I had a similar (not identical: mine could be squeezed like a pliar) with
the same problem.
Essentially useless.
It is sad to say, but even in piano tuning, there is a market for tools
that LOOK good, but turn out to not work at all.
Maybe you should ask your mentor, if you have one. Secrets you would
never figure out for yourself: that 's what mentor's are for, no?
(For center pins I used an actual needle, short, firm held in my hand.
But I only had to do a few of them, once in a while.)
hank