M105 lunette question

[Ps3ud0nym]

Hello,
Newbie here to the site and m105. I just recently purchased a m105 and noticed an extrusion with a hole on the lunette body, wondering if anyone can tell me what it is/was. Thanks

 

[Joe Bertram]

Hello,
Newbie here to the site and m105. I just recently purchased a m105 and noticed an extrusion with a hole on the lunette body, wondering if anyone can tell me what it is/was. Thanks

I just always figured it was some sort of casting mark. Will be interesting to see if there's actually a reason

 

[G744]

That is a centering indentation used in a lathe to thread the end that goes into the socket.

 

[gringeltaube]

That is a centering indentation used in a lathe to thread the end that goes into the socket.