Kelsey Heyes caliper bolt

I have seen them a little different over the years but all were grade 8 like yours or mine. Hemidart67 has one for me.
What are the dimensions of your bolt? I’m going to remove one of mine and ensure I at least have enough threaded portion (which I think I do - I had many many turns of engagement) but would like to know. Just learning mine aren’t original thanks to your post.