According to Bruce Barnett :
I'm new to metalworking and just got a Microlux 7x14.
I'm interested in machining thin disks - about 1 1/2" in diameter by 1/16".
O.K. What is the spindle nose on that machine?
Looking at an on-line manual tells me that the chuck has three
studs, and you tighten nuts onto the studs to hold it to the spindle
flange. That may mean a special backplate will be needed, as I don't
find that in the list at the site below.
I see that that some lathes have soft jaws, such as
http://www.taigtools.com/c1051.html
Is there an equivalent solution for the Sieg lathe?
Any other ideas?
Here is one vendor of chucks some of which might fit your machine.
http://www.brassandtool.com/Chucks-Lathe.html
Your lathe's model number suggests that it has a 7" swing, which
would normally call for a 3.5" 3-jaw chuck. You could probably get away
with the 4" size, as long as you are careful to not extend the jaws too
far so they hit the ways.
It looks as though what will be the best for you is one of
these:
Bison Front Mount Self Centering Chuck
except that the smaller chucks, (3.25", 3.3" and 4") are not available
with the two-piece jaws. Even the 4.4" one is only available with solid
jaws, and the 5" is the smallest which is available with the two-piece
jaws.
There is another, which may work:
BISON Mini Three Jaw Self Centering Scroll Chuck
with the optional set of one-piece steel soft jaws:
Set of Soft Solid Jaws 7-882-214 $58.00
But -- those chucks are made to fit the Taig, Sherline, and
Unimat machines -- with a threaded spindle. Better, to start with the
Taig chuck, since it has the more useful pie-shaped jaws available, and
they are aluminum, and easier to machine to fit. To read my suggestions
about adapting that, skip to below the line of "+++++" below.
Here is where the backplates for the chucks are listed.
http://www.brassandtool.com/Backplate-Adaptors.html
If they have not yet added one to fit your lathe (which is a
fairly new one in the US, I believe), you will have to get something
like a:
Bison Semi-Machined Rough Opening Adapter
and first machine it to fit your lathe, and then machine the other side
to fit your choice of chuck.
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++
To adapt the Taig chuck, what you will need to do is to first
machine a piece of steel to fit your spindle nose, and fit it with the
proper studs (same metric thread as the ones on the existing chucks).
Then, mount it on the spindle, turn a portion of the length to
the OD for the thread used for the Taig and Sherline chucks (3/4-16
thread.) Make sure to leave a larger diameter to tighten the chuck back
against, and ideally, you should also leave a register diameter behind
the threads to match the register hole in the back of the chuck.
This won't be as strong as a normal 3-jaw chuck with two-piece
jaws, but it should be adequate for your project. And those pie-fan
jaws for the Taig lathe will probably be better for your task than any
soft top jaws available from Bison at present.
The main weak point on the Taig chuck is that you don't have a
key to tighten it. Instead, you have a "tommy bar" to stick in a hole
in the rotating scroll plate on the chuck, and to grip the chuck body
and jaws to keep it from rotating. (There really should be a hole in
the chuck body for a second tommy bar, but there is not one -- at least
on the rather old example which I have.
I hope that this is some help. Now I go to see what others have
answered.
Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. |
http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---