Q: My customer is asking me for a hex head that is QQ-N-286 per MIL Spec. Do you know what he is asking for? I’m confused.
A: Yes we can help. First let’s look at the QQ-N-286. This refers to material Monel K500. Monel is a nickel alloy used for high strength saltwater corrosion resistance. For reference it has a sister alloy Monel grade 400 which is signified by QQ-N-281. QQ-N-286 is important to refer to in your quote because this will ensure the Monel K500 used meets certain criteria for this material.
Next let’s move on to your needs for this hex head to be made per a military specification. Typically a specific spec is requested but for a Monel hex head screw, the most common specification used is MIL-DTL-1222. MIL spec MIL-DTL-1222 covers hex head bolts (as well as others) for nickel alloys and other materials. It ensures that the bolt meets specific dimensional criteria. But I would clarify first with your custom if this is the MIL spec they want to use.