MT5 Morse Taper 5 #5 Boring Bar tool holder, holds 7/16 or 13/16 round tool 18L

Description

I dont know much about this thing,
it is Morse Taper 5 MTA5 #5 MT on one end
it is 18 inches long overall
it appears to be a boring bar tool holder that holds a 7/16 or a 13/16 round cutting tool
or a 1/2 square HSS or brazed carbide tool on the end.
the set screws are there. looks like it has been well used and repaired / welded on on the cutting end
it is all one piece, I have no idea why there is a morse taper slot in it, there is nothing to come apart there, maybe someone used that to keep it from spinning even though it has a good tang
it is too big for the tailstock on my lathe
if you know what it is send me a message