[Emc-users] looking for advice on best wiring practices and grounding on cnc mills

[andrew beck]

Hey guys.

I have a bit of a story here and some questions..  I Have been seeing the
emails coming through and there looks like there is a massive pool of
knowledge here in the user list and the forum.  So here it goes hopefully
someone can help me.

I have a Big 6.5 ton VMC that I have been retrofitting with new chinese
servo drives and motors.  3 months ago I wired it up and after a bit of
mucking around I got the X and y axis moving fine.  (I am just using step
and direction with a mesa  5i25-7i76 combo for now)  Then I connected up
the Z axis motor and powered the 24v to the brake with a cheap powersupply
from aliexpress.

I was trouble shooting the limit switches and moving the wires while the
machine was live when there was a big bang and the limit switch arced
across into the steel cabinet.  It absolutely freaked me out and I haven't
been back to the mill since lol.

Once I recovered myself I realised that I have blown the Z axis servo drive
up.  What I think has happened is the powersupply was a floating
powersuppply(I actually knew that but didn't realise what that would
mean.)  That meant that the brake actually had a lot more than 24 volts in
it relative to machine earth(like 200v I am guessing, it was a big bang!)

Anyway I think somehow the power backfed via the Z axis servo down the 24
volt brake line and into the servo drive and made the magic smoke come out.

They are about $400 usd so I wasn't to happy about that.

But the good news is I told my supplier about it and he said they would
repair it for free.  they decided it was truely toast when they had a look,
so they just gave me a new drive.  which was pretty cool.

And after all that I am just getting into connecting this thing up again
and I don't want to blow anything up.

I will send a diagram later and some photos but for now I have these
questions.


   1. how do I ground the 24 volt switching powersupplies.
   2. Should I isolate the 24volt switching powersupplies from machine
   ground?  bearing in mind that one of the powersupplies is for logic power
   and one is just the the servo motor brake.
   3. The old wiring had a isolating transformer to make 240 V single phase
   for the switch powersupplies.  They didn't use a neutral back to the shed
   main board.  Will a neutral help me here?
   4. My biggest unknown is not knowing all the best safe practices when
   working with large voltages.  (my brother is a apprentice electrician which
   helps but I would appreciate some tips of what not to do and what to do as
   a checklist or something.

Regards

Andrew

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Re: [Emc-users] X Axis oil passages

[John Dammeyer]

> From: Andy Pugh [mailto:bodge...@gmail.com]
> > On 25 Dec 2019, at 17:22, John Dammeyer <  
> > jo...@autoartisans.com>
> wrote:
> >
> > Any suggestions on the type of plastic?
> 
> I would probably use Delrin. Easy to machine, and I have some.
 
Actually so do I.
 
Table is back on.  Tapered Gib adjusted and then locked with the screw on the 
opposite end.  I can just push it from one end to the other and there are no 
noticeable tight spots.  
 
For now I'll leave the overflowchannel until I'm ready to install the pump 
oiler.  First all the other little CNC conversion items need to be done but at 
least I now have measurements for the lead screw nut and I have to think about 
either making a new one that can be adjusted to remove the 0.023" or so worth 
of backlash or just go Ball Screws.  
Photo shows just how cheezy this is.

In either case, that's when I'll do the pump oiler and look clearly at how to 
lubricate the dovetails.
 
Thanks everyone.
Merry Christmas.
John
 
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Re: [Emc-users] X Axis oil passages

[Andy Pugh]

> On 25 Dec 2019, at 17:22, John Dammeyer  wrote:
> 
> Any suggestions on the type of plastic?

I would probably use Delrin. Easy to machine, and I have some.  


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Re: [Emc-users] X Axis oil passages

[Gene Heskett]

On Wednesday 25 December 2019 12:58:26 John Dammeyer wrote:

> Hi Gene,
>
> > At least it has SOME even if poorly done, John  My Grizzly G0704 has
> > zilch, nada, none. I've been in the Grizzly showroom several times,
> > and unless the quality bigger stuff has a one shot, I've seen zero
> > evidence of oilers, no flip cap cups, nada on any of them.
>
> They no longer make the G3616
> https://www.grizzly.com/search?q=(G3616)
> but this is the closest
> https://www.grizzly.com/products/Grizzly-9-x-39-2-HP-Horizontal-Vertic
>al-Mill-with-Power-Feed/G0757
>
> My table is shorter and I don't have the Horizontal Mill option and
> the spindle is only 2HP instead of 3HP.  Otherwise I can't see much
> difference.  The quality control is slightly worse than mine as the
> photo shows the end plate (pinned with tapered pins) isn't straight. 
> Mine isn't either but not as far off as this one.
>
> One has to wonder if the lead screw is even parallel to the table with
> that level of sloppy fitting.  It wold be easy enough to jig something
> to maintain the surface parallel and the holes.
>
> With CNC I don't know if a pivoting table and horizontal mill feature
> is needed anymore.  Perhaps someone with more CNC experience can chime
> in here.  With full CNC is a pivoting table like the one this mill has
> redundant?
>
> Thanks
> John

ISWYM This one's major flaws would likely be fixed by carefull reassembly 
as the cnc stuff was being installed. The rotating table makes gear 
cutting a bit easier but its a wash once cnc'd.

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] X Axis oil passages

[Gene Heskett]

On Wednesday 25 December 2019 12:22:53 John Dammeyer wrote:

> > From: Andy Pugh [mailto:bodge...@gmail.com]
> >
> > > On 25 Dec 2019, at 08:32, John Dammeyer <
> > >  jo...@autoartisans.com>
> >
> > wrote:
> > > But how do I block the slot so the oil doesn't fall off the edge.
> >
> > Maybe drill a hole normal to the surface and push in a peg. Maybe
> > plastic, possibly iron carefully blended.
>
> Any suggestions on the type of plastic?  Nylon maybe?
>
> Should the hole that connects to the dovetail be normal to the ways or
> the dovetail angle?  Anyone have a Bridgeport missing an X axis at the
> moment that they can check?

I would pay more attention to it intersecting the way surface as high, 
gravitywise, as possible so the oil's natural tendency to run downhill 
to distribute was exploited. A track in a zig-zag pattern on the wear 
surface would be a plus, but should be done to a surface that isn't open 
ended when the table is at the end of travel. So the zig-zag pattern is 
then in the fixed surface, not in the gib which travels with the table 
in most designs. We re not talking about a high degree of oil velocity 
negotiating a corner here.
>
> I do see how the dripping over the edge would put oil onto the moving
> side of the gib and on the other side, the dovetail edge.  But most of
> the oil tends to go there rather than the rest of the way to the blind
> end of the groove.
>
> The oiler videos often show there is a feed pipe at both ends.  Mine
> only has the feed fixture at the one end.   For some reason, there is
> a gib adjustment screw at both ends. 

That is more than likely a tapered gib, driving it one way or the other 
adjusts the clearance. They, in my G0704 work very well indeed.

> The LHS has the oiler ball 
> bearing plug which will be replaced with the single shot oiler pipe.
>
>
> While the RHS has nothing but this is where the actual gib screw sits.
>  Very odd.  I could put a feed pipe connection here too

Definitely. If the gib moves with the table, bring the feed in thru the 
casting face. If the gib doesn't move with the table, put a lengthwise 
slot in the gib so oil can get to the wear side and bring it thru the 
gib.

These thoughts are more rules of thumb than carved in stone.  Stuff in 
the way always wins.
>
> I've only had the Single Shot Oiler and tubing etc. for about 10
> years.  Project #42. John

I'm not even that close. I don't have the oilers yet. lol.

Merry Christmas John.

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] X Axis oil passages

[N]

> > From: Andy Pugh [mailto:bodge...@gmail.com]
> > > On 25 Dec 2019, at 08:32, John Dammeyer <  
> > > jo...@autoartisans.com>
> > wrote:
> > >
> > > But how do I block the slot so the oil doesn't fall off the edge.
> > 
> > Maybe drill a hole normal to the surface and push in a peg. Maybe plastic,
> > possibly iron carefully blended.
> > 
> Any suggestions on the type of plastic?  Nylon maybe?

For rubber I am pretty shure nitril is the right choice for plastic I have no 
idea though I am not certain all plastics like oil. Nylon which is a polyamide 
may absorb water which might not be a problem, pretty sure it will grow in size 
if this happens, remember hard to move lever for tractor hydraulics there  I 
used a file to enlarge hole a little bit.


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Re: [Emc-users] X Axis oil passages

[John Dammeyer]

Hi Gene,
 
> At least it has SOME even if poorly done, John  My Grizzly G0704 has
> zilch, nada, none. I've been in the Grizzly showroom several times, and
> unless the quality bigger stuff has a one shot, I've seen zero evidence
> of oilers, no flip cap cups, nada on any of them.
> 
 
They no longer make the G3616 
https://www.grizzly.com/search?q=(G3616)
but this is the closest
https://www.grizzly.com/products/Grizzly-9-x-39-2-HP-Horizontal-Vertical-Mill-with-Power-Feed/G0757
 
My table is shorter and I don't have the Horizontal Mill option and the spindle 
is only 2HP instead of 3HP.  Otherwise I can't see much difference.  The 
quality control is slightly worse than mine as the photo shows the end plate 
(pinned with tapered pins) isn't straight.  Mine isn't either but not as far 
off as this one. 

One has to wonder if the lead screw is even parallel to the table with that 
level of sloppy fitting.  It wold be easy enough to jig something to maintain 
the surface parallel and the holes.
 
With CNC I don't know if a pivoting table and horizontal mill feature is needed 
anymore.  Perhaps someone with more CNC experience can chime in here.  With 
full CNC is a pivoting table like the one this mill has redundant?
 
Thanks
John
 
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Re: [Emc-users] X Axis oil passages

[John Dammeyer]

> From: Andy Pugh [mailto:bodge...@gmail.com]
> > On 25 Dec 2019, at 08:32, John Dammeyer <  
> > jo...@autoartisans.com>
> wrote:
> >
> > But how do I block the slot so the oil doesn't fall off the edge.
> 
> Maybe drill a hole normal to the surface and push in a peg. Maybe plastic,
> possibly iron carefully blended.
> 
Any suggestions on the type of plastic?  Nylon maybe?
 
Should the hole that connects to the dovetail be normal to the ways or the 
dovetail angle?  Anyone have a Bridgeport missing an X axis at the moment that 
they can check?
 
I do see how the dripping over the edge would put oil onto the moving side of 
the gib and on the other side, the dovetail edge.  But most of the oil tends to 
go there rather than the rest of the way to the blind end of the groove.
 
The oiler videos often show there is a feed pipe at both ends.  Mine only has 
the feed fixture at the one end.   For some reason, there is a gib adjustment 
screw at both ends.  The LHS has the oiler ball bearing plug which will be 
replaced with the single shot oiler pipe.

 
While the RHS has nothing but this is where the actual gib screw sits.  Very 
odd.  I could put a feed pipe connection here too 

 
I've only had the Single Shot Oiler and tubing etc. for about 10 years.  
Project #42.
John
 
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Re: [Emc-users] X Axis oil passages

[Andy Pugh]

> On 25 Dec 2019, at 08:32, John Dammeyer  wrote:
> 
> But how do I block the slot so the oil doesn't fall off the edge.

Maybe drill a hole normal to the surface and push in a peg. Maybe plastic, 
possibly iron carefully blended. 

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Re: [Emc-users] X Axis oil passages

[Gene Heskett]

On Wednesday 25 December 2019 03:32:22 John Dammeyer wrote:

> Happy Christmas everyone.
>
> Having nothing better to do I took apart the X axis of my House of
> Tools (Cdn. company now gone) equivalent to the Grizzly Tools G3616
> mill.  Very disappointed to find that the oil channels are very poorly
> done.

At least it has SOME even if poorly done, John  My Grizzly G0704 has 
zilch, nada, none. I've been in the Grizzly showroom several times, and 
unless the quality bigger stuff has a one shot, I've seen zero evidence 
of oilers, no flip cap cups, nada on any of them.

> After watching lots of youtube videos it's clear that the channels
> should have been carved at an angle across the ways rather than
> straight so that the oil would more easily spread across the surface.
>
> Also it seems the good Bridgeports have a hole to bleed the oil down
> to the tapered gib and the gib itself has a hole and a channel to
> spread the oil on both sides of the gib so that the moving surface is
> lubricated.
>
> The builders of this mill thought the waterfall effect would be good
> enough and certainly the pool of oil under the dribble slot shows
> there was a waterfall.
>
> I don't have an issue with drilling a hole through the tapered gib nor
> grinding a small slot along both sides.  I can even see drilling a
> hole in the waterfall slot at the middle point there so that I have a
> hole that would match up with the tapered gib.  On the non-gib side
> just a hole I guess.
>
> But how do I block the slot so the oil doesn't fall off the edge. 
> Looking at the oil channel it's clear that not much reaches the near
> end.  Probably because it takes the easiest exit off the side.  The
> oil injection point is at the far end in the photo.  (Mill LH Side).
>
> Just use epoxy?  Can't really braze it closed.  Maybe for a manual
> mill the lack of lubrication isn't an issue but for CNC running 150ipm
>  (3810mm/min) lubrication is kind of important.
>
I'd clean it up, then clean up the ends that ought to be blocked even 
better, and add a drop of JB Weld, let it set to block the exit and then 
shave it flush.  And drill for oil cups and install wicking. I've 
thought on it some and it looks like the only sensible place on the 
GO704 is the bottom of the T slot, dead center lengthwise. Angling 
outward to hit the gib, cutting a lengthwise zig-zag pattern in the 
tapered gib to complete the distribution system.

The present system is wipe it as clean as I can with solvent soaked 
cotton balls and then soak one in vactra and re-wet it. About every 2 
weeks when its busy. Squirt some into the top of the post/gib joints 
about weekly. Someday buy an oiler. Someday.  And figure out how to get 
it to the y slider. All 3 nuts wouldn't hurt, lots of weed eater fuel 
line though, I could easily see a 50 dollar bills worth of that at a 
buck 50 a foot by the time you've hit it all.
>
> Thanks for any suggestions.
> John

This is a problem, unless its designed in, retrofitting this is a PIMA. 
But I've no better ideas either. I did have oil lines to the ball nuts 
in the now failed HF conversion, and that worked well from a snap cap on 
the post.

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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[Emc-users] X Axis oil passages

[John Dammeyer]

Happy Christmas everyone.
 
Having nothing better to do I took apart the X axis of my House of Tools (Cdn. 
company now gone) equivalent to the Grizzly Tools G3616 mill.  Very 
disappointed to find that the oil channels are very poorly done.  
 
After watching lots of youtube videos it's clear that the channels should have 
been carved at an angle across the ways rather than straight so that the oil 
would more easily spread across the surface.
 
Also it seems the good Bridgeports have a hole to bleed the oil down to the 
tapered gib and the gib itself has a hole and a channel to spread the oil on 
both sides of the gib so that the moving surface is lubricated.
 
The builders of this mill thought the waterfall effect would be good enough and 
certainly the pool of oil under the dribble slot shows there was a waterfall.
 
I don't have an issue with drilling a hole through the tapered gib nor grinding 
a small slot along both sides.  I can even see drilling a hole in the waterfall 
slot at the middle point there so that I have a hole that would match up with 
the tapered gib.  On the non-gib side just a hole I guess.
 
But how do I block the slot so the oil doesn't fall off the edge.  Looking at 
the oil channel it's clear that not much reaches the near end.  Probably 
because it takes the easiest exit off the side.  The oil injection point is at 
the far end in the photo.  (Mill LH Side).
 
Just use epoxy?  Can't really braze it closed.  Maybe for a manual mill the 
lack of lubrication isn't an issue but for CNC running 150ipm  (3810mm/min) 
lubrication is kind of important.
 

Thanks for any suggestions.
John
 
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