I have these specially made and heat treated. They are made to the highest quality HSS CRYO and are ground by a specialist robot cnc machine that also makes router cutters!
The front face is made 3mm away from the cutting tip allowing to get in tighter to the shoulder.
The extra-long cutter is 16mm dia head which will cut all thread types and up to 70mm long. All shanks are 10mm.
It is possible to cut 130mm long threads by machining a 70mm length thread and then turning the workaround and cutting from the other end! To do this you need to double chuck so make turn a spigot on both ends. Once the first thread is cut and you have swapped the workpiece around, wind it in to match up the cutter to the threads already cut. You might have to micro-adjust to match cutter to the first thread but once done you can then unwind and start cutting the second thread until it matches the first cut. It works as you can see in the bolt pictures!!