SSDave

The Logan should have a standard taper headstock... either MT4 or MT5. 

Not sure what putting a drill chuck in a headstock buys you except for holding very small parts.  If you go that route, just put a chuck with a straight shank in your chuck jaws. 

Respectfully

Mike

Mike,  it is really odd on the 11" and 12" Logans, for some reason they went with a proprietary taper instead of a morse.  I use a jacobs chuck for holding drill bits to drill stocks, and occasionally to drill other things.  I can easily chuck one of the straight shank ones into a 3 jaw I guess, or since I have a complete set of 5C collets and a closer, could just hold bits in a collet.  Just different way than I've done in the past.

Edit:  I see I can order a spindle adapter from the proprietary spindle to #3 MT for $157 from Logan, so that would also be an option.   

Ken,  I have a drawer full of spindle adapters also with many different morse tapers and different jacobs tapers and threads, along with mt to mt adapter sleeves.  I've changed them out many times on chucks.  If they are too stuck to remove otherwise, just open the chuck jaws fully, drill a 5/16" hole in the back of the chuck, and there's a hollow space inside the chuck behind the taper. 
Fill that hole with oil, put a 5/16" drill rod in the hole in the chuck, and strike it with a hammer.  The hydraulic force easily removes the spindle adapter.

Not being a machinist, I don't have a lot of knowledge and experience to draw upon, still think in terms of doing things the way I've always self learned, using the tooling I had.  It's kind of a new thing to me having a wider range of tooling to choose from, and learning better ways to do stuff.

Quick look on the Logan site: Logan 11" Lathes prior to Serial Number 52576 used an internal taper of 1.5730" per foot. after Serial Number 52576 and all 12" and 14" Lathes used an internal taper of 0.8381" per foot. Not too hard to make an adaptor. 

An easier solution; since the Logan’s spindle nose is threaded, get a 2 ¼ TPI backplate and mount a 5C collet chuck on it, just a thought. 

Are you using your lathe as a makeshift drill press?  How do you hold parts in the tailstock?? 

As for the drill chucks,  nice collection… if those are USA made Jacobs “Ball Bearing” chucks, I much prefer them to the Albrecht. The Albrecht’s are pricier, and advertised as being more accurate but won’t hold  nearly as well as a Jacobs Super Chuck,  spin a drill bit in a Albrecht a couple of times and the jaws are toast, then fairly expensive to replace. 
Respectfully

Mike Hunter

Have you considered ER collets & ER Collet chucks?  Lot more forgiving to clamping size than 5C. The  clamping range for a 5c collet is +/- .001,  the clamping range for an ER collet is 1 MM (.039 inch). 

I only use 5C collets for grinding ops or when I have to machine a collet for a custom-made part. 

use a 5c collet to hold the drill in lathe headstock

less runout than drill chuck
also allows short projection on drills with long tangs 
or gun drills
extend a couple times as hole gets deeper
also permits air through 

apply imagination and stand back

Or mount it in the tool post - much easier.

Keep in mind that drills and drill chucks are roughing tools and not precision instruments, and drills will always cut oversize. 

If I want to get fairly precise with a reamer use a good collet, BUT…check the TIR of the collet first.  Had a brand-new imported set that was terrible,  .005 runout.  Tossed them all, bought a set of Crawfords.  Also keep in mind that they have +/- reamers,  my set has + .001, -.001 and dead on.   

So drill undersize, initial ream with the minus reamer check size, and final ream.   

For  precise holes (+/- .0005) in a home shop, you will need to bore it, then lap it with a brass lap. 

.006 on a chuck… not great, but not terrible depending on the chuck size, I’ve got a 20N that I would be surprised if it was less than .010, but again it’s a roughing tool and I only use it for drill bits larger than ½ inch.