My home inspection of Speedmaster heads

The plug type used are the same for the SM’s and the TF’s. I don’t have a pic of a plug installed in the SM’s but here’s what I’m talking about. Radiused, no sharp edges and the plug electrode more exposed. Install a plug and see how the electrode is recessed and the amount of sharp threads are exposed.

View attachment 1715445647

View attachment 1715445648

View attachment 1715445649
I would think sharp edges could cause detonation.