- the standard cement screw comes in two diameters of 3/16” and 1/4”.

• Length – each diameter comes in different lengths ranging from 1-1/4” to 6”.  The length of the hex head cement screw is measured from underneath the head while the flat head phillps countersunk head is measured as an overall length including the head.

Head Styles
The cement screw comes in two different head styles: the hex slotted washer head and the flat head countersunk phillips head.  The hex head cement screw is used in application where the head of the screw sits on top of the fixture being fastened.  The flat head countersunk phillips is used in applications where the head of the screw is countersunk into the material being fastened.

Drivers
Each diameter and head style requires a different type as well as size of driver.  The 3/16” hex head requires a 1/4” hex driver and the flat head phillips uses a #2 phillips driver.  The 1/4” hex requires a 5/16” hex driver and the phillips flat head uses a #3 phillips driver.

Hole Size
Both diameters require a different diameter of bit to be used to drill the hole in the base material.  The 3/16” diameter cement screw needs the hole to be drilled to be 5/32” and the 1/4” needs a 3/16” hole.  The hole must be drilled using a hammer drill and the bit must meet ANSI standards for carbide tipped bits.  Hole tolerance is very important and for proper holding values the size of the hole and the cement screw being installed is critical.

How to Install

3/16” Hex Head Cement Screw

• Drill a 5/32” hole into the base material with an ANSI standard carbide tipped drill bit using a hammer drill set in the hammer and rotation mode.  Make sure that the hole is drilled to a depth of 1/4” deeper than the cement screw will penetrate the base material and that the screw meets minimum embedment depth requirements.
• Clean out the hole of all dust and debris using a vacuum, compress air and a wire brush.
• Insert the cement screw through the hole in the fixture and into the hole in the base material.
• Using a 1/4” driver, turn the screw clockwise until the head of the screw is tight against the surface of the fixture being installed.

3/16” Flat Head Cement Screw

• Drill a 5/32” hole into the base material with an ANSI standard carbide tipped drill bit using a hammer drill set in the hammer and rotation mode.  Make sure that the hole is drilled to a depth of 1/4” deeper than the cement screw will penetrate the base material and that the screw meets minimum embedment depth requirements.
• Clean out the hole of all dust and debris using a vacuum, compressed air and a wire brush.
  Insert the cement screw through the hole in the fixture and into the hole in the base material.
• Using a #2 driver, turn the screw clockwise until the head of the screw is tight and flat against the surface of the fixture being installed.

1/4” Hex Head Cement Screw

• Drill a 5/32” hole into the base material with an ANSI standard carbide tipped drill bit using a hammer drill set in the hammer and rotation mode.  Make sure that the hole is drilled to a depth of 1/4” deeper than the cement screw will penetrate the base material and that the screw meets minimum embedment depth requirements.
• Clean out the hole of all dust and debris using a vacuum, compressed air and a wire brush.
• Insert the cement screw through the hole in the fixture and into the hole in the base material.
• Using a 5/16” driver turn the screw clockwise until the head of the screw is tight against the surface of the fixture being installed.

1/4” Flat Head Cement Screw

• Drill a 3/16” hole into the base material with an ANSI standard carbide tipped drill bit using a hammer drill set in the hammer and rotation mode.  Make sure that the hole is drilled to a depth of 1/4” deeper than the cement screw will penetrate the base material and that the screw meets minimum embedment depth requirements.
• Clean out the hole of all dust and debris using a vacuum, compressed air and a wire brush.
  Insert the cement screw through the hole in the fixture and into the hole in the base material.
• Using a #3 driver, turn the screw clockwise until the head of the screw is tight and flat against the surface of the fixture being installed.