Doc, nice to see you building a pair of lathes!

Don't worry about something having to be a "mod" here, it's only a forum title -- plenty of new project construction here. Besides you ARE modifying some bits of useless metal into a lathe!
Wish I'd seen you earlier in the tailstock work. I would have suggested just super-gluing the tailstock to the base with a few dots of glue while the tailstock bore was on the headstock arbor. That would have aligned the centers and temporarily "tack welded" the tailstock down to the base making it much easier to clamp and drill.
Then you could have just drilled them together, countersunk, and tapped for screws. Before screwing the tailstock down, use a soft hammer to give a slight whack from the side of the tailstock to free the super glue and just scrape it off.
BTW is there some adjustment horizontally for the tailstock for set-over? It's needed for taper cuts, and for truing up the lathe when there's wear on the slide opposite the gibs. I guess a rudimentary form of set-over on a simple lathe could be had by slotting the holes in the tailstock base, instead of needing to locate them so precisely anyway.
You may get some ideas for easing work on your lathe from the couple I've built and written about here. The first is my Gingery lathe, and the second was just a design-as-you-go project, still not completely finished, but 98% there and definitely in use.
https://www.madmodder.net/index.php/topic,8191.0.htmlhttps://www.madmodder.net/index.php/topic,10542.0.htmlGood to see another lathe builder here, and I don't feel so bad about how long I've taken, compared to your 30 years at it!

But ya know, build when you feel like it, and don't when you don't. The point is to enjoy what you do!
