AMPG Releases a Stock Line of Grip Length Prairie Bolts™

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At the end of 2012, Accurate designed a new line of screws—Prairie Bolts™. Accurate, AMPG™ manufacturers many custom screws based on spec drawings received from specialty fastener distributors.

Prairie Bolts™ manufactured by AMPG

At the end of 2012, Accurate designed a new line of screws—Prairie Bolts™. Accurate, AMPG™ manufacturers many custom screws based on spec drawings received from specialty fastener distributors. Quite often, these special-made fasteners have specific thread lengths that end-users require based on the thickness of material being fastened. This customer demand for grip-sensitive screws motivated the development of this new line of screws that can be selected by ‘grip length’—Prairie Bolts™.

Tension & Shear Force
‘When fastening a joint, the forces on the joint are commonly a combination of both tension and shear’.

Shear Force
When a screw is installed in an application where the load is shear, the screw should not have threads in shear. In shear, the threaded portion of a screw is not as strong as the unthreaded portion of the shank. Unlike standard screws and bolts that are ordered by their overall length, Prairie Bolts™ are called out by ‘grip length’. The ‘grip length’ refers to the unthreaded shank of the screw and it is measured from underneath the flange head to the beginning of threads. Because the grip length of a Prairie Bolt™ is available to select in 1/8” increments, it makes it easier to select the right screw for the thickness of material being fastened and keeping threads out of shear. In addition, the unthreaded shank of a Prairie Bolt™ is precision machined to a tight tolerance and designed to bear against the inside hole of the material (joint) being fastened. With movement, Prairie Bolts™ provide a smooth bearing surface that protects against damaging the materials being fastened.

Tension Force
When a screw is used in an application where the load is subjected to tension, the screw head should be heavy enough to handle tension loads without yielding. Prairie Bolts™ are available with either a Flange Socket Head or Flange Hex Head. The heavy heads are designed with a flange which increases surface contact, improves holding power, and distributes loads over a larger area than standard cap screws. Flange Socket Head Cap Screws are designed to be used in tapped hole or threaded inserts. Flange Hex Head Cap Screws are use with flange and hex nuts.
All screws are made in the heart of Indiana from DFARS compliant material. Screws are offered in corrosion-resistant stainless steel, high-strength stainless steel, and lightweight aluminum: 303, 316, 17-4PH Stainless Steel & 6061T6 Aluminum.

Prairie Bolt™ - Advantages of a Grip Bolt

•Designed with grip lengths to fit the thickness of material being fastened - keeping the weaker threaded portion of the screw out of the shear plane.
•With movement, the grip length of a Prairie Bolt™ provides a smooth bearing surface that protects against damaging the materials being fastened.
•Prairie Bolts™ have Fine Threads which are less susceptible to loosening from vibration and in most applications provide higher load carrying capacities.
•Fine Threads allow for finer adjustments and require less torque.
•A flange head has a built-in washer that prevents crushing thinner and softer materials.
•Flange heads increase surface contact and provide extra holding power.
•The flanged hex heads & flanged socket heads are heavy enough to take on higher torque and tension loads.
•Prairie Bolts™ are offered in corrosion resistant materials, high-strength stainless steel and lightweight materials – ideal for a wide range of specialized fastening applications.

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Mercedes Goldberg
Accurate Manufactured Products Group Inc
317-472-9000
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