NH36A - second hand sticking

[Dhahn]

Hi everyone-

I recently acquired a Seiko SXK173, but it wouldn't keep time.  So I decided to take the plunge  and do some modding on my own.

I replaced the movement with a NH36A, new crown and stem, and replaced the crystal with a one that had a date magnifier.  All parts sourced from CrystalTimes.net.

Everything went pretty smooth: I took my time and followed along with the video tutorials.

But here's the thing: the second hand sometimes gets hung up, somewhere between 7 o'clock and 9 o'clock position.  At first I thought the second hand was catching on the minute hand, but it's independent of minute/hour hand position.

If I give the case a tap, sometimes it's enough to get it going again.

I wonder if I cut the stem the wrong length, since it seems to happen less if I leave the crown out.

Any suggestions?

Thanks in advance.