loose in the lifters

[GB SISSON]

I am using Bob Drake hollow adjustable lifters. They came adjusted out about about 1/4" beyond my application. The first two I pulled out of the package felt 'just right' as I cranked them in close to where I needed them. Then I got a really tight one. In my wood jawed cabinet shop vice it was all I could do to keep the lifter from turning along with the bolt. The lower it got the easier it turned. Down at the area I'm using it now also felt just right. Then a couple more good ones and then a way too easy one, in the end 3 loose ones. One I can turn by hand. I have read about this here and found some people put the loose ones in the vice end wise and crunch things a bit. Kinda scary to know how much without damage to lifter. From what I've seen it seems that perhaps the adjusting bolt part has normal threads and the interference part is in the lifter, otherwise the tight ones would become tighter. They all get looser as they run down. Could I just unscrew one and keep the first portions of thread untouched for good starting and maybe a few taps with a small ball peen hammer up higher? Maybe a slight pinch with vice grips? I wish I had an extra to practice with. What exactly are we doing when we compress one of these end-wise in the vice? Does that seem to work well? Sure wish there was room for a normal lock nut!