Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? I think
I might have to make this spindle on a lathe but it would be nice to
not have to!

cheers,
Jamie

Jamie M fired this volley in news:k42cqe$5hm$1
@speranza.aioe.org:

I think
I might have to make this spindle on a lathe but it would be nice to
not have to!


Break out the lathe, and get to work! Pipes are seldom "straight
threaded", but taper-threaded. A tapered thread wouldn't fit the chuck
properly.

Besides, the US-standard thread for 1-1/2" pipe is 11-1/2tpi. You don't
get up to 8tpi until 2".

LLoyd

"Jamie M" wrote in message
...

Is there an off the shelf pipe I could buy to thread into this and
put
a couple bearings on the pipe to function as the lathe spindle?
Jamie

Not really, other than the headstock from a scrapped lathe. You could
remove the backplate to mount the chuck on the mill table, or buy a
chuck with a 5C mount and a 5C spin index to hold it.
http://www.dontscrapit.com/Californi...ck-partpic.jpg

I made a short 1-1/2" - 8 arbor that fits in a 1" 5C collet to attach
a 1-1/2 - 8 Jacobs chuck to my 2-1/4" - 8 lathe spindle.

On Sep 27, 3:27*pm, Jamie M wrote:
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. *The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? *I think
I might have to make this spindle on a lathe but it would be nice to
not have to!

cheers,
Jamie

1-1/2" x 8 is available thru McMaster Carr as threaded rod (and nuts),
but the thread class fit is 2A. You might want to spend the time
making your own piece where you can get it to fit more to your liking.

On Sep 27, 2:27*pm, Jamie M wrote:
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. *The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? *I think
I might have to make this spindle on a lathe but it would be nice to
not have to!

cheers,
Jamie

It doesn't take long to do once you get set up. I made a dummy
spindle end for making chuck backplates, took an hour or so. That's
NOT a standard fastener or pipe thread. Or you could make a backplate
to fit whatever you're going to hook up the chuck to and fit it to the
chuck in place of the current backplate. Almost as much work as the
dummy spindle nose, I've done both. A three jaw wouldn't have been my
choice for such things, you can tweak a workpiece in a 4 jaw to be a
lot closer on center, but that's me.

Stan

On 9/28/2012 9:39 AM, Stanley Schaefer wrote:
On Sep 27, 2:27 pm, Jamie wrote:
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? I think
I might have to make this spindle on a lathe but it would be nice to
not have to!

cheers,
Jamie

It doesn't take long to do once you get set up. I made a dummy
spindle end for making chuck backplates, took an hour or so. That's
NOT a standard fastener or pipe thread. Or you could make a backplate
to fit whatever you're going to hook up the chuck to and fit it to the
chuck in place of the current backplate. Almost as much work as the
dummy spindle nose, I've done both. A three jaw wouldn't have been my
choice for such things, you can tweak a workpiece in a 4 jaw to be a
lot closer on center, but that's me.

Stan

Hi,

I think I will use some cold rolled steel tube, 1.5" OD and 1" ID, then
put the 8TPI threads onto that, hopefully the tube will work for 1.5" ID
bearings. What type of bearings would be good to use? I probably
will use two bearings I guess and would like to have some axial
pretension to get rid of axial play in the spindle, so need some axial
load as well as radial load bearings. Maybe a single thrust bearing
and a single roller bearing? Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?

cheers,
Jamie

Jamie M fired this volley in news:k459oh$ol$1
@speranza.aioe.org:

Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?


Angular contact with a pre-loading nut.

But don't count on merchant stock tubing being oversized enough to fit
properly. It might be. It might also be a few thou. small.

Buy a piece of "hollow rod" stock suitably oversized, and turn it to fit
the bearings. Then you can also shoulder the piece so the bearings have
something to press against in pre-load.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

Then you can also shoulder the piece so the bearings have
something to press against in pre-load.

I should have said "...bearings on both ends", and the shouldering is
only required on one end, the nut provides the other "shoulder".

But the shaft must fit the inner race diameter with a snug sliding fit or
a bit tighter if you have a press and mandrel to put it on. You're not
likely to get that fit with merchant stock steel sized to the nominal
dimension you want.

LLoyd

"Jamie M" wrote in message
...
... I think I will use some cold rolled steel tube, 1.5" OD and 1"
ID, then
put the 8TPI threads onto that, hopefully the tube will work for
1.5" ID bearings. What type of bearings would be good to use? I
probably
will use two bearings I guess and would like to have some axial
pretension to get rid of axial play in the spindle, so need some
axial
load as well as radial load bearings. Maybe a single thrust bearing
and a single roller bearing? Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?

cheers,
Jamie

What is the point of adding a lathe spindle to a milling table? You
don't need bearings to use it as a rotary index that you clamp TIGHTLY
before making the cut.

Do you already have another lathe to machine this spindle on?

jsw

"Jamie M" wrote in message ...
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? I think
I might have to make this spindle on a lathe but it would be nice to
not have to!



http://www.ebay.com/itm/ATLAS-10-CRA...em416b6a 39b4

On 9/28/2012 4:28 PM, Jim Wilkins wrote:
"Jamie wrote in message
...
... I think I will use some cold rolled steel tube, 1.5" OD and 1"
ID, then
put the 8TPI threads onto that, hopefully the tube will work for
1.5" ID bearings. What type of bearings would be good to use? I
probably
will use two bearings I guess and would like to have some axial
pretension to get rid of axial play in the spindle, so need some
axial
load as well as radial load bearings. Maybe a single thrust bearing
and a single roller bearing? Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?

cheers,
Jamie

What is the point of adding a lathe spindle to a milling table? You
don't need bearings to use it as a rotary index that you clamp TIGHTLY
before making the cut.

Hi,

I'm making something similar to this:

http://www.ebay.com/itm/CNC-Router-R...em3cca2c b47c

cheers,
Jamie



Do you already have another lathe to machine this spindle on?

jsw

On Fri, 28 Sep 2012 21:40:09 -0700, Jamie M wrote:

On 9/28/2012 4:28 PM, Jim Wilkins wrote:
"Jamie wrote in message
...
... I think I will use some cold rolled steel tube, 1.5" OD and 1"
ID, then
put the 8TPI threads onto that, hopefully the tube will work for
1.5" ID bearings. What type of bearings would be good to use? I
probably
will use two bearings I guess and would like to have some axial
pretension to get rid of axial play in the spindle, so need some
axial
load as well as radial load bearings. Maybe a single thrust bearing
and a single roller bearing? Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?

cheers,
Jamie

What is the point of adding a lathe spindle to a milling table? You
don't need bearings to use it as a rotary index that you clamp TIGHTLY
before making the cut.

Hi,

I'm making something similar to this:

http://www.ebay.com/itm/CNC-Router-R...em3cca2c b47c

Cool. How much do you think you can save by making your own? That's
not a bad price point.

--
Never trouble another for what you can do for yourself.
-- Thomas Jefferson

"Larry Jaques" wrote in message
...
On Fri, 28 Sep 2012 21:40:09 -0700, Jamie M wrote:

On 9/28/2012 4:28 PM, Jim Wilkins wrote:
"Jamie wrote in message
...
... I think I will use some cold rolled steel tube, 1.5" OD and 1"
ID, then
put the 8TPI threads onto that, hopefully the tube will work for
1.5" ID bearings. What type of bearings would be good to use? I
probably
will use two bearings I guess and would like to have some axial
pretension to get rid of axial play in the spindle, so need some
axial
load as well as radial load bearings. Maybe a single thrust bearing
and a single roller bearing? Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?

cheers,
Jamie

What is the point of adding a lathe spindle to a milling table? You
don't need bearings to use it as a rotary index that you clamp TIGHTLY
before making the cut.

Hi,

I'm making something similar to this:

http://www.ebay.com/itm/CNC-Router-R...em3cca2c b47c

Cool. How much do you think you can save by making your own? That's
not a bad price point.


About $300. with shipping...

I would probably just buy a harbor freight mini, tossing any un-needed
parts; much sturdier

On Fri, 28 Sep 2012 17:11:47 -0700, "PrecisionmachinisT"
wrote:


"Jamie M" wrote in message ...
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? I think
I might have to make this spindle on a lathe but it would be nice to
not have to!



http://www.ebay.com/itm/ATLAS-10-CRA...em416b6a 39b4

Excellent!! VERY well supplied!


Gunner

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

Jamie M wrote:
On 9/28/2012 9:39 AM, Stanley Schaefer wrote:
On Sep 27, 2:27 pm, Jamie wrote:
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? I
think
I might have to make this spindle on a lathe but it would be nice to
not have to!

cheers,
Jamie

It doesn't take long to do once you get set up. I made a dummy
spindle end for making chuck backplates, took an hour or so. That's
NOT a standard fastener or pipe thread. Or you could make a backplate
to fit whatever you're going to hook up the chuck to and fit it to the
chuck in place of the current backplate. Almost as much work as the
dummy spindle nose, I've done both. A three jaw wouldn't have been my
choice for such things, you can tweak a workpiece in a 4 jaw to be a
lot closer on center, but that's me.

Stan

Hi,

I think I will use some cold rolled steel tube, 1.5" OD and 1" ID, then
put the 8TPI threads onto that, hopefully the tube will work for 1.5"
ID bearings. What type of bearings would be good to use? I probably
will use two bearings I guess and would like to have some axial
pretension to get rid of axial play in the spindle, so need some axial
load as well as radial load bearings. Maybe a single thrust bearing
and a single roller bearing? Or an angular contact bearing and a
roller bearing maybe. Also what is the best mechanism to apply
the axial preloading?

cheers,
Jamie


Jamie,

For a 1.5" x 8tpi threaded spindle I would look at using maybe 2"
bar to start with so you can have an abutment for the chuck threaded
mounting plate to abut against. The various lathes I have used such as
Myford and IIRC Southbend are like this and the location is done by the
abutment and a short plain section next to it before the thread, not the
thread itself. If you look in your chuck you may well find a plain
before the start of the thread. In you chuck case can you remove the
mounting plate? it may need to if possible to true to get the best
running of the plate on your spindle.

Also consider how to lock the chuck from rotating on the spindle so that
cutting forces can't unscrew the chuck.

Also check prices on metric bearings as they are often cheaper due to
larger volumes, shouldn't be an issue if you're making the parts you
make it to the size required.