I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face across the
disk. That's starting at 0 at one point to doc 0.174
at the opposite side of the 5"o.d. . How would you
do it? Mill? Lathe? How to hold it? Will a four jaw
chuck hold it safely? I'm a bit leery ....
phil k.

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the taper,
hold from outside, and finish boring the hole.

On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just cut the
3" ID in the first place?

As I read the question, the disk will end up 0.375" thick at
one point, and about 0.2005" at a point 5" from the first point.
Phil doesn't say if the OD edge should be perpendicular to a
plane that bisects the finished item, perpendicular to a
remaining original face, or perpendicular to a single new
face.

0.2005 = 0.375 - 5*sin(2 degrees)

--
jiw

On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil Kangas wrote:
I've been presented with an unusual project involving cutting a 2 deg
taper on one side of a disk. The part is mild steel, 3/8 thick, 5"
O.D., with a 3" hole in the center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the taper, hold from
outside, and finish boring the hole.

You beat me to it...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

On Sunday, January 8, 2017 at 7:35:01 PM UTC-8, James Waldby wrote:
On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just cut the
3" ID in the first place?

I was thinking 'taper' meant making the disk into a cone.
So, my answer was for a reversible jaw 3-jaw chuck and workholding
on the lathe to avoid cutting the jaws.

If it means a wedge, the lathe isn't the easiest tool for the facing cut
(though a faceplate and a backing wedge could be arranged).

As I read the question, the disk will end up 0.375" thick at
one point, and about 0.2005" at a point 5" from the first point.

"Phil Kangas" wrote in message
news
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face across the
disk. That's starting at 0 at one point to doc 0.174
at the opposite side of the 5"o.d. . How would you
do it? Mill? Lathe? How to hold it? Will a four jaw
chuck hold it safely? I'm a bit leery ....
phil k.

I'd clamp the square blank to an angled fixture on the mill table. The
fixture could be a bar with a narrow step 0.1746" high, plus thinner
intermediate supports slid in until they jam. A small center hole
would allow redrawing the circles to know how close to the clamps you
need to mill and then to bandsaw the blank roughly round, and help
center it on the lathe.

You could use a 3/16" (0.1875") spacer such as key stock or lathe bits
if the distance between the contact lines is 5.369". You need to mill
two edges of the blank parallel at whatever width the spacer height
requires anyway.

--jsw

"Jim Wilkins" wrote in message
news
"Phil Kangas" wrote in message
news
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face across the
disk. That's starting at 0 at one point to doc 0.174
at the opposite side of the 5"o.d. . How would you
do it? Mill? Lathe? How to hold it? Will a four jaw
chuck hold it safely? I'm a bit leery ....
phil k.

I'd clamp the square blank to an angled fixture on the mill table.
The fixture could be a bar with a narrow step 0.1746" high, plus
thinner intermediate supports slid in until they jam. A small center
hole would allow redrawing the circles to know how close to the
clamps you need to mill and then to bandsaw the blank roughly round,
and help center it on the lathe.

You could use a 3/16" (0.1875") spacer such as key stock or lathe
bits if the distance between the contact lines is 5.369". You need
to mill two edges of the blank parallel at whatever width the spacer
height requires anyway.

--jsw

The same setup would work on a lathe faceplate but I'd hold the blank
with screws in countersunk holes to avoid the rotating clamps.

-jsw

"whit3rd" wrote in message
...
On Sunday, January 8, 2017 at 7:35:01 PM UTC-8, James
Waldby wrote:
On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil
Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in
the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the
taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just
cut the
3" ID in the first place?

I was thinking 'taper' meant making the disk into a cone.
So, my answer was for a reversible jaw 3-jaw chuck and
workholding
on the lathe to avoid cutting the jaws.

If it means a wedge, the lathe isn't the easiest tool for
the facing cut
(though a faceplate and a backing wedge could be
arranged).

This is not a cone, it is a wedge. The cut is only on one
face
of the disk. The cut face is 2 deg off perpendicular to the
center
axis of the hole. It's a nasty work holding situation.


As I read the question, the disk will end up 0.375" thick
at
one point, and about 0.2005" at a point 5" from the first
point.

Yup, you see it correct.
Perhaps one way to do it would be to make a work holding
ring long enough to hold in the mill somehow and cut a
2 deg face on one end. Then tack weld this ring to the
disk of interest and cut that face with the lathe. Make
sense?
More taper disks could then be cut with this setup.

On Monday, January 9, 2017 at 11:29:51 AM UTC-5, Phil Kangas wrote:
"whit3rd" wrote in message
...
On Sunday, January 8, 2017 at 7:35:01 PM UTC-8, James
Waldby wrote:
On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil
Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in
the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the
taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just
cut the
3" ID in the first place?

I was thinking 'taper' meant making the disk into a cone.
So, my answer was for a reversible jaw 3-jaw chuck and
workholding
on the lathe to avoid cutting the jaws.

If it means a wedge, the lathe isn't the easiest tool for
the facing cut
(though a faceplate and a backing wedge could be
arranged).

This is not a cone, it is a wedge. The cut is only on one
face
of the disk. The cut face is 2 deg off perpendicular to the
center
axis of the hole. It's a nasty work holding situation.


As I read the question, the disk will end up 0.375" thick
at
one point, and about 0.2005" at a point 5" from the first
point.

Yup, you see it correct.
Perhaps one way to do it would be to make a work holding
ring long enough to hold in the mill somehow and cut a
2 deg face on one end. Then tack weld this ring to the
disk of interest and cut that face with the lathe. Make
sense?
More taper disks could then be cut with this setup.

If I'm thinking about the geometry correctly, this is how I'd do it: I'd mount it on a lathe faceplate with one edge propped up, and a drawbar pulling a bolt-like piece through the through-hole. Face the disk as close as you can to the central clamp -- whatever you're pulling with the drawbar. Then, without changing the setup, I'd clamp the disk at three or four points around the edge, and withdraw whatever I was holding with the drawbar. Then I'd finish facing the area around the hole.

Or did I just crash something I hadn't thought of? d8-)

--
Ed Huntress

"Phil Kangas" wrote in message
news
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face across the
disk. That's starting at 0 at one point to doc 0.174
at the opposite side of the 5"o.d. . How would you
do it? Mill? Lathe? How to hold it? Will a four jaw
chuck hold it safely? I'm a bit leery ....
phil k.

I'd probably rough it out with CNC on the KMB1 then mount it on a face plate
and turn it further if necessary. Finally I'd cut the hold tabs and cut it
out

"Phil Kangas" wrote in message
news

"whit3rd" wrote in message
...

This is not a cone, it is a wedge. The cut is only on one face
of the disk. The cut face is 2 deg off perpendicular to the center
axis of the hole. It's a nasty work holding situation.


As I read the question, the disk will end up 0.375" thick at
one point, and about 0.2005" at a point 5" from the first point.

Yup, you see it correct.
Perhaps one way to do it would be to make a work holding
ring long enough to hold in the mill somehow and cut a
2 deg face on one end. Then tack weld this ring to the
disk of interest and cut that face with the lathe. Make sense?
More taper disks could then be cut with this setup.

Are the blanks already 5" disks?

If so I think you could hold them at the 2 degree angle in a 4-jaw if
you made a locating jig to go behind them that places them at the
right height and angle.

The jig could be two strips of flat stock joined with threaded rod
into an H shape. The ends would be fitted to stay in place by lightly
contacting the sides of the jaws, or notched to fit over them for a
little more effort.

The tilt plane is at 45 degrees to the jaws so two grab the low side
and the other two the high side, and the strips are widely separated
out near the disk edges.

The strips could be either identically tapered at 2 degrees or
straight at the two heights that tilt the blank to 2 degrees,
depending on which is easier for you to make. Since I have an angle
block set my preference would be to taper them so their spacing isn't
critical.

-jsw

wrote in message
...
On Monday, January 9, 2017 at 11:29:51 AM UTC-5, Phil Kangas wrote:
"whit3rd" wrote in message
...
On Sunday, January 8, 2017 at 7:35:01 PM UTC-8, James
Waldby wrote:
On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil
Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in
the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the
taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just
cut the
3" ID in the first place?

I was thinking 'taper' meant making the disk into a cone.
So, my answer was for a reversible jaw 3-jaw chuck and
workholding
on the lathe to avoid cutting the jaws.

If it means a wedge, the lathe isn't the easiest tool for
the facing cut
(though a faceplate and a backing wedge could be
arranged).

This is not a cone, it is a wedge. The cut is only on one
face
of the disk. The cut face is 2 deg off perpendicular to the
center
axis of the hole. It's a nasty work holding situation.


As I read the question, the disk will end up 0.375" thick
at
one point, and about 0.2005" at a point 5" from the first
point.

Yup, you see it correct.
Perhaps one way to do it would be to make a work holding
ring long enough to hold in the mill somehow and cut a
2 deg face on one end. Then tack weld this ring to the
disk of interest and cut that face with the lathe. Make
sense?
More taper disks could then be cut with this setup.

If I'm thinking about the geometry correctly, this is how I'd do it:
I'd mount it on a lathe faceplate with one edge propped up, and a
drawbar pulling a bolt-like piece through the through-hole. Face the
disk as close as you can to the central clamp -- whatever you're
pulling with the drawbar. Then, without changing the setup, I'd clamp
the disk at three or four points around the edge, and withdraw
whatever I was holding with the drawbar. Then I'd finish facing the
area around the hole.

Or did I just crash something I hadn't thought of? d8-)

--
Ed Huntress

===========

The prop could be a #17 or 11/64" drill bit. I'd want two more props
at right angles to stabilize the disk from wobbling, and something
(wire?) to independently hold the props in place if it does anyway.
You can't tighten the drawbar to clamp everything together while the
faceplate is flat on the bench being assembled.
-jsw

On Monday, January 9, 2017 at 1:34:52 PM UTC-5, Jim Wilkins wrote:
wrote in message
...
On Monday, January 9, 2017 at 11:29:51 AM UTC-5, Phil Kangas wrote:
"whit3rd" wrote in message
...
On Sunday, January 8, 2017 at 7:35:01 PM UTC-8, James
Waldby wrote:
On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil
Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in
the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the
taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just
cut the
3" ID in the first place?

I was thinking 'taper' meant making the disk into a cone.
So, my answer was for a reversible jaw 3-jaw chuck and
workholding
on the lathe to avoid cutting the jaws.

If it means a wedge, the lathe isn't the easiest tool for
the facing cut
(though a faceplate and a backing wedge could be
arranged).

This is not a cone, it is a wedge. The cut is only on one
face
of the disk. The cut face is 2 deg off perpendicular to the
center
axis of the hole. It's a nasty work holding situation.


As I read the question, the disk will end up 0.375" thick
at
one point, and about 0.2005" at a point 5" from the first
point.

Yup, you see it correct.
Perhaps one way to do it would be to make a work holding
ring long enough to hold in the mill somehow and cut a
2 deg face on one end. Then tack weld this ring to the
disk of interest and cut that face with the lathe. Make
sense?
More taper disks could then be cut with this setup.

If I'm thinking about the geometry correctly, this is how I'd do it:
I'd mount it on a lathe faceplate with one edge propped up, and a
drawbar pulling a bolt-like piece through the through-hole. Face the
disk as close as you can to the central clamp -- whatever you're
pulling with the drawbar. Then, without changing the setup, I'd clamp
the disk at three or four points around the edge, and withdraw
whatever I was holding with the drawbar. Then I'd finish facing the
area around the hole.

Or did I just crash something I hadn't thought of? d8-)

--
Ed Huntress

===========

The prop could be a #17 or 11/64" drill bit. I'd want two more props
at right angles to stabilize the disk from wobbling, and something
(wire?) to independently hold the props in place if it does anyway.
You can't tighten the drawbar to clamp everything together while the
faceplate is flat on the bench being assembled.
-jsw

True, which is why I have a stub "fake" spindle (made by my uncle, before he passed his SB 10L on to me) that I clamp in my big vise to do faceplate setups. I have four faceplates, two of them custom-cast, and I used to do a lot of faceplate work when I was doing a lot of home machining, 20 years ago.

Get the setup right in that setup rig, and then take it off the stub and mount it on the lathe. Re-set the drawbar as you had it set up in the vise.

It sounds like a lot of tedium, but if you don't have a mill (I didn't in those days, and I've scrapped the one I did have since), faceplate jobs like that come naturally.

This piece, being only 3/8" thick and 5" diameter, is going to spring if you don't have it well propped-up in the faceplate. It would be a little tricky but a few small scraps of metal, well-placed, should do the job.

--
Ed Huntress

wrote in message
...
On Monday, January 9, 2017 at 1:34:52 PM UTC-5, Jim Wilkins wrote:
wrote in message
...
On Monday, January 9, 2017 at 11:29:51 AM UTC-5, Phil Kangas wrote:
"whit3rd" wrote in message
...
On Sunday, January 8, 2017 at 7:35:01 PM UTC-8, James
Waldby wrote:
On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil
Kangas wrote:
I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in
the
center. Guy wants a 2 deg tapered face

So, bore the hole 2.5", hold from inside, complete the
taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just
cut the
3" ID in the first place?

I was thinking 'taper' meant making the disk into a cone.
So, my answer was for a reversible jaw 3-jaw chuck and
workholding
on the lathe to avoid cutting the jaws.

If it means a wedge, the lathe isn't the easiest tool for
the facing cut
(though a faceplate and a backing wedge could be
arranged).

This is not a cone, it is a wedge. The cut is only on one
face
of the disk. The cut face is 2 deg off perpendicular to the
center
axis of the hole. It's a nasty work holding situation.


As I read the question, the disk will end up 0.375" thick
at
one point, and about 0.2005" at a point 5" from the first
point.

Yup, you see it correct.
Perhaps one way to do it would be to make a work holding
ring long enough to hold in the mill somehow and cut a
2 deg face on one end. Then tack weld this ring to the
disk of interest and cut that face with the lathe. Make
sense?
More taper disks could then be cut with this setup.

If I'm thinking about the geometry correctly, this is how I'd do it:
I'd mount it on a lathe faceplate with one edge propped up, and a
drawbar pulling a bolt-like piece through the through-hole. Face the
disk as close as you can to the central clamp -- whatever you're
pulling with the drawbar. Then, without changing the setup, I'd
clamp
the disk at three or four points around the edge, and withdraw
whatever I was holding with the drawbar. Then I'd finish facing the
area around the hole.

Or did I just crash something I hadn't thought of? d8-)

--
Ed Huntress

===========

The prop could be a #17 or 11/64" drill bit. I'd want two more props
at right angles to stabilize the disk from wobbling, and something
(wire?) to independently hold the props in place if it does anyway.
You can't tighten the drawbar to clamp everything together while the
faceplate is flat on the bench being assembled.
-jsw

True, which is why I have a stub "fake" spindle (made by my uncle,
before he passed his SB 10L on to me) that I clamp in my big vise to
do faceplate setups. I have four faceplates, two of them custom-cast,
and I used to do a lot of faceplate work when I was doing a lot of
home machining, 20 years ago.

Get the setup right in that setup rig, and then take it off the stub
and mount it on the lathe. Re-set the drawbar as you had it set up in
the vise.

It sounds like a lot of tedium, but if you don't have a mill (I didn't
in those days, and I've scrapped the one I did have since), faceplate
jobs like that come naturally.

This piece, being only 3/8" thick and 5" diameter, is going to spring
if you don't have it well propped-up in the faceplate. It would be a
little tricky but a few small scraps of metal, well-placed, should do
the job.

--
Ed Huntress

==============

I made a stub spindle from 2" water pipe, the ID of which will just
barely permit threading 2-1/4 x 8 for light use, like that or checking
the size of likely-looking used chucks and faceplates. The next size
up is 2-3/8 x 6 which is hard to distinguish without measuring tools.
-jsw