What type of arbor is this?

[jep24601]

This is the arbor off my US Machine Tool Company horizontal mill.
It has no keyways for the cutters and is only 1/2" diameter.
Does it look like someone used it as a surface grinder?
Can I do anything with this arbor or is it junk?

[mc_n_g]

That looks very strange to me.
If it is one of the smaller mills it should be a Brown and Sharpe taper spindle (normally a #9). Looks like someone made that up to fit the spindle.
What is your spindle like??
The is a Burke US Machine group on yahoo.
http://groups.yahoo.com/group/BurkeMills/
US Machine tools was taken over by Burke (if I remember right)
Many of the smaller older machines of that era were B & S taper spindles. The #9 normally uses a 1/2-13 thread drawbar to lock the collet or arbor in place from the back.

[jep24601]

This is it - no separate spindle - this is like a combined spindle & arbor.

On looking at this further I see that there is a possible separation joint which would separate this into a spindle and an arbor but there is no sign of a possible drawbar.

I indicate the possible joint location in the pic below.