ARC Threads (pics included)

I got a new ARC-P DS recently. The threads on it felt a bit gritty. I inspected them closely and noticed a significant difference between the threads on older AAA's I had and this one.

I may be losing my mind but I have a vague memory of reading a thread like this in the past, but I could not find it with search.

The two attached pictures and my (crude) drawing below illustrate this. The new unit is on the left. The threads on the new unit seem to be flattened out. They are not sharp like the old unit. The old unit threads are smooth as silk.







I suspect that over time the gritty feeling of the threads will diminish as they get used. I am just concerned that these threads are somehow a mistake or flaw in the manufacturing process and may be easier to cross thread down the road.

I may just be paranoid. I know I have a lifetime warranty, but I would think that a cross threaded head might be considered user error or abuse.

There was a thread on this some time ago--I could not find it either. As I recall, Peter stated that flat threads are smoother and will last as well as pointed threads. He even provided a link to an engineering text verifying this.

I've had a CS with flat threads for over 2 years--almost 3. No issues at all.

I'm guessing the old style threads might actually make it easier to cross thread with sharp edges in essence starting and then cutting the new grooves more easily than dull ones could.

I was wondering about threads myself, but about the compatibility between different head/body combinations, as I have read there differences, maybe problems, between early-mid-late models from ARC LLC, and wonder about combining any of these with parts from MTD LLC.