Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

It seems to work. I am watching it right now on the webcam, sitting in
the family room. The finishing process with ball mill is tedious, I
set the finishing step to 0.01 inch.

i

Ignoramus8984 wrote:

Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

It seems to work. I am watching it right now on the webcam, sitting in
the family room. The finishing process with ball mill is tedious, I
set the finishing step to 0.01 inch.

i

That would seem to be a better task for a lathe... perhaps you should
try a pyramid... with stone detail... and stairs... kinda Myan... a real
g-code project...

On 2010-07-28, Pete C. wrote:

Ignoramus8984 wrote:

Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

It seems to work. I am watching it right now on the webcam, sitting in
the family room. The finishing process with ball mill is tedious, I
set the finishing step to 0.01 inch.

i

That would seem to be a better task for a lathe... perhaps you should
try a pyramid... with stone detail... and stairs... kinda Myan... a real
g-code project...

Well, I am getting ready to make a particular sprocket.

i

Ignoramus8984 fired this volley in
:

Well, I am getting ready to make a particular sprocket.

Just particular in its general nature, or spectacularly "particular" as to
precision?

G
LLoyd

On 2010-07-28, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus8984 fired this volley in
:

Well, I am getting ready to make a particular sprocket.

Just particular in its general nature, or spectacularly "particular" as to
precision?

I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.

i

On 2010-07-28, Ignoramus8984 wrote:
Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

How about modifying that to mill a projecting cone to fit it?
As long as you have the cone generation capability -- just add a switch
option to define whether it is male or female. (In other words --
generalize the program as much as possible.)

And then test the two against each other -- even in wax.

Hmm ... what happens if you make it larger at the bottom? It
would need a ball end mill which is more of a ball -- not just the
bottom half of the mill. And you would need to be able to tell it what
the diameter of the shank above the ball was so it could predict
interference.

Of course, with such a mill -- you would have a lot of
deflection with a larger diameter cutting section and a skinny shank.
They probably don't make those for metals anyway. :-)

Oh yes -- do you also have the ability to specify conventional
or climb milling? If so -- do the heavy work in conventional, and the
finish cuts in climb which makes a cleaner surface (especially in
aluminum. :-)

It seems to work. I am watching it right now on the webcam, sitting in
the family room. The finishing process with ball mill is tedious, I
set the finishing step to 0.01 inch.

Understood.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
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 ---

On 2010-07-28, DoN. Nichols wrote:
On 2010-07-28, Ignoramus8984 wrote:
Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

How about modifying that to mill a projecting cone to fit it?
As long as you have the cone generation capability -- just add a switch
option to define whether it is male or female. (In other words --
generalize the program as much as possible.)

That would be the next program. But it is not really the same.

Ideally I would like to find a way to mill any pocket given by a
reasonably friendly predicate function p( x, y, z );

And then test the two against each other -- even in wax.

Hmm ... what happens if you make it larger at the bottom? It
would need a ball end mill which is more of a ball -- not just the
bottom half of the mill. And you would need to be able to tell it what
the diameter of the shank above the ball was so it could predict
interference.

I do not really need that

Of course, with such a mill -- you would have a lot of
deflection with a larger diameter cutting section and a skinny shank.
They probably don't make those for metals anyway. :-)

Oh yes -- do you also have the ability to specify conventional
or climb milling? If so -- do the heavy work in conventional, and the
finish cuts in climb which makes a cleaner surface (especially in
aluminum. :-)

sure

i

"Ignoramus8984" wrote in message
...
Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

It seems to work. I am watching it right now on the webcam, sitting in
the family room. The finishing process with ball mill is tedious, I
set the finishing step to 0.01 inch.

I

Seems like an awfully convoluted way to make funnels to transfer all those
leftover chemicals to smaller containers.

Ignoramus8984 fired this volley in
:

I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.


My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"

LLoyd

On 2010-07-28, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus8984 fired this volley in
:

I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.


My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"

No, it is tapered so that the sprocket would lock on the hub.

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.

i

On Wed, 28 Jul 2010 08:20:15 -0500, Ignoramus6705
wrote:

On 2010-07-28, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus8984 fired this volley in
:

I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.


My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"

No, it is tapered so that the sprocket would lock on the hub.

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.

i


Hey Iggy,

In a machine/tool shop, they would probably do the "cone"as you have
done so far, leaving a few thou for finish, then on a Deckel SO (or
similar) would make a tapered carbide cutter, possibly just grind a
"D" type (or even 2 or 4 flutes) to the angle required and then use
that cutter and do the finish circular interpolation using it to give
a "finish" surface.

As this sounds like a kinda small workpiece, or at least if the "hole"
is less than 2 inches, you might even try using a smallish grinding
stone/wheel cut to the correct angle and chucked in a Dremel clamped
to the quill or spindle of the Bridgeport. A "high-speed" attachment
for a mill is a handy thing to have anyway.

Take care.

Brian Lawson,
Bothwell, Ontario.

ps....are you thinking of attending IMTS2010 at the McCormick?
http://www.imts.com/
It's on from September 13 to 18. I might go for one or two days.

Lemme know if you are interested.

On 2010-07-28, Jon Anderson wrote:
On 7/28/2010 3:41 AM, Lloyd E. Sponenburgh wrote:

My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"


I've never seen a rear sprocket that had a tapered seat, but never know
with vintage stuff. However have seen dirt bikes with tapered
countershaft instead of splines. These are very precise tapers, and I
question the ability of a mill to interpolate a sufficiently accurate
taper just in terms of the angle, let alone getting a surface finish
that will do the job. Husqvarna dirt bikes of the 70's for one, used
ground tapers. These could be a real bitch to remove.

Is Iggy just roughing out the taper so it can be more easily ground? Or
trying to generate a finished and functional taper? If it's for
something really rare and not to be ridden or ridden only very gently on
rare occasion, maybe an interpolated taper might hold up. But it would
be wise to consider the possibility of munging up the shaft taper on a
part that might be very hard to come by.

I am assuming front sprocket here as again, have never seen a rear
sprocket seating on a taper.

If the taper can be accurately measured, it can be accurately milled
with a ball end mill. I am not really pretending that I know what I am
doing, but to me the big issue is whether we can measure the taper
with the required degree of accuracy.

We can always test the fit with Prussian blue or something.

i

On 2010-07-28, Brian Lawson wrote:
On Wed, 28 Jul 2010 08:20:15 -0500, Ignoramus6705
wrote:

On 2010-07-28, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus8984 fired this volley in
:

I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.


My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"

No, it is tapered so that the sprocket would lock on the hub.

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.

i


Hey Iggy,

In a machine/tool shop, they would probably do the "cone"as you have
done so far, leaving a few thou for finish, then on a Deckel SO (or
similar) would make a tapered carbide cutter, possibly just grind a
"D" type (or even 2 or 4 flutes) to the angle required and then use
that cutter and do the finish circular interpolation using it to give
a "finish" surface.

As this sounds like a kinda small workpiece, or at least if the "hole"
is less than 2 inches, you might even try using a smallish grinding
stone/wheel cut to the correct angle and chucked in a Dremel clamped
to the quill or spindle of the Bridgeport. A "high-speed" attachment
for a mill is a handy thing to have anyway.

I milled some cones yesterday (in wax), with a ball mill.

My procedure for milling a cone involves, first, roughing out of the
area, and second, doing many circular passes through the material. The
number of passes depends on my parameter fine_finish_zstep.

I milled a cone that was 1 inch deep, and was 1.2 inches diameter on
top and 0.6 inches at the bottom.

For fine_finish_step I picked 0.01, so my mill did 100 passes, with a
0.25" ball end mill, going 0.01" deeper every time.

The result was smooth as if it was turned on a lathe.

Roughing out was relatively quick. I had to stand by with a vacuum to
remove wax chips.

Finishing took quite a while, since I selected a slow feed
speed. About 15 minutes IIRC. It was boring (as in "not fun"), so I
went inside and watched it via the netcam.

ps....are you thinking of attending IMTS2010 at the McCormick?
http://www.imts.com/
It's on from September 13 to 18. I might go for one or two days.

Lemme know if you are interested.

If I get time to go, definitely.

i

On 2010-07-28, Jon Anderson wrote:
On 7/28/2010 5:20 AM, Ignoramus6705 wrote:

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.


Ok, REAL vintage. Ask what year and model, my dad rode and raced Indians
for years. Is it a front or rear sprocket? I'll ask what he knows
(remembers?) about the fit of this taper.

I am pretty sure it is a front sprocket. Whatever you can find out,
will be most gratefully appreciated.

i

Ignoramus6705 wrote:

On 2010-07-28, Jon Anderson wrote:
On 7/28/2010 3:41 AM, Lloyd E. Sponenburgh wrote:

My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"


I've never seen a rear sprocket that had a tapered seat, but never know
with vintage stuff. However have seen dirt bikes with tapered
countershaft instead of splines. These are very precise tapers, and I
question the ability of a mill to interpolate a sufficiently accurate
taper just in terms of the angle, let alone getting a surface finish
that will do the job. Husqvarna dirt bikes of the 70's for one, used
ground tapers. These could be a real bitch to remove.

Is Iggy just roughing out the taper so it can be more easily ground? Or
trying to generate a finished and functional taper? If it's for
something really rare and not to be ridden or ridden only very gently on
rare occasion, maybe an interpolated taper might hold up. But it would
be wise to consider the possibility of munging up the shaft taper on a
part that might be very hard to come by.

I am assuming front sprocket here as again, have never seen a rear
sprocket seating on a taper.

If the taper can be accurately measured, it can be accurately milled
with a ball end mill. I am not really pretending that I know what I am
doing, but to me the big issue is whether we can measure the taper
with the required degree of accuracy.

We can always test the fit with Prussian blue or something.

i

The surface finish of tapered fittings is rather critical. Would you try
to ball mill and R8 collet? Material and heat treat also come into play
for something like this.

Ignoramus6705 fired this volley in
:

It was boring (as in "not fun"), so I
went inside and watched it via the netcam

Heh! That's funny, because it's what I do, too.

I have a wireless IP camera that I've set up with a weighted base.

Sometimes it's watching the mill. Sometimes it's outside next to the
barbeque watching the thermometers!

That last one is especially nice, because I can check on it all night
long without having to trek out to the smoker.

G
LLoyd

On 7/28/2010 3:41 AM, Lloyd E. Sponenburgh wrote:

My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could I
cut that with a tapered reamer instead of milling the hole?"


I've never seen a rear sprocket that had a tapered seat, but never know
with vintage stuff. However have seen dirt bikes with tapered
countershaft instead of splines. These are very precise tapers, and I
question the ability of a mill to interpolate a sufficiently accurate
taper just in terms of the angle, let alone getting a surface finish
that will do the job. Husqvarna dirt bikes of the 70's for one, used
ground tapers. These could be a real bitch to remove.

Is Iggy just roughing out the taper so it can be more easily ground? Or
trying to generate a finished and functional taper? If it's for
something really rare and not to be ridden or ridden only very gently on
rare occasion, maybe an interpolated taper might hold up. But it would
be wise to consider the possibility of munging up the shaft taper on a
part that might be very hard to come by.

I am assuming front sprocket here as again, have never seen a rear
sprocket seating on a taper.

Jon

On 7/28/2010 5:20 AM, Ignoramus6705 wrote:

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.


Ok, REAL vintage. Ask what year and model, my dad rode and raced Indians
for years. Is it a front or rear sprocket? I'll ask what he knows
(remembers?) about the fit of this taper.

Jon

"DoN. Nichols" wrote in message
...

Oh yes -- do you also have the ability to specify conventional
or climb milling? If so -- do the heavy work in conventional, and the
finish cuts in climb which makes a cleaner surface (especially in
aluminum. :-)

I did not know that. Now I'm going to have to run out to the shop and do
some experiments to see. If it's a big enough difference I am going to have
to double the number of MOPs for almost every job when I am laying it out.

"Ignoramus8984" wrote in message
...
Wrote another G code generator function.

Given x and y of the cone center axis, z of the bottom and top, top
and bottom radius, and a few other parameters like finish quality, I
can mill out a vertical cone. I first rough it out quickly, and then
mill the inner surface to desired quality.

It seems to work. I am watching it right now on the webcam, sitting in
the family room. The finishing process with ball mill is tedious, I
set the finishing step to 0.01 inch.

Sounds a bit like overkill. As much as I like to make something I think I
would just buy funnels for transferring all those leftover chemicals to
smaller containers.

On 2010-07-28, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus6705 fired this volley in
:

It was boring (as in "not fun"), so I
went inside and watched it via the netcam

Heh! That's funny, because it's what I do, too.

It is great

I have a wireless IP camera that I've set up with a weighted base.

Sometimes it's watching the mill. Sometimes it's outside next to the
barbeque watching the thermometers!

That last one is especially nice, because I can check on it all night
long without having to trek out to the smoker.

You bet. It is a huge convenience.

i

Jon Anderson wrote:
On 7/28/2010 5:20 AM, Ignoramus6705 wrote:

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.


Ok, REAL vintage. Ask what year and model, my dad rode and raced
Indians for years. Is it a front or rear sprocket? I'll ask what he
knows (remembers?) about the fit of this taper.

Jon

I'm gonna bet it's the sprocket on the transmission output shaft . I've got
a '39 Harley Flathead that uses a tapered fit sprocket (and clutch hub , and
motor sprocket) , mine also incorporates an oil seal into the sprocket .
I'll be boring the hub and machining the seal portion on the lathe . Might
fit a modified sprocket section on my homemade hub , unless I can pick up a
sprocket cutter for "real cheap" .

--
Snag
Wannabe Machinist

On Wed, 28 Jul 2010 07:31:45 -0800, Jon Anderson
wrote:

On 7/28/2010 5:20 AM, Ignoramus6705 wrote:

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.


Ok, REAL vintage. Ask what year and model, my dad rode and raced Indians
for years. Is it a front or rear sprocket? I'll ask what he knows
(remembers?) about the fit of this taper.

Jon


There's a good chance that this bike has a belt driven final drive
with bicycle style sprockets and chain to start it. My curiosity is
peaked anyway.

Newb

On 2010-07-28, Snag wrote:
Jon Anderson wrote:
On 7/28/2010 5:20 AM, Ignoramus6705 wrote:

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.


Ok, REAL vintage. Ask what year and model, my dad rode and raced
Indians for years. Is it a front or rear sprocket? I'll ask what he
knows (remembers?) about the fit of this taper.

Jon

I'm gonna bet it's the sprocket on the transmission output shaft . I've got

I think so.

a '39 Harley Flathead that uses a tapered fit sprocket (and clutch
hub , and motor sprocket) , mine also incorporates an oil seal into
the sprocket . I'll be boring the hub and machining the seal portion
on the lathe . Might fit a modified sprocket section on my homemade
hub , unless I can pick up a sprocket cutter for "real cheap" .


No oil seal here IIRC.

i

On Wed, 28 Jul 2010 10:29:26 -0400, Brian Lawson wrote:
On Wed, 28 Jul 2010 08:20:15 -0500, Ignoramus6705 wrote:
On 2010-07-28, Lloyd E. Sponenburgh wrote:
Ignoramus8984 wrote:
I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.

My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could
I cut that with a tapered reamer instead of milling the hole?"

No, it is tapered so that the sprocket would lock on the hub.

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.

In a machine/tool shop, they would probably do the "cone" as you have
done so far, leaving a few thou for finish, then on a Deckel SO (or
similar) would make a tapered carbide cutter, possibly just grind a "D"
type (or even 2 or 4 flutes) to the angle required and then use that
cutter and do the finish circular interpolation using it to give a
"finish" surface. [or] grinding stone/wheel cut to the correct angle
....

You could use a straight endmill, with the hub mounted on a rotary
table mounted on a sine plate set to the half angle.

--
jiw

On 2010-07-28, Bob La Londe wrote:
"DoN. Nichols" wrote in message
...

Oh yes -- do you also have the ability to specify conventional
or climb milling? If so -- do the heavy work in conventional, and the
finish cuts in climb which makes a cleaner surface (especially in
aluminum. :-)

I did not know that. Now I'm going to have to run out to the shop and do
some experiments to see. If it's a big enough difference I am going to have
to double the number of MOPs for almost every job when I am laying it out.

What happens -- especially in aluminum -- is that the previously
cut chips are forced against the just cut surface and weld themselves
there. With the climb milling (unsafe with heavy cut -- especially on a
worn manual mill and doubly so with pocket milling) the cuts remove the
material and leave a nice clean surface. With the ball screws and the
control from the servo motors, you should not have problems with
reasonable levels of climb milling on your machine.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
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 ---

On 7/28/2010 6:51 AM, Ignoramus6705 wrote:

I am pretty sure it is a front sprocket. Whatever you can find out,
will be most gratefully appreciated.

A year and model would be of great help. And from a previous reply,
while you might be able to generate the general angle by interpolation,
you will in fact, have a series of concentric rings of narrow contact
formed by the cusps of the successive passes. What is likely to happen
if this is ridden much, is the high points will wear or deform,
affecting the fit of the sprocket to the shaft. Any movement at all will
result in fretting and wear of both parts. You are dealing with a
combination of cusp height between milling passes, and the milled finish
itself, which might look smooth to the eye, but is really rough at the
microscopic level. All tapered sprocket bores I've ever seen are ground,
and generally it is the friction of two finely matched surfaces that
transmits the torque. Reduce the surface area in contact due to surface
roughness, and you reduce the torque that can be handled. If however,
this sprocket has a key, that would go a -long- way toward helping your
approach! I don't imagine a 1920's era Indian is going to be flogged,
but with the scarcity and expense of parts, it would be wise to try and
insure the best possible match.

A step over of .001 would improve things quite a bit. But then there's
the issue of just how round a hole can you interpolate on that thing...

I'm certainly not trying to knock what you're doing, just that I foresee
potential problems and that's coming from my combined experience with
machining and motorcycles.


Jon

On 2010-07-29, Jon Anderson wrote:
On 7/28/2010 6:51 AM, Ignoramus6705 wrote:

I am pretty sure it is a front sprocket. Whatever you can find out,
will be most gratefully appreciated.

A year and model would be of great help. And from a previous reply,
while you might be able to generate the general angle by interpolation,
you will in fact, have a series of concentric rings of narrow contact
formed by the cusps of the successive passes. What is likely to happen
if this is ridden much, is the high points will wear or deform,
affecting the fit of the sprocket to the shaft. Any movement at all will
result in fretting and wear of both parts. You are dealing with a
combination of cusp height between milling passes, and the milled finish
itself, which might look smooth to the eye, but is really rough at the
microscopic level. All tapered sprocket bores I've ever seen are ground,
and generally it is the friction of two finely matched surfaces that
transmits the torque. Reduce the surface area in contact due to surface
roughness, and you reduce the torque that can be handled. If however,
this sprocket has a key, that would go a -long- way toward helping your
approach! I don't imagine a 1920's era Indian is going to be flogged,
but with the scarcity and expense of parts, it would be wise to try and
insure the best possible match.

A step over of .001 would improve things quite a bit. But then there's
the issue of just how round a hole can you interpolate on that thing...

I'm certainly not trying to knock what you're doing, just that I foresee
potential problems and that's coming from my combined experience with
machining and motorcycles.

Jon, with a ball endmill, the approximation of a surface is relatively
good even at somewhat larger steps. But I definiteky take your point.

i

DoN. Nichols wrote:
On 2010-07-28, Bob La Londe wrote:

What happens -- especially in aluminum -- is that the previously
cut chips are forced against the just cut surface and weld themselves
there. With the climb milling (unsafe with heavy cut -- especially on a
worn manual mill and doubly so with pocket milling) the cuts remove the
material and leave a nice clean surface. With the ball screws and the
control from the servo motors, you should not have problems with
reasonable levels of climb milling on your machine.

Right, but there is another effect. With conventional milling, the
cutting edge skates along the just-cut material until enough pressure is
produced to bite under the surface. This sliding wears the cutting
edge. I do ALL my work as climb milling now, and so very rarely do I
ever have a cutter wear out, it is great! I do have a CNC machine with
tight screws, and I think Igor does, too.

Jon

On 2010-07-29, Jon Elson wrote:
DoN. Nichols wrote:
On 2010-07-28, Bob La Londe wrote:

What happens -- especially in aluminum -- is that the previously
cut chips are forced against the just cut surface and weld themselves
there. With the climb milling (unsafe with heavy cut -- especially on a
worn manual mill and doubly so with pocket milling) the cuts remove the
material and leave a nice clean surface. With the ball screws and the
control from the servo motors, you should not have problems with
reasonable levels of climb milling on your machine.

Right, but there is another effect. With conventional milling, the
cutting edge skates along the just-cut material until enough pressure is
produced to bite under the surface. This sliding wears the cutting
edge. I do ALL my work as climb milling now, and so very rarely do I
ever have a cutter wear out, it is great! I do have a CNC machine with
tight screws, and I think Igor does, too.

This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

i

Ignoramus5687 wrote:


This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

Yes, you would do the interior of all pockets counterclockwise to climb
mill.

Jon

On 2010-07-30, Jon Elson wrote:
Ignoramus5687 wrote:


This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

Yes, you would do the interior of all pockets counterclockwise to climb
mill.

Very food idea.

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.

i

Ignoramus18915 fired this volley in
:

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.


It boils down to this, Iggy:

Even a complex, path-optimizing package depended at least originally on
the skills of an accomplished machinist to establish the methods and
approaches to a given task.

When you're working at a 'lower level' coding your own toolpaths, your
work will only turn out as good as your machining skills would have
allowed without the computer. All the CNC machine is doing is automating
your personal approach to the task.

LLoyd

Ignoramus18915 wrote:

On 2010-07-30, Jon Elson wrote:
Ignoramus5687 wrote:


This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

Yes, you would do the interior of all pockets counterclockwise to climb
mill.

Very food idea.

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.

i

The key difference with CNC is the lack of interactivity. You have to
plan everything out before the milling begins, unlike manual milling
where you can adapt your speeds and feeds as you go and also monitor the
surface finish and adapt as you get to the finish pass. The spindle
speed override and feed rate override knobs on a typical CNC control are
to allow the machine operator to optimize the process a bit from what
was coded in the G-code. The spindle load meters are also a very useful
item to have and I believe the VFDs all provide for a load meter output.

On 2010-07-30, Pete C. wrote:

Ignoramus18915 wrote:

On 2010-07-30, Jon Elson wrote:
Ignoramus5687 wrote:


This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

Yes, you would do the interior of all pockets counterclockwise to climb
mill.

Very food idea.

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.

i

The key difference with CNC is the lack of interactivity. You have to
plan everything out before the milling begins, unlike manual milling
where you can adapt your speeds and feeds as you go and also monitor the
surface finish and adapt as you get to the finish pass. The spindle
speed override and feed rate override knobs on a typical CNC control are
to allow the machine operator to optimize the process a bit from what
was coded in the G-code. The spindle load meters are also a very useful
item to have and I believe the VFDs all provide for a load meter output.

I think that my VFD does not do that. (current output)

i

Ignoramus18915 fired this volley in
:

I think that my VFD does not do that. (current output)


A guy with some electronics background, three 0.01ohm shunts, and and
handful of op-amps could accomplish that bit of feedback himself. G

LLoyd

Ignoramus18915 wrote:

On 2010-07-30, Pete C. wrote:

Ignoramus18915 wrote:

On 2010-07-30, Jon Elson wrote:
Ignoramus5687 wrote:


This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

Yes, you would do the interior of all pockets counterclockwise to climb
mill.

Very food idea.

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.

i

The key difference with CNC is the lack of interactivity. You have to
plan everything out before the milling begins, unlike manual milling
where you can adapt your speeds and feeds as you go and also monitor the
surface finish and adapt as you get to the finish pass. The spindle
speed override and feed rate override knobs on a typical CNC control are
to allow the machine operator to optimize the process a bit from what
was coded in the G-code. The spindle load meters are also a very useful
item to have and I believe the VFDs all provide for a load meter output.

I think that my VFD does not do that. (current output)

i

Those Toshiba VFDs certainly do, with instructions for it in the manual.
Other VFDs I've looked at also have analog outputs to drive load meters.

On 2010-07-30, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus18915 fired this volley in
:

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.


It boils down to this, Iggy:

Even a complex, path-optimizing package depended at least originally on
the skills of an accomplished machinist to establish the methods and
approaches to a given task.

When you're working at a 'lower level' coding your own toolpaths, your
work will only turn out as good as your machining skills would have
allowed without the computer. All the CNC machine is doing is automating
your personal approach to the task.

This is VERY well put. Exactly. I coded this function to cut a
mold. The mold represents a cone inside a cone:


\___ ___/
\____/

And yet the code to mill it out, while it works is very suboptimal. It
reflects my poor understanding of the process.

i

On 2010-07-30, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus18915 fired this volley in
:

I think that my VFD does not do that. (current output)


A guy with some electronics background, three 0.01ohm shunts, and and
handful of op-amps could accomplish that bit of feedback himself. G

That's beyond me. What it really needs is a power meter. Anyway, I
will try to stick to what I can at least figure out.

i

On 2010-07-30, Pete C. wrote:

Ignoramus18915 wrote:

On 2010-07-30, Pete C. wrote:

Ignoramus18915 wrote:

On 2010-07-30, Jon Elson wrote:
Ignoramus5687 wrote:


This meand that with normal right handed end mills, I would be better
off doing counterclockwise circular cuts when finishing inside circles?

Yes, you would do the interior of all pockets counterclockwise to climb
mill.

Very food idea.

I am realizing that CNC is easy in concept -- "the machine follows
instructions from computer" -- but it is complicated in practice.

i

The key difference with CNC is the lack of interactivity. You have to
plan everything out before the milling begins, unlike manual milling
where you can adapt your speeds and feeds as you go and also monitor the
surface finish and adapt as you get to the finish pass. The spindle
speed override and feed rate override knobs on a typical CNC control are
to allow the machine operator to optimize the process a bit from what
was coded in the G-code. The spindle load meters are also a very useful
item to have and I believe the VFDs all provide for a load meter output.

I think that my VFD does not do that. (current output)

i

Those Toshiba VFDs certainly do, with instructions for it in the manual.
Other VFDs I've looked at also have analog outputs to drive load meters.

I ran out of Toshibas. This is not a Toshiba, it is a TECO FM50 203 or
some such.

i