purchasing and using steel for projects

Metric Fastener Usage Guidelines

Metric fasteners use a millimeter measurement for the diameter, length, and pitch of a fastener. If you are accustomed to using an inch measurement when using fasteners, use a conversion chart to guide you in selecting the right metric hardware for an application. Additionally, use some guidelines to preserve the condition of the fasteners that you utilize.

Refer To A Conversion Chart

A conversion chart can be printed online or purchased from a hardware shop. This type of chart may feature pictures of fasteners, including a side view and a top view. Fasteners come in threaded and unthreaded varieties. On a chart, you will see examples of both metric and standard fasteners. The chart can be used as a quick reference guide, when purchasing new metric hardware or when attempting to select the proper metric fastener from your fastener supply.

Prevent Oxidation

Hot-dip galvanized fasteners are manufactured and dipped in a zinc coating. Once this coating hardens, a metric fastener is protected from oxidation. Oxidation can cause a fastener to weaken and can discolor the head or shaft of a fastener. Due to the addition of the galvanized coating, the threaded or unthreaded shaft of a hardware piece will be slightly thicker than a metric fastener that doesn't contain a galvanized coating.

To prevent friction when assembling screws, bolts, and nut assemblies, refrain from mixing galvanized hardware with non-galvanized hardware. Metric hardware pieces that will be attached together should always be constructed of similar material. This will ensure that hardware pieces fit snugly, upon tightening them. 

Use A Lubricant For Stainless Steel

Stainless steel metric fasteners contain a translucent coating that is invisible to the eye. This type of lubricant provides protection from oxidation. Because the coating is thin, hardware pieces may rub together when they are attached. As a result, the thin protective coating can wear down and stainless steel will become susceptible to oxidation. The oxidation process is a chemical reaction that occurs between metal molecules and oxygen molecules.

To protect the outer coating and preserve the condition of metric fasteners, purchase a lubricant. Oil or a protective salve should be applied to hardware pieces that aren't heavily coated with a protectant. The product can be sprayed or brushed onto hardware, prior to using the fasteners to attach building materials. Although a lubricant will be somewhat greasy, it will not affect the condition of the building materials that are being secured together.