Socket Head Cap Screws

January 22, 2017 by · Leave a Comment 

Socket Head Cap Screws

Socket Head Cap Screws

Standard and custom manufactured socket head cap screws.

Standard Socket Head Cap Screws

Sigma distributes quality fasteners – socket head cap screws, metric socket screws, flat head socket screws or button head socket screws. Also known as Allen head cap screws.

Custom and Modified Socket Head Cap Screws

If you specification requires a modified or custom socket head cap screw Sigma will deliver.

ASTM Material Selection Chart B7, B7M, L7, L7M, 660, 718 Inconel, 17-4 ph, MP35N

Available coated, plated and plain.

Heavy Hex Bolts

January 21, 2017 by · Leave a Comment 

Heavy Hex Bolts 

Heavy Hex Head Bolt

Heavy Hex Head Bolt

There are several ASTM bolting specifications that require a heavy hex head – larger than a standard or finished hex head. These specifications include: A193, A320 and A307B. Although A325 and A490 bolts also require a heavy hex head, they refer to Structural Bolts for dimensional specifications, since structural bolts have shorter thread lengths than standard heavy hex bolts. 

Heavy Hex Bolts are used in a varity of OEM equipment and can be manufactured in multiple ASTM grades. 

ASTM Material Selection Chart  

Check Out Heavy Hex Bolts our Bolt Catalog for Sizes and Dimensions.

12 point Flange Bolts

November 19, 2016 by · Leave a Comment 

12 point Flange Bolts or 12 point Flange Screw


These bolts feature a 12 drive surface head for high torque fit. The 12-point design provides the same bearing surface as hex or socket head cap screws of comparable size, and can fit in a confined space using  a standard 12-point socket.

Typical Usage: More than likely for use in a taped hole. 12 point head reduces the chance of tool slippage and the smaller head allows for use in confined areas on a narrow flange.

Other Common Names: Counterbore Screw,  Ferry Cap, Counterbore Screw, 12-point Flange bolt, 12-point flange screw

Catalog: 12 point flange Screws

Bolting And Ring Gasket Requirements

March 19, 2016 by · Leave a Comment 

Bolting Requirements for FlangesASME/ANSI B16.5 – 1996 – Pipe Flanges and Flanged Fittings

The ASME B16.5 – 1996 Pipe Flanges and Flange Fittings, flange bolt and gasket standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings.

The standard includes flanges with rating class designations 150, 300, 400, 600, 900, 1500, and 2500 in sizes NPS 1/2 through NPS 24, with requirements given in both metric and U.S units. The Standard is limited to flanges and flanged fittings made from cast or forged materials, and blind flanges and certain reducing flanges made from cast, forged, or plate materials. Included in this Standard are requirements and recommendations regarding flange bolting, flange gaskets, and flange joints. The standard covers the required number of bolts, diameter of the stud bolts, length of stud bolts and ring size in R, 1RF, RTJ, and RX  gaskets.

Flange Bolt Requirements