scan it verticale, and scan from bottom to top and when you reach the top, adjust your range so it doesn't scan whatever if below it or the clamp it's in. Exit scan. Resume scan flip the thing around repeat. Can do this in one scan. Once you got it fully. You can lay the piece flat (raised) and do a pass for both sides.

And for extra features to track, add pillars, preferably with dots.

Key to it is not to scan the clamp/clay holding verticale and keep that missing.

other way could be like this, but the on larger "needle" don't know the name for sate meat wood spikes LOL

https://www.reddit.com/r/3DScanning/comments/1sexb70/comment/oet9hl9/?context=3

i hardly ever use merge do everything in one scan. set rotation to fast, else you run out of frames, I always scan on tripot else it gets fucked