Tool A couple of whatsits

[skippyelwell]

These both came in a crate of old rusty lathe tools, 1st one looks like a cylindrical piece was snapped off where the angle degree marks are.
the second I know is a tail stock centre but why would someone have cut such a large section off of it?
Thanks.

 

[Perry]

The half center could be used when facing center held work. (This is common in watchmaking.)


Here is a link to a watch making site where they make a "half center".
https://watchmaking.weebly.com/tailstock-centers.html

 

[Bandit]

The other, maybe to do with engine valve facing/grinding, appears maybe another degree marking very worn or? on it. I have a very faint memory of something like that on an very old valve grinder. I know, stone wheels too!

 

[skippyelwell]

The other, maybe to do with engine valve facing/grinding, appears maybe another degree marking very worn or? on it. I have a very faint memory of something like that on an very old valve grinder. I know, stone wheels too!

Yeah I can see that, the perpendicular thumb screw holds the face of the valve while the stem is held in the saddle, the style of the casting makes me think early 1900's, model T perhaps.