Measured in Millimeters, Marked with a Crayon and Cut with an Ax

How to Present Useful Specifications and Product Requirements to Candidate Vendors

This old engineer’s adage continues to ring true at EastBridge Engineering ( when we review clients’ product requirements. Before we can research, qualify and appoint candidate vendors in Greater China, it’s critical to understand our client’s technical requirements, so we review their designs, drawings and specifications.

What we find are projects that fall into two camps. The first are products that are poorly described and barely have any specifications or tolerances. If we provide this type of documentation to a vendor, there’s no predicting what will arrive in the box. [As my wife the kindergarten teacher tells here students “you get what you get and you don’t get upset.” More on this topic in a future posting.]

The second are products that are so closely specified and toleranced, there’s absolutely no way that any vendor can make the product (at a reasonable price). In an effort to be helpful, some engineers and designers call out not only the technical requirements but also the manufacturers’ part number of every nut, bolt, screw and washer. If the parts in question aren’t critical to the operation of the finished device, this level of specification adds tremendous complexity for the vendor and numerous delays and cost.

Another example are tolerances that can’t be measured or held for certain materials or parts. Recently we had a client request a three place decimal tolerance on a laminated neoprene rubber cozy. The dimensional stability of this material combined with standard manufacturing techniques simply won’t support this level of tolerance.

We recommend that engineers, industrial designers and procurement professionals define their products to the “eighty-five percent” level. This will allow the factories bidding on your project the latitude to source non-critical parts economically and the ability to use standard manufacturing processes.


Jack Daniels

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