Re: [Emc-users] Touching off and Gxx Home positions.

[John Dammeyer]

 
> M30 (and M2(  explicitly sets back to G54.
> http://linuxcnc.org/docs/2.7/html/gcode/m-code.html#mcode:m2-m30

Thanks.
> 
> Maybe use G54 if you are only going to use one?

There's a long story as to why I wanted two. But too involved.  I think once I 
have the Z axis home switch installed for Machine Workspace Home I can 
investigate the others.

John

> 
> --
> 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] Touching off and Gxx Home positions.

[andy pugh]

On Sun, 14 Jul 2019 at 21:17, John Dammeyer  wrote:

One that keeps showing up and confusing me is I'll use my 0.2" diameter
> electronic edge finder.  My DRO knows that it's that diameter so it sets
> the 0 to 0.1" over from where it touches.  I keep forgetting to do that
> with LinuxCNC.  So I'll position the raw material.  Touch it and 0 it from
> the pendant with G55 set.  But then forget to move that 0.1" over and zero
> it again.


You can just set the X / Y / Z to a non-zero value. So if touching-off the
left side, probe to a touch and type -0.05 in the touch-off box.


> I also find I have to edit the G-Code produced by MecSoft CAM to add G55
> but after the M30 LinuxCNC puts it back to G54.  Not sure why and if that's
> the M30 do that
>

M30 (and M2(  explicitly sets back to G54.
http://linuxcnc.org/docs/2.7/html/gcode/m-code.html#mcode:m2-m30

Maybe use G54 if you are only going to use one?

-- 
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] Work holding machining Techniques

[Stuart Stevenson]

Since this is not a production job I would program a nonagressive cutting
regime. I would find some material a little thick (1/2?). I would clamp on
parallels so I could machine the entire periphery and face of the most
precise features. I would then turn the block over and face the block to
thickness and machine the rest of the features.
thanks
Stuart

On Sun, Jul 14, 2019 at 12:35 PM Gene Heskett  wrote:

> On Sunday 14 July 2019 12:11:00 John Dammeyer wrote:
>
> > > -Original Message-
> > > From: Gene Heskett [mailto:ghesk...@shentel.net]
> > > Sent: July-14-19 8:26 AM
> > > To: emc-users@lists.sourceforge.net
> > > Subject: Re: [Emc-users] Work holding machining Techniques
> > >
> > > On Sunday 14 July 2019 09:46:02 andy pugh wrote:
> > > > On Sun, 14 Jul 2019 at 14:43, Roland Jollivet
> > > > 
> > > >
> > > > wrote:
> > > > > Jogging up is better, backlash notwithstanding.
> > > > > Use an accurate rod or the shank of an endmill, say 10mm
> > > > > Jog upwards while you gently try to roll the rod under the
> > > > > cutter
> > > >
> > > > Yes, I should have perhaps gone in to more detail of the
> > > > touch-off. The way you describe is what I do when I want accuracy,
> > > > I use some of my massive stock of broken end-mills as the
> > > > reference.
> > > >
> > > > But for a skim cut to start a job, especually with the big shell
> > > > mill, I often simply jog down until it starts to cut, and call
> > > > that my surface (it soon will be)
> > >
> > > Another technique I've used, works well on the G0704 as its spindle
> > > is well grounded, and when making a "box" of parts, is to plant a
> > > small bit of pcb at some fixed and findable point on the jigging
> > > with super glue, and run the machine to above it.  The top of the
> > > pcb is connected to the probe input, I start the spindle in reverse
> > > so the contact is not destructive either to the copper or the tool,
> > > go down to the probe trip, then back upwards at about 10% of the
> > > down speed until the probe opens. This point is recorded as the
> > > #<_tlo>, and that becomes z=0 for the rest of the time that tool is
> > > in use.  Unforch I've got to figure out a better way on the 6040 as
> > > theres no way, with all the epoxy paint, and apparently ceramic
> > > bearings in the spindle motor to assure a good ground on the tool.
> > > So I've both a spindle mount probe and a contact pad/switch. Now my
> > > problem is a solid mount for it... Due to the wires stiffness, and
> > > its low weight it cannot be convinced to lay dead flat on the table.
> > > Combine that with the lack of a grounded tool needing to have a
> > > ground clipped onto the tool and a PITA is what it is ATM. But I'll
> > > figure out something.
> > >
> > > Just saying there's more than one way to skin this cat.
> > >
> > > Cheers, Gene Heskett
> > > --
> >
> > For my CNC router I use the PCB with a very thin flexible wire
> > soldered to it and to an input on the BoB.  When I press the tool zero
> > button on MACH3 it runs a customized macro I wrote that throws up a
> > dialot telling me to put the ground clip onto the tool.It expects
> > the tool tip to be within a specific distance of the PC board which I
> > lay on top of the work I want as Z Zero.  Once I've done that I click
> > on OK and it goes down probing for contact with the PCB.  After it's
> > found that it adds the PCB thickness to the Z axis position and
> > retracts to the Safe Z location.  Then throws up another dialog
> > telling me to remove the clip from the tool.  Nothing runs until I
> > click OK on that.
> >
> > John
> >
> That should do a good job too, just be aware that you should actually
> measure the thickness of the pcb material to get that offset, I've had
> it vary by over a thou over a 1" x 2" teeny board. First noticed when I
> made micarta pallets to hold the pcb flat as I was carving a circuit.
> The micarta was flat, but the etching was not as consistent as I would
> have liked.  There, the idea is to remove the copper, without digging
> into the glass, which obviously is hell on the etching tool.  Works best
> actually when you have worn a small flat on the end of the tool.  Or I
> have drawn the end of the v-tip across a diamond plate at a slight angle
> designed to make the cut wider by a thou or 2. The end will wear as it
> cuts glass until it no longer cuts the glass but skids in it, while the
> cutting edge still removes the copper.  Tool is finished when you need
> to 4-0 steel wool the board to remove the coppers burrs on side one so
> side 2 will lay flat.
>
> I learned too, that you only drill a thru hole about 3/4 of the board
> thick deep, then run the drill pattern from both sides so it meets
> inside the board and doesn't drill thru, screwing up the pallets
> flatness with a dulling carbide drill. That of course demands .001"
> accuracy. I got that by planting a 1/16" brass contact just outside the
> cutout in the pallet, calibrating where its 

Re: [Emc-users] Work holding machining Techniques

[Gene Heskett]

On Sunday 14 July 2019 12:11:00 John Dammeyer wrote:

> > -Original Message-
> > From: Gene Heskett [mailto:ghesk...@shentel.net]
> > Sent: July-14-19 8:26 AM
> > To: emc-users@lists.sourceforge.net
> > Subject: Re: [Emc-users] Work holding machining Techniques
> >
> > On Sunday 14 July 2019 09:46:02 andy pugh wrote:
> > > On Sun, 14 Jul 2019 at 14:43, Roland Jollivet
> > > 
> > >
> > > wrote:
> > > > Jogging up is better, backlash notwithstanding.
> > > > Use an accurate rod or the shank of an endmill, say 10mm
> > > > Jog upwards while you gently try to roll the rod under the
> > > > cutter
> > >
> > > Yes, I should have perhaps gone in to more detail of the
> > > touch-off. The way you describe is what I do when I want accuracy,
> > > I use some of my massive stock of broken end-mills as the
> > > reference.
> > >
> > > But for a skim cut to start a job, especually with the big shell
> > > mill, I often simply jog down until it starts to cut, and call
> > > that my surface (it soon will be)
> >
> > Another technique I've used, works well on the G0704 as its spindle
> > is well grounded, and when making a "box" of parts, is to plant a
> > small bit of pcb at some fixed and findable point on the jigging
> > with super glue, and run the machine to above it.  The top of the
> > pcb is connected to the probe input, I start the spindle in reverse
> > so the contact is not destructive either to the copper or the tool,
> > go down to the probe trip, then back upwards at about 10% of the
> > down speed until the probe opens. This point is recorded as the
> > #<_tlo>, and that becomes z=0 for the rest of the time that tool is
> > in use.  Unforch I've got to figure out a better way on the 6040 as
> > theres no way, with all the epoxy paint, and apparently ceramic
> > bearings in the spindle motor to assure a good ground on the tool.
> > So I've both a spindle mount probe and a contact pad/switch. Now my
> > problem is a solid mount for it... Due to the wires stiffness, and
> > its low weight it cannot be convinced to lay dead flat on the table.
> > Combine that with the lack of a grounded tool needing to have a
> > ground clipped onto the tool and a PITA is what it is ATM. But I'll
> > figure out something.
> >
> > Just saying there's more than one way to skin this cat.
> >
> > Cheers, Gene Heskett
> > --
>
> For my CNC router I use the PCB with a very thin flexible wire
> soldered to it and to an input on the BoB.  When I press the tool zero
> button on MACH3 it runs a customized macro I wrote that throws up a
> dialot telling me to put the ground clip onto the tool.It expects
> the tool tip to be within a specific distance of the PC board which I
> lay on top of the work I want as Z Zero.  Once I've done that I click
> on OK and it goes down probing for contact with the PCB.  After it's
> found that it adds the PCB thickness to the Z axis position and
> retracts to the Safe Z location.  Then throws up another dialog
> telling me to remove the clip from the tool.  Nothing runs until I
> click OK on that.
>
> John
>
That should do a good job too, just be aware that you should actually 
measure the thickness of the pcb material to get that offset, I've had 
it vary by over a thou over a 1" x 2" teeny board. First noticed when I 
made micarta pallets to hold the pcb flat as I was carving a circuit. 
The micarta was flat, but the etching was not as consistent as I would 
have liked.  There, the idea is to remove the copper, without digging 
into the glass, which obviously is hell on the etching tool.  Works best 
actually when you have worn a small flat on the end of the tool.  Or I 
have drawn the end of the v-tip across a diamond plate at a slight angle 
designed to make the cut wider by a thou or 2. The end will wear as it 
cuts glass until it no longer cuts the glass but skids in it, while the 
cutting edge still removes the copper.  Tool is finished when you need 
to 4-0 steel wool the board to remove the coppers burrs on side one so 
side 2 will lay flat.

I learned too, that you only drill a thru hole about 3/4 of the board 
thick deep, then run the drill pattern from both sides so it meets 
inside the board and doesn't drill thru, screwing up the pallets 
flatness with a dulling carbide drill. That of course demands .001" 
accuracy. I got that by planting a 1/16" brass contact just outside the 
cutout in the pallet, calibrating where its center was at, per pallet 
and offsetting the co-ords to fit.

Slow work on a std mill, with its slow spindle limiting cutting speeds 
and one of the reasons I bought the 6040 with it's 24k revs spindle. 
Rapids are much faster too. Unforch. the bed is nowhere near flat enough 
for that level of work, so I'm debating on how best to replace it with 
something stronger and flatter.

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)
If we desire respect 

Re: [Emc-users] Work holding machining Techniques

[John Dammeyer]

> On Sun, 14 Jul 2019 at 03:25, John Dammeyer 
> wrote:
> 
> >
> > Work holding is the issue.  What's an ideal process?
> 
> 
> If you are making one, what I would do is:
> Machine to width and length.
> Clamp in the vice supported by parallels [1]. Possibly with a bit of
> polystyrene packing or a loop of cable tie or similar to keep the parallels
> from wandering.
> Skim the top surface, Machine the slots all the way through (or not quite
> all the way through if a parallel is in the way. Drill the holes deep
> enough to meet the rebate.
> Turn over in the vice and use parallels that allow the rebate to be
> machined, skim to finished thickness (opening up the slots if not milled
> through) and mill the rebate.
> 
> If there were features on the other side that needed to be positioned then
> I would have the G-code origin for that side be one of the through-hole
> centres and would probe that for the second ops.
> 
> [1] It's well worth getting a set or parallels, I have these:
> https://www.amadeal.co.uk/acatalog/Precision-Parallel-Set-8pair-set-
> 8x120mm-AMA_AC_637_7972TD.html
> though I imagine you would look for a set closer to home, and would be
> able
> to pay rather less.


Thanks Andy,
I have two sets of parallels.  One with a few scars and a brand new set still 
in the wrapper.

I was starting with material that was already 0.375" thick so the idea of 
protecting the parallels by not drilling/milling all the way through had not 
occurred to me.  Flipping over and then surfacing to final thickness to expose 
the holes/slots is an interesting approach.   Thanks.

The other suggestion where the raw material is  hanging it out the end is what 
I did for the switch mounts.   I placed a support under the  end to keep it 
from flexing downwards.  Photo attached.  These are now attached to the cover 
over the Y axis DRO Scale and I have consistent homing on Y and X now.

One of these switch holders will also be screwed to the base plate I asked 
about.  The rabbet on the underside of that base plate is there to clear the 
casting as it curves towards the dovetail ways and would not make the base sit 
flat.  

There doesn't seem to be much point to making a Z axis limit switch since that 
limit will change depending on what tool is loaded and if there's a vice or 
rotary table on the mill.   Unless there's some way that a tool change 
operation can change the soft limit for -Z.  And even then, work held in a 
rotary table 3 jaw chuck might have chuck jaws higher than the workpiece so a 
-Z limit would be counterproductive.  However, an absolute one tied to the tool 
length to forever protect scarring the mill table would be nice.  

John

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Re: [Emc-users] Work holding machining Techniques

[John Dammeyer]

> -Original Message-
> From: Gene Heskett [mailto:ghesk...@shentel.net]
> Sent: July-14-19 8:26 AM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Work holding machining Techniques
> 
> On Sunday 14 July 2019 09:46:02 andy pugh wrote:
> 
> > On Sun, 14 Jul 2019 at 14:43, Roland Jollivet
> > 
> >
> > wrote:
> > > Jogging up is better, backlash notwithstanding.
> > > Use an accurate rod or the shank of an endmill, say 10mm
> > > Jog upwards while you gently try to roll the rod under the cutter
> >
> > Yes, I should have perhaps gone in to more detail of the touch-off.
> > The way you describe is what I do when I want accuracy, I use some of
> > my massive stock of broken end-mills as the reference.
> >
> > But for a skim cut to start a job, especually with the big shell mill,
> > I often simply jog down until it starts to cut, and call that my
> > surface (it soon will be)
> 
> Another technique I've used, works well on the G0704 as its spindle is
> well grounded, and when making a "box" of parts, is to plant a small bit
> of pcb at some fixed and findable point on the jigging with super glue,
> and run the machine to above it.  The top of the pcb is connected to the
> probe input, I start the spindle in reverse so the contact is not
> destructive either to the copper or the tool, go down to the probe trip,
> then back upwards at about 10% of the down speed until the probe opens.
> This point is recorded as the #<_tlo>, and that becomes z=0 for the rest
> of the time that tool is in use.  Unforch I've got to figure out a
> better way on the 6040 as theres no way, with all the epoxy paint, and
> apparently ceramic bearings in the spindle motor to assure a good ground
> on the tool. So I've both a spindle mount probe and a contact
> pad/switch. Now my problem is a solid mount for it... Due to the wires
> stiffness, and its low weight it cannot be convinced to lay dead flat on
> the table. Combine that with the lack of a grounded tool needing to have
> a ground clipped onto the tool and a PITA is what it is ATM. But I'll
> figure out something.
> 
> Just saying there's more than one way to skin this cat.
> 
> Cheers, Gene Heskett
> --

For my CNC router I use the PCB with a very thin flexible wire soldered to it 
and to an input on the BoB.  When I press the tool zero button on MACH3 it runs 
a customized macro I wrote that throws up a dialot telling me to put the ground 
clip onto the tool.It expects the tool tip to be within a specific distance 
of the PC board which I lay on top of the work I want as Z Zero.  Once I've 
done that I click on OK and it goes down probing for contact with the PCB.  
After it's found that it adds the PCB thickness to the Z axis position and 
retracts to the Safe Z location.  Then throws up another dialog telling me to 
remove the clip from the tool.  Nothing runs until I click OK on that.

John



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Re: [Emc-users] Work holding machining Techniques

[John Dammeyer]

> -Original Message-
> From: Roland Jollivet [mailto:roland.jolli...@gmail.com]
> Sent: July-14-19 6:41 AM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] Work holding machining Techniques
> 
> > G0 X10 Y100 (equivalent to positioning by DRO)
> > jog down to kiss the material "Touch Off" Z (equivalent to zeroing the
> DRO)
> >
> 
> It's often suggested to jog down to touch off. Maybe onto some paper or
> whatever.
> I think it's a bad idea because of the risk of chipping the flutes, and in
> the last 0.3mm it's difficult to gauge where you are.
> 
> Jogging up is better, backlash notwithstanding.
> Use an accurate rod or the shank of an endmill, say 10mm
> Jog upwards while you gently try to roll the rod under the cutter
> As you near the crest of the rod you can see when you need to reduce the
> increment
> And if you overshoot, it's easy enough to lower and do it again
> 
> Roland

Thanks. Good technique to add to my how to do things tool box.
John




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Re: [Emc-users] Work holding machining Techniques

[Gene Heskett]

On Sunday 14 July 2019 09:46:02 andy pugh wrote:

> On Sun, 14 Jul 2019 at 14:43, Roland Jollivet
> 
>
> wrote:
> > Jogging up is better, backlash notwithstanding.
> > Use an accurate rod or the shank of an endmill, say 10mm
> > Jog upwards while you gently try to roll the rod under the cutter
>
> Yes, I should have perhaps gone in to more detail of the touch-off.
> The way you describe is what I do when I want accuracy, I use some of
> my massive stock of broken end-mills as the reference.
>
> But for a skim cut to start a job, especually with the big shell mill,
> I often simply jog down until it starts to cut, and call that my
> surface (it soon will be)

Another technique I've used, works well on the G0704 as its spindle is 
well grounded, and when making a "box" of parts, is to plant a small bit 
of pcb at some fixed and findable point on the jigging with super glue, 
and run the machine to above it.  The top of the pcb is connected to the 
probe input, I start the spindle in reverse so the contact is not 
destructive either to the copper or the tool, go down to the probe trip, 
then back upwards at about 10% of the down speed until the probe opens. 
This point is recorded as the #<_tlo>, and that becomes z=0 for the rest 
of the time that tool is in use.  Unforch I've got to figure out a 
better way on the 6040 as theres no way, with all the epoxy paint, and 
apparently ceramic bearings in the spindle motor to assure a good ground 
on the tool. So I've both a spindle mount probe and a contact 
pad/switch. Now my problem is a solid mount for it... Due to the wires 
stiffness, and its low weight it cannot be convinced to lay dead flat on 
the table. Combine that with the lack of a grounded tool needing to have 
a ground clipped onto the tool and a PITA is what it is ATM. But I'll 
figure out something.

Just saying there's more than one way to skin this cat.

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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Work holding machining Techniques

[andy pugh]

On Sun, 14 Jul 2019 at 14:43, Roland Jollivet 
wrote:

>
> Jogging up is better, backlash notwithstanding.
> Use an accurate rod or the shank of an endmill, say 10mm
> Jog upwards while you gently try to roll the rod under the cutter
>

Yes, I should have perhaps gone in to more detail of the touch-off.
The way you describe is what I do when I want accuracy, I use some of my
massive stock of broken end-mills as the reference.

But for a skim cut to start a job, especually with the big shell mill, I
often simply jog down until it starts to cut, and call that my surface (it
soon will be)

-- 
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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[Emc-users] Work holding machining Techniques

[Roland Jollivet]

> G0 X10 Y100 (equivalent to positioning by DRO)
> jog down to kiss the material "Touch Off" Z (equivalent to zeroing the DRO)
>

It's often suggested to jog down to touch off. Maybe onto some paper or
whatever.
I think it's a bad idea because of the risk of chipping the flutes, and in
the last 0.3mm it's difficult to gauge where you are.

Jogging up is better, backlash notwithstanding.
Use an accurate rod or the shank of an endmill, say 10mm
Jog upwards while you gently try to roll the rod under the cutter
As you near the crest of the rod you can see when you need to reduce the
increment
And if you overshoot, it's easy enough to lower and do it again

Roland

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Re: [Emc-users] Work holding machining Techniques

[andy pugh]

On Sun, 14 Jul 2019 at 09:45, John Dammeyer  wrote:

Before I removed the handles I'd have done a drawing of the part and with
> the DRO for guidance already had one cut.


You don't need G-code files.  The equivalent of your DRO + handles is MDI.

G0 X10 Y100 (equivalent to positioning by DRO)
jog down to kiss the material "Touch Off" Z (equivalent to zeroing the DRO)
G1 F30 Z-6 (equivalent to winding down to the cut depth)
G1 F80 X-100 (Equivalent to engaging the power feed)

-- 
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] Work holding machining Techniques

[andy pugh]

On Sun, 14 Jul 2019 at 03:25, John Dammeyer  wrote:

>
> Work holding is the issue.  What's an ideal process?


If you are making one, what I would do is:
Machine to width and length.
Clamp in the vice supported by parallels [1]. Possibly with a bit of
polystyrene packing or a loop of cable tie or similar to keep the parallels
from wandering.
Skim the top surface, Machine the slots all the way through (or not quite
all the way through if a parallel is in the way. Drill the holes deep
enough to meet the rebate.
Turn over in the vice and use parallels that allow the rebate to be
machined, skim to finished thickness (opening up the slots if not milled
through) and mill the rebate.

If there were features on the other side that needed to be positioned then
I would have the G-code origin for that side be one of the through-hole
centres and would probe that for the second ops.

[1] It's well worth getting a set or parallels, I have these:
https://www.amadeal.co.uk/acatalog/Precision-Parallel-Set-8pair-set-8x120mm-AMA_AC_637_7972TD.html
though I imagine you would look for a set closer to home, and would be able
to pay rather less.

-- 
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] Work holding machining Techniques

[John Dammeyer]

> 
> How bit is the part?
> If your stock is a solid bar, or you can use a bar (BMS?) then just clamp
> the whole bar in the vise, with enough material to the side of the vise.
> Mill the overhang, flip, mill.
> Then cut it off and skim the cut face.
> 
It's 1.2"x 3".  So the bar idea is a good one.  What I found from my research 
before I posted the question was that there's lots of stuff out there on how to 
use a vise or other work holding features.  But when it comes down to producing 
a small part or bracket there's less educational material on it.  
There is one Youtube series from someone named "oxtoolco" that appear to be 
quite good.  But he's got hours and hours.  It will take a while.

For now I've 3D printed the part to see how it will fit and if I've missed 
something.  Then I can decide if I want to try some more LinuxCNC carving.  
Before I removed the handles I'd have done a drawing of the part and with the 
DRO for guidance already had one cut.   Not that hard when it's only straight 
cuts.  Add curves and we're back to needing CNC.

Until one has experience it's hard to know in what order to do the machining.

John





> 
> 



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[Emc-users] Work holding machining Techniques

[Roland Jollivet]

How bit is the part?
If your stock is a solid bar, or you can use a bar (BMS?) then just clamp
the whole bar in the vise, with enough material to the side of the vise.
Mill the overhang, flip, mill.
Then cut it off and skim the cut face.



On Sun, 14 Jul 2019 at 04:25, John Dammeyer  wrote:

> The attached picture shows a small knee Z axis switch plate mount to bolt
> onto my mill and cut with LinuxCNC.  The slotted holes are to allow it to
> move the switch assembly closer or further away from the knee.  The two
> small holes will be threaded to hold the switch plate which can move up and
> down it's slots to adjust the actual knee home position.
>
> Drawing is done.  CAM is done.  G-Code generated. Home is the bottom left
> corner.  Ultimately I'll have a profiling operation that adds a radius to
> the corners.  And I have to mill the rabbet on the bottom.
>
> Work holding is the issue.  What's an ideal process?   Clamp a slightly
> oversize piece in the vise and have the CNC drill the holes and mill the
> two slots?  Then clamp it upside  down onto a piece of MDF using the two
> slots as the place for the hold down bolts?  Then run the profile and
> rabbet code?
>
> Or is it better to drill a couple of holes first in approximately the
> correct location of the slots and profile first.  Then flip it and in the
> vise do the rest of the milling?  No need to try and line it up twice.
>
> Or maybe drill two mounting holes, then bolt it to a rectangular piece and
> clamp that in the vise so it's above the jaws.  Then profile and do the
> holes at the same time?  Still needs to be flipped for the rabbet but then
> it could be referenced to the fixed jaw corner for Home Position.
>
> Suggestions?
> Thanks
> John
>
>
>
>
>
>
> > -Original Message-
> > From: Gene Heskett [mailto:ghesk...@shentel.net]
> > Sent: July-11-19 7:02 PM
> > To: emc-users@lists.sourceforge.net
> > Subject: Re: [Emc-users] .ini file questions
> >
> > On Thursday 11 July 2019 13:12:17 John Dammeyer wrote:
> >
> > > > The value "HOME_OFFSET=" is the number value given to the point
> > > > where the home switch changes during the home_latch move.
> > > > The value "HOME=" is the position the joint will move to (relative
> > > > to the "HOME_OFFSET=" point) at the feed rate specified by
> > > > "HOME_FINAL_VEL=".
> > > >
> > > > So If you're using your negative limit switch as the home switch,
> > > > and specify HOME_OFFSET=-1 and HOME=0 after probing the switch the
> > > > axis will move to 1" (or 1mm) away from the switch with that point
> > > > given the value of 0 in the g53 machine coordinates.  If you were to
> > > > set HOME_OFFSET=0 and HOME=1, the point the machine would stop
> > would
> > > > still be the same but that position would now be given the value of
> > > > 1 in the machine coordinates.
> > > >
> > > > Todd Zuercher
> > >
> > > Thanks.  I tried all that and now it's perfect for me.  It allows the
> > > fairly significant X axis backlash to be taken out without re-tripping
> > > the home/limit switch which was a bit of an issue. To get around it I
> > > reduced the backlash setting which caused its own set of problems.
> > > All good now.
> > >
> > > Now for the EDITOR setting.   I can load a G-Code file, select the
> > > menu entry to edit a file.  If it's the LCNC one loaded at start-up
> > > I'm told it's read only.  If it's one of mine, nothing happens.  No
> > > editor. Nothing.
> > >
> > > I've been using Mousepad outside of LCNC but setting Editor to
> > > Mousepad doesn�t work nor does setting it to the desktop link
> > > /usr/share/applications.   Unlike Windows, unfortunately the link
> > > doesn't actually specify where the executable is.
> > >
> > > So what can I do.  How do I specify the editor so that it runs with
> > > the currently loaded G-Code file?
> > >
> > > From the doc:
> > > EDITOR = gedit - The editor to use when selecting File > Edit to edit
> > > the G code from the AXIS menu. This must be configured for this menu
> > > item to work. Another valid entry is gnome-terminal -e vim.
> > >
> > First off, that gedit is an accidental code scrambler, evict it from the
> > facility. Give your machine a net cable, Then use synaptic to survey
> > what might be handy to go with geany.  It has a plethora of pluggins.
> >
> > And then edit that .ini file to say geany.  It has not made a mistake
> > that wasn't my own clumsy fat & ancient fingers in 4 or so years and its
> > never scrambled a big 800 loc .hal file yet.
> > >
> > >
> > >
> > >
> > >
> > > ___
> > > 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