I actually lengthened the threads for my buddy on both of the draw bars he had. I think they might have been right at the edge of hitting the shoulder, but the problem remained that tightening up the tool in the spindle (we tried both hard tools and collets) was difficult and they only engaged on a very narrow ring near the large end of the taper. I checked one tool by marking it up with a sharpie marker and tightening it, but if you looked at the light scuffs on the various tools they were all the same.
When loosening the draw bar I am used to having to give the draw bar a light tap with a mallet to release the tool. On his machine if you loosening the draw bar 1/2-3/4 of a turn it released the tool with no tap. It just fell out. That was after putting the muscle on wrench against spline wrench to tighten it. I didn't kill it, but I tightened a 1/2 turn further than I normally would have thought was good enough.
There was another issue I couldn't understand. With both of his drawbars there was a little binding as you tightened them up. Enough to cause that annoying wrench/no-wrench affect I hate. I cleaned the threads on the draw bars (obviously since I lengthened them), and cleaned the threads in the tools. Out of the machine they spun together freely. It just made the whole experience of tightening a tool up in the spindle that much more maddening.
In order to get a tool holder or collet to tighten up (his dog pin was removed) I had to hold the tool up into the spindle with enough force that my fingers were almost trembling. On other R8 machines I've never had to do that. Just holding the tool in place normally was more than enough.
The importer (normally very good which is why I have not named them) has been doing the "find one thing in your description of the problem and picking that apart" thing rather than trying to actually address the problem. Either that or saying he doesn't understand the problem. The day before yesterday we shot a video of tightening and loosening some tools and showed the minimal contact ring. I don't know if my buddy has sent the video to them or not yet. Its a brand new machine.
It was sold and marketed and documented as an R8 machine.
Just for the heck of it I took an empty collet, held it in place with a block of wood and smacked the block of wood with a mallet. Several times and as hard as I could swinging upward. Several attempts produced the same result. The collet just fell out. THAT surprised me. Even with a self releasing design that collet should have stuck.
My buddy had done most of this already. (Except lengthening the threads on the draw bars.) I think he just wanted me to try it out and see if I came to the same conclusions he had.