Any 5C adaptor that could fit this?

Or watch ebay.
Karl

That is a very scary item, with legal consequences: ``Can be sued on lathe and grinding machines''.
seriously, thanks.

Bison makes one -- actually two. One with rigid coupling to the backplate and one with the adjust-true feature.
I think that you can at least turn the step on the backplate down to fit the Bison 5C collet chuck -- but I find myself wondering *why*? A L1 spindle nose is certainly large enough to have sufficient spindle bore to accept an adaptor and a drawtube -- ideally a lever closing drawbar for convenience.
The collet chucks have three major disadvantages and one minor in my opinion which is why they are normally used only on lathes with too small a spindle bore to accept a drawtube style closer.
1) The extension takes up some of the distance between the spindle nose and the tailstock center or drill chuck.
2) Because of that extension, there is less rigidity.
3) The runout is typically worse on this than on a proper adaptor -- especially if you don't get an adjust-tru style collet chuck.
4) (minor disadvantage) -- it takes an amazing number of turns of the key to change one collet for another.
However -- if you *really* want the collet chuck, one place which carried them (and from which I have bought Bison chucks and backplates in the past), let's see what they have at the moment:
URL:
7-862-0501 5 inch 3/64 to 1 1/8 10 lbs. $ 350.00 (backplate mount) 7-862-0505 5 inch 3/64 to 1 1/8 12 lbs. $ 495.00 (set-true -- you'l have to modify the backplate quite a bit more.)
There is also one for 16-C which would be a better ftt for the backplate which you have, but 16-C collets -- while they hold a lot larger workpiece, are much more expensive. 5C can be dirt cheap because they are so common.
On this page:

you can find your backplate:
7-879-083 8 inch L1 $ 150.00
While they have direct-mount versions of the collet chuck, there is none for any of the L series spindle noses, and certainly none for as large a spindle as the L2 -- because the spindle chuck is really a poor choice for such a large lathe. It is intended to adapt small lathes to being able to use 5C collets, and is normally not needed for one as large as you have.
Enjoy, DoN.

Don, maybe you are right. Can you point me to an example of a 5C drawtube system?
i

Search eBay for collet closer. There are several, I just looked. You'll most likely PAY to get one for your lathe. Maybe more than your purshase price. But DoN is right, they are nice.
Karl

Well ... for an *example* -- there is what came with my Clausing. A lever at the outboard end of the headstock which operates some levers in a hub to pull the collet in firmly as you operate the lever, and it works through a bearing so the hub can rotate without the lever needing to rotate. Connected to the hub is a tube with an OD of 1-1/4" (on mine -- needs a 1-3/8 bore through the spindle -- yours will handle larger pieces. The tube is hollow, and the end nearest the spindle nose has a female thread to match the outer thread on the end of the collets. The ID must be large enough to pass a 1" diameter workpiece through the spindle. The collets will handle up to 1-1/2" stock -- but only short pieces for sizes over 1" diameter. 1" and smaller will pass all the way through.
At the spindle nose end, there is an adaptor which is a piece of precision hardened steel with a ground finish which fits into the taper of the spindle (in my case Morse taper 4-1/2 -- probably MT-5 or larger for your spindle), with a hole which is a slip fit for the cylindrical part of the collet (and with a pin to keep the collet from rotating in the adapter while you're tightening it. The outboard end of the adaptor has a flange a bit larger than the small end of your L1 spindle nose, so a protector which mounts on the taper can be used for extracting the adaptor when you want to put a chuck back on the spindle.
So -- you put on the nose protector, slap in the nose adaptor (which fits the spindle's internal taper), feed the collet through the nose adaptor, and screw the drawtube onto it (by rotating the hub) until a movement of the lever will firmly grip stock in the collet. Then you flip an item projecting from the hub so it engages notches in the piece permanently attached to the outboard end of the spindle. (This looks like a gear with very shallow teeth, and there may be one on your spindle already.)
The length of the drawtube needs to match the spindle. When I converted my spindle from the original 2-1/4x8 thread to an L-00, I had to make a 1" long extension piece for the drawtube -- one external thread to match the internal at the end of the drawtube and a matching internal thread to accept the collets.
Now -- what I have described is a lever collet closer, which is nicer for production operations, but there are also ones with a bearing and a handwheel on the outboard end of the spindle, which you just screw onto the collet to tighten it, and unscrew to loosen. Not bad, but not as nice as the lever style.
So -- first you'll need to verify what the internal taper is on your spindle. MT-5 is a first guess, but maybe larger. Then you'll need the overall length of the spindle. Then you'll need to either order what you need, or to make your own or find one on eBay and adapt it. The length can be fixed, so one for a shorter spindle can be made to work.
I had to order a new nosepiece and protector from Royal when I got my L-00 spindle -- but I understand that Royal no longer sells these for anything but CNC machines these days. (Scott Logan - is that right?)
The handwheel type is fairly easy to build, if you can get some tube which will fit loosely in the spindle, and which you can internally thread to match the collet thread. The lever system is quite a bit more complex, and it is easier to find and adapt one than to make one from scratch without one to examine.
Haunt e-Bay with the Morse taper and spindle bore and length measurements and you will eventually find one.
Maybe others can point you to someone who still makes them for manual machines.
Enjoy, DoN.

What DoN said. I made my own handwheel type, including the protector. I made the handwheel from aluminum plate, used an aircraft torque tube ball bearing for the thrust bearing, and a tube of almost perfect dimensions of 4140, just had to thread the ends. However, I didn't get the performance I wanted (runout) until I replaced the homemade adapter with one from Royal. Just tell Royal the exact model of your lathe and they'll tell you what adapter. As a bonus, you'll find out what your headstock taper is. Mine wound up being a shortened MT5. Good luck.
Pete Keillor

Get ready for the sticker shock at Royal. iirc, about $1500 for a complete snap-handle system, depending depending.
I have two machines with these snap handles/draw tubes, a Clausing Colchester and an Enco, both 13". The Enco is actually pretty nice bec it has cam lock chucks, making the swap real easy. The CC req's a big-assed spanner wrench, and is a real pita.
Snap handles are very nice, but are more for production. For prototyping, the Bison collet chuck deal Karl showed seems unbeatable for the price, altho mounting it will certainly require some care.

The only part I bought from Royal was the taper adapter. It was expensive, but less than $200 IIRC. The rest is pretty easy to make. I put pics in the dropbox a long time ago. Let's see...
This one has my homemade taper adapter. I never could get less than .001-.002 runout upon reinstallation.
The nose adapter is aluminum, works well. At the time, I didn't have a shaper and hadn't heard of the cross slide as hand shaper trick, filed the keyway.
The handwheel was made of 3/4" al plate, with a separate piece for the hub, bearing carrier is mild steel, tube is 4140.
Pete Keillor

Sort of. Royal Products no longer manufactures the lever operated collet closers, but they do still have many parts. I'm not clear if they are using up old stock or still manufacturing.
We do have a new supplier of US made lever operated collet closers, in case anyone is interested. Drop me an email for details.

Iggy,
I had a "chuck" style closer on my old import because it's spindle bore was too small for 5C.. It was quite adequite and well with in .0005 once I dialed it in, no need for a "tru-set" kinda thingy here. Biggest down side is it's a real pain when you swap collets, and if I had my choice would be last.
Have used "handwheel draw tubes", servicable but a pain, make it a second choice.
Have a Royal "lever draw tube" on the 5914... It's the way to go... Good deals are tough but $125, for all the important pieces is about right... Important pieces includes the splined coller that mounts on the back of the spindle, without that it's just not worth the effort.
I managed to purchase a used Royal lever setup with the spline and tube, that was the correct mount and length for the 5914, but I had to fab the pivot arm.
BTW DoN, I bought the 4.5 morse to 5C on e-bay (it's reasonably common) for $25.00 and made my "nose cover" from scrap AL.
Iggy, you at least need to see some pictures of a lever action, but you really need to see one in action. . --.- Dave

O.K. My only real experience with a 5C collet chuck was on a friend's Logan and it had terrible runout -- but we finally discovered that the spindle nose was bent, and found a replacement on eBay.
However, the key for swapping collets was still terrible -- especially since I was used to a lever style closer on my 12x24" Clausing. :-)
They are not bad on the WW collet spindle for the Unimat SL-1000 and on real jeweler's lathes. I've not used them on larger lathes where the reach is longer.
:-)
I was lucky that my Clausing came with a lever style closer, but I did have to replace the adaptor and nose protector when I replaced the 2-1/4x8 nosed spindle with one with a L-00 nose.
O.K.
Finding the adaptor on eBay would have taken too long at the time (I checked) so I went for the purchase of adaptor and protector from Royal through Scott Logan. (I'm glad to hear that he has a new source -- I just got in under the wire with the Royal ones I think.)
As for making the nose protector, part of the problem was that I had never seen one for the L-00 so I didn't know what I was making. The other part was that I didn't have any scrap large enough for the task at the time.
Even better -- to *use* one. :-)
Enjoy, DoN.