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D.B. Roberts Company

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Fifteen "common sense" rules for achieving high quality and reducing in-house fastener costs


  1. Determine if a standard design fastener will meet the design application objective.

    If a standard screw design already exists that will meet a design application objective, its best to use it. Why? More readily available, faster delivery and in general, will cost less!

  2. Limit selection of standard types and sizes

    Its good management to stock a larger inventory of fewer parts, thereby avoiding the higher costs of small quantity reordering. You will additionally save on the reduced variety of tooling required - - - - On punching, drilling etc.

  3. Use multi- function fasteners

    Fasteners such as thread forming, thread cutting, self sealers, etc., Do more than just hold two parts together. They can be used to reduce the number of parts by having a single fastener perform the functions of two or more fasteners, thereby increasing production while at the same time cutting costs on assembly operations and minimizing rejections.

  4. Save by adding more commodity items to your companys existing ship-to-stock "breadman" turnkey inventory control system

    Leverage your existing cost savings even further by adding other commodity items, e.g. caplugs, electrical items, stampings, springs etc. The mechanics of the system are already in place, why not review an illustrated parts breakdown with the objective of targeting specific new items to add to the "breadman program". To service these new items should be a relatively easy task for your vendor's inside customer sales representative.

  5. Class 2a and 2b thread tolerance is best throughout the entire product

    The most commonly used thread tolerance is class 2a external to suit class 2b internal threads for sufficient clearance to minimize fastener driving difficulties. Allows for commercial plating buil-ups.

  6. Best to specify low carbon steel

    Also, consider the cost savings on the least expensive non-ferrous materials, where these materials are adequate for the job

  7. Adhere to the Industrial Fastener Institute standards "the industry bible" fastener standards sixth edition

    Design engineers will reap dividends by keeping their design requirements as uncomplicated as possible, obviously, where possible

  8. Communicate the fastener application in the early design stages

    Your vendor's sales staff may be able to suggest a more current design, a more efficient or less expensive fastener design. There is no cost associated with this "encyclopedia" of fastener application knowledge

  9. Specify cold-headed parts

    Cold-heading eliminates waste, increases shear strength, and offers a variety of head designs not possible with screw machine operations, all at substantial cost savings

  10. Use recommended materials on adjacent parts

    Avoid galvanic action between non-compatible metals and finishes

  11. Save by using plated fasteners where the application warrants

    Plated screws will usually forestall surface reactions and corrosion..typically at a lower cost than screws made from solid materials. Food industry and salt water environment are notable exceptions.

  12. Custom designed fasteners

    Be money ahead by using cold-headed special designs wherever possible in place of screw machine parts. Cost savings are very significant

  13. Avoid sharp corners

    Its best to alow for a radius of .005 to .010 as since more critical tolerance will add to the cost

  14. Provide most recent drawings and specifications

    A sample part, if readily available, should accompany the drawing , etc.

  15. Specify IFI industry tolerances for additional cost savings

    - Diameters
    - Lengths
    - Angles

    These tolerances are adequate in most industries; however, closer tolerances required for special aplications may be supplied by your vendor.

This technical information has been contributed by
D.B. Roberts Company

Click on Company Name for a Detailed Profile

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