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.

Q: Hoping you can help me out. This seems like a technical screw that you may have knowledge on. My customer asked me for a 1/2″-13 x 2″ Long screw FF-S-86 TY IV, QQ-N-281. I’m clear on the size but what does the rest mean? I don’t even know the screw or material?

A: Your customer is asking you for a screw per Military Specification FF-S-86. FF-S-86 covers various types of socket head cap screw fasteners. The TY IV means they want the style listed in the specification as Type IV which is a flat head socket cap screw with a standard 82deg angle. Next QQ-N-281 is a specification that refers to the material Monel 400. This is important to note because it means that the Monel 400 used to make your bolt must adhere to the requirements of specification QQ-N-281. Therefore, your customer requires a Flat Head Socket Cap Screw size 1/2″-13 x 2″ long made out of Monel 400.