striped threads on oil cooler

[jamesNB]

So I was trying to re-install the oil cooler and the lower line wouldn't go on. I pulled it back out, cleaned up the stud with brake parts cleaner and notice a touch of striped threads at the top of the stud. I tried using the new oil line to get the threads started but no luck.
I don't know if I stripped the threads removing the line, trying to get it back on or more likely, that was why it's been leaking at that spot since I bought it. I thought a new hose would take care of things.
Well, I called the only two machine shops in town and they don't deal with metric sizes. I checked a tool store on the way home and they had a tap and dye set that had an 18mm dye in it (I'm guessing that's the size" but it was $87.
I was planning to run the proper sized die down the threads to clean them out. I think I can handle it but I would rather a machine shop do it. If worst come to worse, I'm thinking they could cut of the old piece and weld/braze a piece of aluminum stock on the cooler and thread it. Anyway, I think it would be cheaper than the $550 for a new oil cooler.
So what do you think?
1. Buy the tap and Die set; clean up the threads myself, making sure everything is nice and level as I cut?
2. Find a big city machine shop that has metric tools and could replace the nipple if needed?
3. Spend the $350 for a new oil cooler?
Anybody try this personally?