Anybody know how much a custom bolt would cost?

[Will Collier]

I have been completely unable to find the right sized part for a guitar modification. Thought I had it with a Chinese part from eBay, but three weeks later it showed up and still wasn't right. Anybody know what a metalwork shop would charge me for a pair of small bolts milled to my specs?

(Since somebody is going to ask, I need a bridge stud with an 8mm screw and a ~4mm post.)