1. #1
    Hi Guys,

    I wonder if anyone can explain to me what a C of C actually is?

    The reason I ask is because a customer has recently asked us to provide one with a part we have machined. We supplied the C of C for material but they want one for the actual machined product. There is a finishing process the part which we are not carrying out but is on the drawing.

    Is it normal to ask for a C of C for a machined part? We are not ISO registered.

  2. #2
    There is a template on a UK .gov site -
    If that's any help?

    - Nick

  3. #3
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 8-9 years. Has a total post count of 1,314. Received thanks 126 times, giving thanks to others 3 times.
    My understanding is you only need a Certificate of Conformity for a finished product, not individual parts, as it's certifying that the product meets the required legal requirements.

    Probably be better asking over on Practical Machinist, as there'll be users over there who are far more clued up on it.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  4. #4
    Quote Originally Posted by newtoid1986 View Post
    Hi Guys,

    Is it normal to ask for a C of C for a machined part? We are not ISO registered.

    Of course it is normal. It states that you are abiding by the customers drawing and providing them with what they paid for and are liable for any discrepancy. Iso or not makes no difference. You basically put in writing that the parts you made are good. Ideally you will have inspected a number of parts from the batch and ensured they are to tolerance according to the drawing. How many of the batch you inspected should have been discussed before you took the order.
    Stocking more goodies than just Smoothsteppers

  5. As George says a C of C is just a declaration by you that what you're supplying conforms to what they ordered be it a part or a complete assembly.

    Build log...here

  6. #6
    It's a thing which has come about with the rise of stockists and middle-men who don't make anything but miraculously sell products at many times the price of manufacture, as they have no clue about what goes into making what they're selling they have to have a piece of paper in the box with it which they can wave at their customers.
    Large companies also have huge layers of bureaucracy and often require this kind of documentation for parts from outside suppliers.
    There was a time when you quoted for a part based on a spec and delivered that part, at which point the customer would either accept or reject the product.
    If the part is simply machined to their drawing your Certificate of Conformity could refer to the material cert and their drawing for spec with a note stating what process from the drawing is not to be carried out on the part by you, they will then be responsible for collating their drawing, the material cert you supplied and your CoC for downstream customers/compliance departments.

    - Nick
    Last edited by magicniner; 16-02-2016 at 09:09 AM.

  7. #7
    Thank you guys, that's very helpful.


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