Re: [Emc-users] Rigid tapping with geared encoder

[Chris Radek]

Your intuition is right.  If you don't care about starting in the
same orientation each time, it doesn't matter.  

My VMC has the encoder on the motor, and it doesn't have an index at
all.  I wired the A to the Z input on the mesa card so it gets lots
of indexes and the tapping starts wherever it happens to be.

My lathes of course have real index.

On Fri, Sep 03, 2021 at 04:29:55PM +0100, andy pugh wrote:
> I have just advised someone on the forum that he needs a 1ppr index to
> rigid tap, as his encoder is mounted to the motor, not to the spindle.
> 
> But then I started wondering if this is technically correct. I have a
> feeling that single=pass rigid tapping will be fine, but mutli-pass
> won't work?
> 
> Has anyone tried this?


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[Emc-users] Rigid tapping with geared encoder

[Henk du preez]

It works. We are doing it on a deckel FP5

Rigid tapping but only one pass. There is no way of knowing which index
pulse will be detected since there are more than one depending on which
gear you are in.

Spindle-position is scaled by the exact gear ratio you are in at any given
time.

On another machine, I built a quad encoder using proximity switches. Only
24 PPR direct on the spindle. Wired to one of the encoder inputs via a line
driver IC, this is good up to 500 rpm and I have rigid tapped multiple M3 x
0.5 holes.

Henk

On Fri, 03 Sep 2021, 18:37 , 
wrote:

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> Today's Topics:
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>1. Rigid tapping with geared encoder (andy pugh)
>2. Re: Rigid tapping with geared encoder (Leonardo Marsaglia)
>3. Re: Rigid tapping with geared encoder (Rene Hopf)
>4. Re: Rigid tapping with geared encoder (John Dammeyer)
>5. Re: Rigid tapping with geared encoder (Gene Heskett)
>
>
> --
>
> Message: 1
> Date: Fri, 3 Sep 2021 16:29:55 +0100
> From: andy pugh 
> To: "Enhanced Machine Controller (EMC)"
> 
> Subject: [Emc-users] Rigid tapping with geared encoder
> Message-ID:
> <
> can1+yzxwooxwaluwmmuhx3phdn8rygrbc-r651j5xz-eh9d...@mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> I have just advised someone on the forum that he needs a 1ppr index to
> rigid tap, as his encoder is mounted to the motor, not to the spindle.
>
> But then I started wondering if this is technically correct. I have a
> feeling that single=pass rigid tapping will be fine, but mutli-pass
> won't work?
>
> Has anyone tried this?
>
> --
> 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, 1912
>
>
>
> ------
>
> Message: 2
> Date: Fri, 3 Sep 2021 13:11:10 -0300
> From: Leonardo Marsaglia 
> To: "Enhanced Machine Controller (EMC)"
> 
> Subject: Re: [Emc-users] Rigid tapping with geared encoder
> Message-ID:
>  544uaxz4grzep-rg...@mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Hello Andy,
>
> Didn't try rigid tapping but the Mazak has the encoder coupled to the
> spindle by means of a timing belt in a 1:1 ratio. So, unless the motor in
> that machine is coupled in a synchronized way to the spindle you'll always
> have the chance of missing synchronization. Also ,as you pointed out, if
> the ratio is not exactly 1:1 you'll eventually have deviation as the
> spindle turns (assuming this is a 1 PPR configuration).
>
> El vie, 3 sept 2021 a las 12:35, andy pugh ()
> escribi?:
>
> > I have just advised someone on the forum that he needs a 1ppr index to
> > rigid tap, as his encoder is mounted to the motor, not to the spindle.
> >
> > But then I started wondering if this is technically correct. I have a
> > feeling that single=pass rigid tapping will be fine, but mutli-pass
> > won't work?
> >
> > Has anyone tried this?
> >
> > --
> > 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, 1912
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
>
> --
>
> Message: 3
> Date: Fri, 3 Sep 2021 18:12:21 +0200
> From: Rene Hopf 
> To: "Enhanced Machine Controller (EMC)"
> 
> Subject: Re: [Emc-users] Rigid tapping with geared encoder
> Message-ID: 
> Content-Type: text/plain; charset=utf-8
>
>
>
> > On 3. Sep 2021, at 17:32, andy pugh  wrote:
> >
> > ?I have just advised someone on the forum that he needs a 1ppr index to
> > rigid tap, as his encoder is mounted to the moto

Re: [Emc-users] Rigid tapping with geared encoder

[Gene Heskett]

On Friday 03 September 2021 11:29:55 andy pugh wrote:

> I have just advised someone on the forum that he needs a 1ppr index to
> rigid tap, as his encoder is mounted to the motor, not to the spindle.
>
> But then I started wondering if this is technically correct. I have a
> feeling that single=pass rigid tapping will be fine, but mutli-pass
> won't work?
>
> Has anyone tried this?

I am doing it on the G0704, encoder is on the spindle motor but I do use 
multipass for threading on 1/4" and bigger taps, so my index IS from the 
spindle. This does result in some huge scale settings, wnich I switch with a 
gear shift tally switches but that doesn't seem to bother LinuxCNC.

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] Rigid tapping with geared encoder

[John Dammeyer]

Andy,
As I recall when it was explained to me is that the index pulse is used once to 
start the process.  After that the quadrature encoder A/B signals let the 
trajectory planner know how fast it's going and in which direction.  I'm not 
sure if it even requires the index for multipass.

But then it may also have you that explained it to me...
John




> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: September-03-21 8:30 AM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] Rigid tapping with geared encoder
> 
> I have just advised someone on the forum that he needs a 1ppr index to
> rigid tap, as his encoder is mounted to the motor, not to the spindle.
> 
> But then I started wondering if this is technically correct. I have a
> feeling that single=pass rigid tapping will be fine, but mutli-pass
> won't work?
> 
> Has anyone tried this?
> 
> --
> 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, 1912
> 
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users



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Re: [Emc-users] Rigid tapping with geared encoder

[Leonardo Marsaglia]

Hello Andy,

Didn't try rigid tapping but the Mazak has the encoder coupled to the
spindle by means of a timing belt in a 1:1 ratio. So, unless the motor in
that machine is coupled in a synchronized way to the spindle you'll always
have the chance of missing synchronization. Also ,as you pointed out, if
the ratio is not exactly 1:1 you'll eventually have deviation as the
spindle turns (assuming this is a 1 PPR configuration).

El vie, 3 sept 2021 a las 12:35, andy pugh () escribió:

> I have just advised someone on the forum that he needs a 1ppr index to
> rigid tap, as his encoder is mounted to the motor, not to the spindle.
>
> But then I started wondering if this is technically correct. I have a
> feeling that single=pass rigid tapping will be fine, but mutli-pass
> won't work?
>
> Has anyone tried this?
>
> --
> 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, 1912
>
>
> ___
> Emc-users mailing list
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Re: [Emc-users] Rigid tapping with geared encoder

[Rene Hopf via Emc-users]

> On 3. Sep 2021, at 17:32, andy pugh  wrote:
> 
> I have just advised someone on the forum that he needs a 1ppr index to
> rigid tap, as his encoder is mounted to the motor, not to the spindle.
> 
> But then I started wondering if this is technically correct. I have a
> feeling that single=pass rigid tapping will be fine, but mutli-pass
> won't work?

On my haas the encoder is geared 1:2, the index is only seen on every second 
rotation. No issues. It only takes longer for the engagement move.

> 
> Has anyone tried this?
> 
> -- 
> 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, 1912
> 
> 
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[Emc-users] Rigid tapping with geared encoder

[andy pugh]

I have just advised someone on the forum that he needs a 1ppr index to
rigid tap, as his encoder is mounted to the motor, not to the spindle.

But then I started wondering if this is technically correct. I have a
feeling that single=pass rigid tapping will be fine, but mutli-pass
won't work?

Has anyone tried this?

-- 
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, 1912


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