Re: [Emc-users] Rotary convention

[Gene Heskett]

On Tuesday 19 March 2019 00:11:56 Gene Heskett wrote:

> On Monday 18 March 2019 22:37:13 Stuart Stevenson wrote:
> > Gene,
> >
> > Rotary convention is whatever you want on your machine.
> > To match what a CAD system shows you would rotate the geometry
> > positive by moving in the counter clockwise direction when you view
> > from the X, Y, or Z directions. When you look at the Cartesian
> > coordinate plane laying on your desk, you assume the X axis is
> > pointing to your right, the Y axis is pointing away from you and the
> > Z axis is pointing up. Generally, a positive rotation moves the
> > geometry in a ccw direction.
> >   The normal convention also assigns the label of the rotary tables
> > as follows - A axis rotates around the X axis - B axis rotates
> > around the Y axis and the C axis rotates around the Z axis.
> >   If you mount the rotary table on the left (X negative) end of the
> > XY table (as an A axis) then a positive rotation of the rotary table
> > would result in the top of the table moving toward you.
> >   An A axis that carries the tool would rotate the top away from
> > you. This would be the result the top of the geometry moving toward
> > you but since the rotary table is carrying the tool the top of the
> > tool should move away from you.
> >   All of this is 100% arbitrary. The only requirement is the program
> > numbers and signs match the motion of the machine. Make it
> > comfortable for you and then do it with no apologies to anyone.
> >   Almost every machine control can set the rotation however the shop
> > wants. All the labels are just that labels. You can label any axis
> > whatever you want. The axis Peaches can rotate around the Rutabaga
> > axis for all the machine cares.
> >
> > Regards
> > Stuart
>
> Chuckle, nice way of putting it, and I don't have to reverse anything.
> One thing seems for sure, and thats the speed of this belt drive
> thing, the g0 speed is above 21000 degrees a minute.  That also means
> its a bit soft, with cutting forces moving it a bit. But now I need a
> cbn wheel to shape lathe tools with a gentle touch.

And all I can find on fleabay is huge stuff, way too big (6 to 11") to 
spin with this motor, or teeny stuff mounted for a dremel and its ilk. 
What I'd like is 2", maybe 2.5" in diameter, and nothing in that 
category is mounted, so no arbor.  And most vendors don't know the diff 
between CBN and diamond.

I tried grinding a tool while making the probe stylus and found a 
horrible finish was left by that 80 grit silicon carbide wheel, which 
was markedly improved if the HSS was honed on a 2x6 diamond plate said 
to be 1200 but about worn out.

What I've seen a 5" CBN cup do on the g0704 is a huge improvement but 
takes a week since the g0704's top spindle speed is 2950-3k revs. Needs 
about 10k is the impression I get, but would need to be much better 
balanced and a lot less T.I.R.

Ideas, other sources that don't want $200 and up for such a critter?

Thanks everybody. 

>
> Thanks Stuart.
>
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> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> Cheers, Gene Heskett


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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Re: [Emc-users] Rotary convention

[Gene Heskett]

On Tuesday 19 March 2019 05:38:49 andy pugh wrote:

> On Tue, 19 Mar 2019 at 02:39, Stuart Stevenson  
wrote:
> > The axis Peaches can rotate around the Rutabaga axis for all the
> > machine cares.
>
> Only in the Imperial system. On a metric machine that would be the
> Peach axis rotating about the Swede axis.

;-) Where I grew up, that would have been the pear axis rotating about 
the Iowegian axis. We had quite a few of those up around the Minnesota 
border.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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Re: [Emc-users] Rotary convention

[andy pugh]

On Tue, 19 Mar 2019 at 02:39, Stuart Stevenson  wrote:
>
> The axis Peaches can rotate around the Rutabaga axis for all the
> machine cares.

Only in the Imperial system. On a metric machine that would be the
Peach axis rotating about the Swede axis.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916


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Re: [Emc-users] Rotary convention

[Gene Heskett]

On Monday 18 March 2019 22:37:13 Stuart Stevenson wrote:

> Gene,
>
> Rotary convention is whatever you want on your machine.
> To match what a CAD system shows you would rotate the geometry
> positive by moving in the counter clockwise direction when you view
> from the X, Y, or Z directions. When you look at the Cartesian
> coordinate plane laying on your desk, you assume the X axis is
> pointing to your right, the Y axis is pointing away from you and the Z
> axis is pointing up. Generally, a positive rotation moves the geometry
> in a ccw direction.
>   The normal convention also assigns the label of the rotary tables as
> follows - A axis rotates around the X axis - B axis rotates around the
> Y axis and the C axis rotates around the Z axis.
>   If you mount the rotary table on the left (X negative) end of the XY
> table (as an A axis) then a positive rotation of the rotary table
> would result in the top of the table moving toward you.
>   An A axis that carries the tool would rotate the top away from you.
> This would be the result the top of the geometry moving toward you but
> since the rotary table is carrying the tool the top of the tool should
> move away from you.
>   All of this is 100% arbitrary. The only requirement is the program
> numbers and signs match the motion of the machine. Make it comfortable
> for you and then do it with no apologies to anyone.
>   Almost every machine control can set the rotation however the shop
> wants. All the labels are just that labels. You can label any axis
> whatever you want. The axis Peaches can rotate around the Rutabaga
> axis for all the machine cares.
>
> Regards
> Stuart
>
Chuckle, nice way of putting it, and I don't have to reverse anything. 
One thing seems for sure, and thats the speed of this belt drive thing, 
the g0 speed is above 21000 degrees a minute.  That also means its a bit 
soft, with cutting forces moving it a bit. But now I need a cbn wheel to 
shape lathe tools with a gentle touch.

Thanks Stuart. 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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[Emc-users] Rotary convention

[Stuart Stevenson]

Gene,

Rotary convention is whatever you want on your machine.
To match what a CAD system shows you would rotate the geometry positive by
moving in the counter clockwise direction when you view from the X, Y, or Z
directions. When you look at the Cartesian coordinate plane laying on your
desk, you assume the X axis is pointing to your right, the Y axis is
pointing away from you and the Z axis is pointing up. Generally, a positive
rotation moves the geometry in a ccw direction.
  The normal convention also assigns the label of the rotary tables as
follows - A axis rotates around the X axis - B axis rotates around the Y
axis and the C axis rotates around the Z axis.
  If you mount the rotary table on the left (X negative) end of the XY
table (as an A axis) then a positive rotation of the rotary table would
result in the top of the table moving toward you.
  An A axis that carries the tool would rotate the top away from you. This
would be the result the top of the geometry moving toward you but since the
rotary table is carrying the tool the top of the tool should move away from
you.
  All of this is 100% arbitrary. The only requirement is the program
numbers and signs match the motion of the machine. Make it comfortable for
you and then do it with no apologies to anyone.
  Almost every machine control can set the rotation however the shop wants.
  All the labels are just that labels. You can label any axis whatever you
want. The axis Peaches can rotate around the Rutabaga axis for all the
machine cares.

Regards
Stuart

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