so, the impact design severely limits how much you can compress the hammer spring, and its required to modify a few parts to increase tolerance to allow more compression.
I don't know why the impacts have so little ability / range of compression from the factory...and those two parts look like they can be modified by hand tools, and it also looks like there are at least 2 other ways to skin this cat, but I won't bother discussing alternatives as I am not paid for such
52 mil hammer spring? Older is 57 mm...springs don't work based on length alone...that part of the video didn't help explain the requirements or needs for proper hammer weight + spring tuning... Tell me the nominal range of load the spring is under for peak power, is it 5-10 lbs? 10-15 lbs? 20-25 lbs? If this information was more known, it would be easier to consider alternative spring lengths and ratings to achieve a more ideal range suited for ones particular needs...as not all impacts power outputs are equal, neither should their hammer weight or spring setup be equal...