I ordered a kit on AliExpress for around 15 euro fourteen days ago and it arrived today! This after my costly mistake of buying a repair kit with the wrong thread distance. That kit had the correct diameter of 10 mm, but the thread width was 1.25 instead of 1.00. Honest mistake, but a 60 euro one.
The kit is complete with drill (better drill perfectly straight, people!), a thread cutter, an applicator (?), a get-the-end-off-tapping thingy and a tiny allen key. The drill is really sharp and that's a good start. First of all you do not want to drill with a blunt drill and having a really sharp one makes things a bit more exciting. Because if you do not drill staight, you're boned.
The thread cutter is a straight forward, single pass cutter and does a good job eating itself thought the previously cut thread. A tiny miracle, because it is not really possible to cut a tighter thread into an existing one. But hey, it worked! It comes with 10 inserts which will last for a while. I assume that I am not repairing threads every single week.
After cutting the new thread I tried to put in one of those inserts and that worked perfectly (yes, still miracle) but the inserts are always too long for our tiny cylinder heads. So what I did is turn it all the way through, so far that the top of the insert is flush with the head. This way the sparkplug gasket ring can close off properly. Now grab a sturby pair of side cutters and clip off the excess on the bottom side and you're done!
You can find this particular cutter right here: http://www.aliexpress.com/item/UNVIERSAL-AUTOMOTIVE-THREAD-REPAIR-HELICAL-COIL-TOOL-KIT-M10-X-1-0-X-13-5MM-AT2059D/32217946257.html It can happen that the item is sold out, then you have to search the website for another one.
Feel free to post questions in the comments!
Stel je vragen in de opmerkingen!