Lathe spindle mod?

This should go well with the thread on grinding chunks out of lathe beds
I'm getting an 'older model' 17" Dean Smith & Grace lathe. It has a 4-stud flange fixing on the spindle, with a central spigot, later versions had camlock or DSG's own version of that.
It's replacing a TOS lathe which has a C-6 (or is it A-6, I'm still confused!) spindle, I've got lots of tooling for that. I had in mind that the DSG spindle could perhaps be modified to take the C-6 stuff, but it now seems it won't be simple. OTOH conversion to C-8 looks like being a doddle. Hole centres on the studs are close enough that a few minutes with a a die grinder or file would be all that's needed. The existing ground locating spigot is just right for shrinking a bit of stock onto, which could then be ground in situ to the proper taper. All that's then needed is a dodge to get a bayonet plate behind the spindle flange, it'll have to be made in two pieces & then screwed or welded together around the spindle. Loose fitting, no question of welding to the spindle.
I reckon it's eminently doable, and the option will still be there of returning to the original setup. The question is though - is it worth it? I don't have any backplates, I would have to try to sell all my C-6 stuff to buy, or make, C-8 replacements. If making, it would be much simpler to make to fit the existing plain flange than to get involved with tapers.
I've no experience of this plain flange type of chuck fixing - any comments from people who have? Obviouly it won't centre the chuck quite as well as a taper, but how much of a problem is that in the real world, given a proper fit on the spindle spigot?

For those who don't know, C-6, A-6 etc have the same spindle nose as D1-6, but use studs or bolts instead of camlock fixings.

Tim

Couldn't you make an adapter that would bolt to the DS&G nose with flush counter bored SHCS on the DS&G pattern and this adaptor would have it's own spigot (tapered as needed) and tapped to match the tooling you wish to use? It would cantilever everything away from the headstock by say 1.5", which is never a good thing.

Couldn't you make an adapter that would bolt to the DS&G nose with flush counter bored SHCS on the DS&G pattern and this adaptor would have it's own spigot (tapered as needed) and tapped to match the tooling you wish to use? It would cantilever everything away from the headstock by say 1.5", which is never a good thing.

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The TOS is probably being scrapped, so it did cross my mind to cut the end off the spindle & adapt it in some way to fit the DSG flange. That would probably work quite well if it were a camlock style, but the DIN C-6 style requires through holes for the studs. Allowing room for this ahead of the existing DSG flange would as you say give a lot of overhang, probably more like 2" extra. I'd be reluctant to lose too much of the rigidity which the massive construction of the DSG gives.
The present DSG arrangement already has more spindle overhang than the camlock or fastlock versions of the same lathe.

Thanks
Tim

Ah...you are wanting to go to camlock. I thought A-6 which is pilot mount and thru bolted. Sorry ol' boy.

Ah...you are wanting to go to camlock. I thought A-6 which is pilot mount and thru bolted. Sorry ol' boy.

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No, perhaps I didn't explain myself very well.
I thought your suggestion might work with camlock, but with the A-6 or C-6 requiring space for a nut behind (ie between the original flange and the new flange) the overhang might be too great. If I went to C-8 I would be using the existing DSG flange, & there would be no extra overhang. Trouble with that is I would have to start from scratch buying or making C-8 backplates.
The lathe comes with just one chuck, so even if I stick to the existing DSG arrangement there's work to be done.
Maybe I could make up a camlock 'false nose' to fit but that wouldn't really enable me to use my existing chucks/backplates fithout converting them to camlock (generally doable).

Tim