Picked up a Delta Rockwell lathe...and I have a few ???

[Dumb_Polack]

That nut is operated with the wrench on the end of the banjo.  You can find them on Ebay often average $25

Bob10?  Yes, it came with that wrench.

[iclark]

There's a cast sub-base that's supposed to go under the main tailstock casting.



Note:  The locking handle is custom made and not factory.

The cast sub-base is only there for the tailstock when it is there for the headstock. I do not see one.

It looks like the tailstock is sitting on the plate that goes under the ways. I expect that the lock-down nut got lost in some sawdust the last time that it was used. The plate got moved up to the top of the ways so that it would not get lost. Once that plate is placed where it belongs under the ways, you will not need to stack washers.

Not sure what its current market value would be, but I think that you and the seller both got a fair deal (considering that they were liquidating it as part of their father's tools that had not been used in 20+ years). I expect that, for the seller, the thought of their father's lathe becoming a user again instead of being sold as scrap iron was worth as much as the money.

[iclark]

Arlin's suggestion to ask in the turners area is a good one as is the OWWM suggestion.

One caution that you should know about early on is that the tailstock is likely a #2 Morse taper. The gotcha is that not all MT2 accessories are long enough in the taper to be ejected by some of the older tailstocks. If there is no hole in the end of the tailstock spindle crank for a knockout bar, then you need to be really careful to not use an MT2 accessory that cannot be self-ejected by the teilstock.

Crank the tailstock as far back as it will go and, VERY lightly, test the fit of your MT2 accessory. If it centers and feels like it will seat, do NOT seat it. It is too short. If it hits the ejector before it goes all the way in, then you are good to go.

[toolmiser]

I have a little newer model of that lathe -purchased new in 1975 freshman HS. If the ejector doesn't push out the taper, all you have to do is to continue to crank until the tailstock totally is disconnected and the tap thru the hole with something like a piece of dowel and it will release pretty easy. At least it's how mine works.

[TDKPE]

There's a cast sub-base that's supposed to go under the main tailstock casting.

OP: There's a sub-base on ebay for $25 at the moment.  The headstock has no spacer, and bolts directly to the base casting. The drive and dead or live center should line up with each other, at 6" off the bed ways.

That missing sub-base explains the 'thing' that's on the bed ways - it's a key that fits the sub-base, and there are adjusting screws to slide the tail stock laterally across the bed ways to center the spindle on the headstock spindle. Also explains why there is a stack of washers that shouldn't be there.

I've never adjusted mine.  Never needed to, but then, it's normally something that's done at initial assembly and never touched again.

https://www.ebay.com/itm/Delta-Milwaukee...SwsddeYl0f

As to the self-ejecting issue, I've added short extensions to centers to allow them to be ejected.  For ejecting head stock drive centers, use a steel rod (NOT a wooden dowel and hammer), a couple of feet long, and just give a sharp rap.  Should pop right out without damaging the bearings.  Wood is too cushiony and will only cause you to beat up your headstock bearings, but a steel rod will pop it right out.

[toolmiser]

I have one of the "original ejectors" for the headstock. It is metal with a piece of brass on the end. It doesn't take much, I also have a chunk of "allthread" with a plastic knob on it about a foot long, it works fine. I didn't want to say metal on the tailstock or someone would have told me it was too hard on the center.

[mike4244]

Arlin's suggestion to ask in the turners area is a good one as is the OWWM suggestion.

One caution that you should know about early on is that the tailstock is likely a #2 Morse taper. The gotcha is that not all MT2 accessories are long enough in the taper to be ejected by some of the older tailstocks. If there is no hole in the end of the tailstock spindle crank for a knockout bar, then you need to be really careful to not use an MT2 accessory that cannot be self-ejected by the teilstock.

Crank the tailstock as far back as it will go and, VERY lightly, test the fit of your MT2 accessory. If it centers and feels like it will seat, do NOT seat it. It is too short. If it hits the ejector before it goes all the way in, then you are good to go.

Some MT are threaded at the small end. Often comes with a cap screw for adjusting the MT to eject. I believe the thread is 7/16x20. 
I have added small cap bolts to the ends of several MT . To remove a MT that is stuck because it is too short, try this.
Crank the quill out enough to place an adjustable wrench between the quill and the MT. Now crank the quill in. The taper will hit the wrench, used as a spacer and the MT will pop out. The wrench is opened enough so it is a snug fit on the taper. As you crank in the taper hits the wrench and further cranking will pop the MT out of the quill socket.
mike