What is Precision Ground Flat Stock?

Flat Ground Stock is a precision ground flat bar made from tool grade steel and is commonly used when the final product requires a very precise threshold. It is also referred to as gage stock, shim stock, key stock, plates, sheets, strips, squares or even flats.

It is manufactured into flat strips and precision ground to ensure that all four sides are free of defects or carburization. This ensures that products that are made from Flat Ground Stock fall within very tight tolerances (aka thickness of the material) and specifications.

What is Precision Ground Flat Stock used for?

Since Flat Ground Stock is a precision product, it is typically used to make precise tools to work metal. Flat Ground Stock can be manufactured using a variety of steel grades and can be made into a wide range of different tools. These include:

1. Machining tools such as machine ways, gauges, punches and dies
2. Cutting tools such as knives, saws, hot work tools and lathe tools
3. High temperature tools such as die casting and hot shear blades
4. Precision stainless tools such as knives and surgical equipment

How is Precision Ground Flat Stock steel made?

Flat ground stock is made by cutting machined rectangular bar to a specified length, before surface grinding the four long sides to the required tolerances. Most often the steel is annealed to increase the workability of the material, although for specialty applications the Flat Ground Stock can also be hardened.

The surface grinding is carried out to ensure that there are no defects or carburization present, so that the Flat Ground Stock can be used to machine various tools with very high precision.

The cross-rolling process also significantly enhances its toughness and increases tensile strength of flat stock in the transverse direction. But ultimately the hardness and machinability of a piece of ground flat stock depends on the steel grade.

Manufacturers produce ground flat stock in many different sizes of thicknesses, widths and lengths. For thicknesses 3/16″ and up, the ground flat stock is cold-sawn, while lighter sections of flat stock are sheared.

Regular vs oversize vs cold drawn flat stock

There are two different tolerance specifications for ground flat stock – regular and oversize – as well as cold-drawn flat stock.

Regular ground flat stock has the most tightly controlled tolerances for thickness and width.

Oversize ground flat stock has extra grind stock on the thickness and width dimensions, enabling the end-user to cut the piece, heat-treat it and/or grind it to a precise dimension.

Cold drawn ground flat stock differs in that it is not precision ground but more akin to drill rod. However, unlike an ordinary drill rod, the shape is rectangular. When it comes to thickness and width tolerances, these are similar to the tolerance of regular ground flat stock.

How does Precision Ground Flat Stock steel differ from Flat Bar?

Flat Bar has a more industrial application that doesn’t require much precision. Typical uses include frame construction, building supports, reinforcement or even for industrial artwork. Flat Bar is both easily workable and can be cut to size on site, while retaining its strength and durability. However, it isn’t surface ground to give very fine tolerances.

Conversely, Flat Ground Stock is manufactured to within very tight tolerances that are not required for the industrial applications typical of Flat Bar. As such, Flat Ground Stock should be stored and handled carefully to ensure the final finish is not damaged.