What's new
What's new

What type of chuck is this?

portista

Plastic
Joined
Oct 19, 2016
Dear Sirs,
I'm buying an used lathe but I was alerted to the fact that this was a special chuck because this one bolted trough its front. This way if I wanted a four independent jaw chuck it would be really hard to find one.
Can you elcuidate me please?
https://postimg.org/image/6ypu9frtb/

Greetings
 
portista

It is difficult to offer much to your question without additional details. But to generalize I offer this.

Lathes generally are made with some "standard spindle nose" such as may be threaded, or the A series, or the D series cam lock, or even the L series long taper spindle nose.. To the spindle is fitted a CHUCK ADAPTOR PLATE that carries the chuck it's self.
Some configurations allow chucks with INTEGRAL ADAPTORS. That is, the chuck back plate is machined to fit directly to the spindle nose. Regardless how one chuck may be fitted, separate adaptor or integral mount, additional jaw chucks can usually be fitted by whichever means is available.

If the chuck is presently mounted with screw fasteners through the front, that will be a way to to mount a new chuck as well. You may need to drill and tap for the new chucks hole pattern. Conversely, it could be that the present mounting is on an adaptor plate.
In any case, do not be concerned, YOU ARE A MACHINIST, WITH A LATHE! You can make what is needed.

Photos or sketches would help with details.
 
A very important thing to understand about any lathe is the type of spindle and chuck mount it has. Here is a link to information on common spindle types: Chuck Mounting Dimensions - Reference Table from Victor Machinery A fourth common spindle type not shown on that link is a simple male thread on the end of the spindle.

Lathe chucks in general either have spindle mounts permanently built into the back of the chuck or are attached to a spindle mount adapter with three or more cap screws.

One of the spindle configurations is the Type A Short Taper. If your lathe has that spindle, your chucks have a tapered recess in the back and attach to the tapped holes in the spindle with cap screws through the front of the chuck. Type A spindles are especially common on large lathes. They are not special, but they are not usually found in home workshops.

In the second case, the cap screws may go into holes drilled through the front of the chuck and attach to tapped holes in the spindle adapter. Or the adapter may have drilled holes and the cap screws attach to tapped holes in the rear of the chuck There is nothing special about either design. You can find chucks made both ways, but the chuck will need to have an adapter to fit your lathe spindle.

Larry
 
Last edited:
*Removing that chuck be sure to mark it so it may be put back in at the very same bolt hole for each bolt as it may be ground in and so would only run true mounted at the same bolt hole and screw hole. A line up mark must be made.
Also mark the mounting plate to the lathe with a line-up mark.

Likely that chuck is mounted to a plate, much like a heavy duty face plate. The face plate of sorts is mounted to the lathe by what ever spindle nose design of the lathe. You may need to take off the chuck to see what design it is that hold the mounting plate to the spindle. .
Then you might just purchase a chuck with not using the plate that adapts that chuck directly to the lathe.
Posting the lath make and model here may be a help. But still even with that, lathe manufacturers offered different spindle nose designs on the same lathe so a look-see is needed.

Yes you might buy a 4jaw and mount it with drilling the purchased chuck but it likely would be better to mount the 4jaw directly to the spindle.
 
That picture doesn't show enough to tell what it is other than a scroll chuck. Got some more pictures with the chuck off of the machine showing the back of it with a scale for reference to its size; myself and many others will probably be able to help.
Dan
 
6ypu9frtb


As others have said - not enough information. List lathe brand and model. Then show some more comprehensive pix of the chuck area from the side and back as well as the front.

But my guess is that socket head capscrew merely holds the chuck together in front of the scroll. Extrapolating from that given the minimal other clues, I's guess it is probably screwed on to a threaded spindle. If you can lock the spindle, try closing the jaws down lightly on a "substantial" flat bar, and try carefully with a modicom of physical force to "unscrew" it. If there is strong resistance, don't over-do it, get some photos and the lathe name info, and report back. It would be best not to use the back gears to lock the spindle, too often they get broken. Again, be careful and don't use excessive force, just "try" it.

smt
 
I'd guess A type simply from the size of the socket head cap screw and the fact that the slotted fillister head screw is possibly holding chuck together

Thumbnails include OP's photo and info related to A type (that go down to 2")
 

Attachments

  • unk chuck.jpg
    unk chuck.jpg
    94.6 KB · Views: 342
  • A and B specs.jpg
    A and B specs.jpg
    96.9 KB · Views: 470
  • A and B more.jpg
    A and B more.jpg
    90.9 KB · Views: 452
The image you posted is a real good shot of the front of the chuck - actually a close up of about 1/3 or 1/4 of the front of the chuck. It shows the mounting screw and two jaws and little else.

From that photo, I find it hard to imagine how that screw and others in a similar position between the other jaws could be mounting it to the spindle if that is a three jaw chuck. They would have to go through the scroll plate. Or be inside a hole in the scroll plate, but even there they would be troublesome. Is that a three jaw or a four jaw chuck?

Chances are that chuck has a back plate, a mounting plate which those screws may be holding it to. That back plate is what actually mounts to the lathe spindle. At least, that is the common method of doing it.

It is actually easier to have holes go completely through an independent, four jaw chuck than through a three jaw one. I have a four jaw that I drilled mounting holes in.

What would help is:

A photo of the rear of the chuck. Frame it so the chuck is the fully shown with a small margin at the top and bottom and the rear of the chuck and the visible parts of the spindle are shown.

A description of the make and model of the lathe.

Photos of the back or mounting surface of any other chucks that are included with the lathe and that will fit on it.
 
Hey guys

I've never seen such a supportive community as this, thank you all for your answers!!!
Since I do not own the lathe I don't have any more pictures. However the model is Celtic mondiale 12.
Is that enough?

Greetings
 
Or a 5 DIN 55022 Bayonet, for the "Mark 2" model, which may explain why the OP notes the unusual chuck mount.

The DIN 55027 has the same dimensions. I think Rohm still makes these, but a new one will probably cost more than the lathe is worth.

For size 5, A = 135mm B=82.575 C=13 D=22, with 4 holes with diameter E=21, and F=104.8

din55027-7.gif
din55027-8.gif


 
Or a 5 DIN 55022 Bayonet, for the "Mark 2" model, which may explain why the OP notes the unusual chuck mount.

The DIN 55027 has the same dimensions. I think Rohm still makes these, but a new one will probably cost more than the lathe is worth.

For size 5, A = 135mm B=82.575 C=13 D=22, with 4 holes with diameter E=21, and F=104.8

din55027-7.gif
din55027-8.gif



Four threaded holes would make fitting a three jaw scroll chuck a real PIA! ;-)
 
portista

The machine in the photo is fitted with an ADAPTOR PLATE.
Can you imagine how difficult it would be to make a lathe spindle with that large diameter feature on the business end.

You need someone local who can better advise you based on a knowledgeable inspection of the machine you are interested in.
 








 
Back
Top