How to build a good and clear supplier approval policy?

I work for an amazing manufacturing company that manufactures joint rolling machines.  This is wild, how these machines started with an idea in someone's head.  There are no set standards yet for my industry, but I used to run a BRC program for a bird food manufacture so I am used to not having cut forward standards.  I look forward to working with all of you to build the best program I can.

I am currently working on building a good and clear supplier approval policy, are there any tips anyone can give me?  What type of items should I include in my supplier scorecard? I am having a couple issues writing this up, as I want to be detailed but not too detailed as to "cut my throat" as my mom says. Thank you all!!

Can you clarify the type of suppliers you need for joint rollers? Are you looking for a way to vet equipment/parts, or something else?

Can you clarify the type of suppliers you need for joint rollers? Are you looking for a way to vet equipment/parts, or something else?

We manufacture the machines, so we take the sheet metal and machine it into usable parts.  our vendor/suppliers consist of Steel yards, Welders, powder coaters, Teflon coating, parts/fasteners from places like Grainger, McMaster carr, etc.  this is why I am having the issues writing this up because technically half of our machines are technically "outsourced processes" which we then take all the finished parts and put them together to create a machine that will make joints for you so it has food contact surfaces (because joints go into your mouth and the smoke goes into your lungs), but not as many as say a beef renderer.  I guess we fall somewhere in between the standards, but consciously I side on the food safety side of things.  I hope this clarifies.