Double End Studs

January 11, 2017 by · Leave a Comment 

 

Double End Studs – Double ended studs

Double End Studs Bolts

Double End Studs

At Sigma Fasteners we provide mission critical bolting products for the nations leading manufacturers of pressure control equipment for controlling pressures during drilling and oil production.

Double-end studs used by many of these manufacturers have equal-length threads on each end to accommodate a nut and are threaded to a Class 2A fit. Length of stud is measured overall. Both ends have chamfered points, but round points may be furnished on either or both ends at the manufacturer’s option, This style is furnished in the same four types listed for tap-end studs. Double-end studs are used for flange bolting or other applications where torching from both ends is necessary or desirable.

Most steel grades not heat treated or quenched and tempered can be furnished on special order for production quantities. Only the Type 2 continuous thread studs made to specification ASTM A193 grade B7 are stocked in a full range of sizes.

ASTM Material Selection Chart B7, B7M, L7, L7M, 660, 718 Inconel, MP35N

Flange Bolts

November 13, 2016 by · Leave a Comment 

Custom Flange Screw

Custom Flange bolt

These hexagonal headed or double hex headed bolts are recognizable by the oversized washer face on the bolt head which forms a distinct ridge. This built-in washer under the head of the bolt distributes the fastening force over a large area. A flange bolt is designed to provide the clamping power over a washer and bolt combination. Available in both Hex Head and 12 point double hex head selections. The 12 Point Flange Bolts and Screws are an alternative head design with more torqueing force than standard hex cap screws. The twelve point design permits greater torque to be applied to the screw.

There are many critical design features of a flange bolt or flange screw including the fillet on the underside of the head. The fillet is the transitional curve from the bearing to the body of the fastener. Bearing surface on the flange screw or flange bolt is also key to its design integrating the extra grip strength. In addition, wrenching height on a flange bolt or flange screw is critical dimension that is measured from the top of the head to the top of the flange.

Sizes are available from ½ – 2 inch in a variety of ASTM fastener grade alloys and available to custom manufacture per print specifications.
These can be coated or plated with a variety of finishes. Xylan, PTFE, SermaGard and zinc and bake.

12 Point Flange Screws
12 point Flange Bolts

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Stud Bolts

May 25, 2016 by · Leave a Comment 

Stud bolts for Pressure-Temperature Piping

Stud Bolts are used in High Pressure & Temperature flanged fittings

REFERENCE
Stud bolts for high pressure & high temperature applications conform to the requirements of ANSI/ASME B16.5, Steel Pipe Flanges and Flanged Fittings.

LENGTH-FIRST TO FIRST
The length of stud bolt, measured parallel to the axis, is the distance from first thread to first thread. First thread is defined as the intersection of the major diameter of the thread with the base of the point. Please see the drawing above-this is confusing to most users!! Stud bolts are normally available from stock in 1/4 inch length increments. Length tolerances, all stud bolt sizes, shall be as tabulated below:

Length, in. Length Tolerance, in.
to 12                           +/-0.062

over 12 to 18          +/-0.125

over 18                      +/-0.250

POINTS
Points shall be flat and chamfered, or sheared at option of the manufacturer. When points are flat and chamfered, the diameter of the flat shall not exceed the minor diameter of the thread, and shall be not less than one or more than two complete threads as measured from the extreme end parallel to the axis.

THREADS
Threads shall be Unified inch coarse thread series (UNC), Class 2A, for all stud bolt sizes 1 in. and smaller, and Unified inch 8 thread series (8 UN), Class 2A, for all stud bolts larger than 1 in., in accordance with ANSI/ASME B1.1. Acceptability of screw threads shall be determined based on ANSI/ASME B1.3.

MATERIAL
Chemical and mechanical requirements shall be specified by the purchaser and shall be in accordance with applicable ASME, ASTM, and ANSI codes and specifications current at the time of ordering.

ASTM Material Selection Chart – Stud bolas are available in ASTM A193 Grade B7, B7M, L7, L7M. As well as 660, 718 Inconel, Mp35N and other high nickel alloys and stainless steels.

DESIGNATION
It is recommended that stud bolts be designated in the following sequence: product name, nominal size, threads per inch, length, material, and protective finish, if required.

Example: ANSI/ASME B16.5 stud bolt,
5/8-11 x 3-1/2, ASTM A193, Grade B7, Zinc & Clear Chromate Plated