Historical gusset detail

[Bill N]

I'm doing some repairs to the original 100 + year old bellows on a Wheatstone Duet, including replacing some gussets.  After carefully removing a gusset I noticed what looks like a 5 or 6 mm notch or cut on each side of the gusset in the "point" that nestles into the valley. (they look more like holes in the photo, but the slit is open at the point end) It looks like this might have been done to allow the gusset to lay flatter around the opening.  Has anyone else noticed this? Was this a standard technique, or an individual piece-worker making life less difficult for her/his self?

Edited January 14, 2021 by Bill N

[Tiposx]

My guess is that’s where a gusset will tend to split when it is worn out. That part in the valley is fully opened and closed around 90 deg. It may also have been weakened a little when pressing it fully into place.

[Frank Edgley]

I'm pretty sure this is from leather drying out, cracking and splitting.

[Bill N]

It looked so neatly done that I hadn't considered that, but I think you both might be right.  In any event, I wasn't planning on duplicating it on the new gussets!