facing off a flat disk....
 

I have an 11 inch diameter 1/4" thick 304 ss disk, no matter what I
try I get chatter, anyone do this? I need both sides flat and
parallel. 4" hole in center. no combination of feeds and speeds got
rid of the chatter. it has some holes through it and they seem to set
up chatter. I was chucked on the OD.

any thoughts?

Tool post grinder? double sticky tape to a rotarty table on the
surface grinder? (grinder not big enough to do the whole thing)
Thank You,
Randy

Remove 333 from email address to reply.

facing off a flat disk....
 

"Randy" wrote in message
...
I have an 11 inch diameter 1/4" thick 304 ss disk, no matter what I
try I get chatter, anyone do this? I need both sides flat and
parallel. 4" hole in center. no combination of feeds and speeds got
rid of the chatter. it has some holes through it and they seem to set
up chatter. I was chucked on the OD.

any thoughts?

Tool post grinder? double sticky tape to a rotarty table on the
surface grinder? (grinder not big enough to do the whole thing)
Thank You,
Randy

Remove 333 from email address to reply.


Tool post grinder with a cup wheel should work well.

Best Regards
Tom.

facing off a flat disk....
 

"Randy" wrote in message
...
I have an 11 inch diameter 1/4" thick 304 ss disk, no matter what I
try I get chatter, anyone do this? I need both sides flat and
parallel. 4" hole in center. no combination of feeds and speeds got
rid of the chatter. it has some holes through it and they seem to set
up chatter. I was chucked on the OD.

Embed the disk in a thin 'tray' of fixturing metal. It should help damp
vibration.

Or... adhesive laminate a sheet of lead to the backside before chucking.

LLoyd

facing off a flat disk....
 

Lloyd E. Sponenburgh wrote:
"Randy" wrote in message
...
I have an 11 inch diameter 1/4" thick 304 ss disk, no matter what I
try I get chatter, anyone do this? I need both sides flat and
parallel. 4" hole in center. no combination of feeds and speeds got
rid of the chatter. it has some holes through it and they seem to set
up chatter. I was chucked on the OD.

Embed the disk in a thin 'tray' of fixturing metal. It should help damp
vibration.

Or... adhesive laminate a sheet of lead to the backside before chucking.

Toolpost grinder.
SFM at the center is going to be much lower than the outside. Hard to
setup a single point cutter for that kind of range.

facing off a flat disk....
 

Rex B wrote:

Lloyd E. Sponenburgh wrote:
"Randy" wrote in message
...
I have an 11 inch diameter 1/4" thick 304 ss disk, no matter what I
try I get chatter, anyone do this? I need both sides flat and
parallel. 4" hole in center. no combination of feeds and speeds got
rid of the chatter. it has some holes through it and they seem to set
up chatter. I was chucked on the OD.

Embed the disk in a thin 'tray' of fixturing metal. It should help damp
vibration.

Or... adhesive laminate a sheet of lead to the backside before chucking.

Toolpost grinder.
SFM at the center is going to be much lower than the outside. Hard to
setup a single point cutter for that kind of range.

That gives me an interesting / odd idea. With the availability of
inexpensive VFDs that at their simplest can take their speed setting
from an analog voltage, it seems it would not be impractical to attach a
sensor to the lathe cross slide or possibly tool holder to setup a
constant linear velocity drive.

Pete C.

facing off a flat disk....
 

....
That gives me an interesting / odd idea. With the availability of
inexpensive VFDs that at their simplest can take their speed setting
from an analog voltage, it seems it would not be impractical to attach a
sensor to the lathe cross slide or possibly tool holder to setup a
constant linear velocity drive.
....
Constant surface speed is a standard item on most newer CNC lathes.

Karl

facing off a flat disk....
 

On Wed, 22 Mar 2006 22:56:54 GMT, "Karl Townsend"
remove .NOT wrote:

...
That gives me an interesting / odd idea. With the availability of
inexpensive VFDs that at their simplest can take their speed setting
from an analog voltage, it seems it would not be impractical to attach a
sensor to the lathe cross slide or possibly tool holder to setup a
constant linear velocity drive.
...
Constant surface speed is a standard item on most newer CNC lathes.

Karl

I assume to some max spindle speed or minimum diameter?

Pete Keillor

facing off a flat disk....
 

"Pete C." wrote:

That gives me an interesting / odd idea. With the availability of
inexpensive VFDs that at their simplest can take their speed setting
from an analog voltage, it seems it would not be impractical to attach a
sensor to the lathe cross slide or possibly tool holder to setup a
constant linear velocity drive.

Pete C.

Not so odd an idea. It's done.

Our newest lathe in the shop at work has a Newall C80 CSS DRO on it.
The CSS stands for constant surface speed, and supposedly allows you to
set a speed and hold it as the diameter changes. Suposedly.
So far we have not been too impressed with that particular setup as it
has only worked intermittently if at all. Reading the manual is
producing little to no useful help. As far as I can see, that particular
system suffers from rather an excess of interlocking safety "features"
that all forget where they were set when the power is shut off at night.

I know that there are others out there than the Colchester/Newall
bunch.


Cheers
Trevor Jones

facing off a flat disk....
 

"Randy" wrote in message
...
I have an 11 inch diameter 1/4" thick 304 ss disk, no matter what I
try I get chatter, anyone do this? I need both sides flat and
parallel. 4" hole in center. no combination of feeds and speeds got
rid of the chatter. it has some holes through it and they seem to set
up chatter. I was chucked on the OD.

any thoughts?

Tool post grinder? double sticky tape to a rotarty table on the
surface grinder? (grinder not big enough to do the whole thing)
Thank You,
Randy

Remove 333 from email address to reply.


I'm a novice so I don't know if this will help.

I had a similar problem only a bit smaller in diameter. It would ring/
oscillate and leave a really crap finish. I clamped it to a "face plate" in
the centre, machined the outer part, clamped the outer then machined the
inner area. I used a fairly slow speed and it turned out ok.
rob