Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Stuart Stevenson 
Plus or minus .010 is an amazing amount. Also, you mentioned another area
on the screw you saw .001 lost motion. This leads to a screw problem.
I would do what Jon Elson says as this sounds strange but I would expect to
find screw wear. If it was nut wear the backlash in all areas of the screw
would be close to equal. Not knowing the drive train maybe there is a gear
train and one area of the gear train has worn teeth and where you found
almost no lost motion is where the gear train is the best.
Expect screw wear but hope for a gear train problem.
HTH
Stuart

On Mon, Apr 12, 2021 at 5:15 PM Jon Elson  wrote:

> On 04/12/2021 09:48 AM, Todd Zuercher wrote:
> > Those here who have had to deal with a worn out ball screw.
> I'd dig into the works and examine everything.  It does NOT
> sound like simple wear.
> The rotating nut likely runs in a pair of either
> angular-contact bearings or tapered roller
> bearings.  There will be a preloading arrangement to
> constrain the nut.  Also, the
> screw is usually fixed at both ends.  If the clamp has
> gotten loose at one or both ends, it could
> allow some flex of the mount under load.  Attach a dial test
> indicator to the slide and
> read against the end of the screw, and watch for movement
> when you apply load.
>
> Some old ballnuts were actually TWO completely separate nuts
> that were preloaded against
> each other with Belleville washers.  It is possible some of
> the Bellevilles have cracked.
> Also, they often used dowel pins to align the two nuts
> rotationally.  If one of the dowels has
> cracked, that could cause this kind of issue.
>
> Jon
>
>
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Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Jon Elson 

On 04/12/2021 09:48 AM, Todd Zuercher wrote:

Those here who have had to deal with a worn out ball screw.
I'd dig into the works and examine everything.  It does NOT 
sound like simple wear.
The rotating nut likely runs in a pair of either 
angular-contact bearings or tapered roller
bearings.  There will be a preloading arrangement to 
constrain the nut.  Also, the
screw is usually fixed at both ends.  If the clamp has 
gotten loose at one or both ends, it could
allow some flex of the mount under load.  Attach a dial test 
indicator to the slide and
read against the end of the screw, and watch for movement 
when you apply load.


Some old ballnuts were actually TWO completely separate nuts 
that were preloaded against
each other with Belleville washers.  It is possible some of 
the Bellevilles have cracked.
Also, they often used dowel pins to align the two nuts 
rotationally.  If one of the dowels has

cracked, that could cause this kind of issue.

Jon


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Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Thaddeus Waldner 
It would technically still have thrust bearings, no? But on the nut instead of 
on the screw. I’m not sure this changes anything.

> On Apr 12, 2021, at 3:55 PM, Gene Heskett  wrote:
> 
> On Monday 12 April 2021 14:55:18 Ralph Stirling wrote:
> 
>> Thrust bearings at the ball screw ends perhaps?
>> 
> You may want to read it again Ralph, the screw is fixed, with a rotating 
> nut.
> 
> I had one like that I built once. I think Todd is correct and the screw 
> needs to go to a rebuilder. With the nut still on it because they may 
> have to work on both. My $0.02 of coarse.
>> -- Ralph
>> 
>> From: Todd Zuercher [to...@pgrahamdunn.com]
>> Sent: Monday, April 12, 2021 7:48 AM
>> To: Enhanced Machine Controller (EMC)
>> Subject: [Emc-users] Worn Ball Screw?
>> 
>> CAUTION: This email originated from outside the Walla Walla University
>> email system.
>> 
>> 
>> Those here who have had to deal with a worn out ball screw.  How is
>> this normally manifested.  I have a machine that is only showing
>> backlash under load.  Is that normally how a worn out screw shows it's
>> age?  I was expecting it to be normal loose backlash that you can
>> measure.  But this is showing up as springy softness that you have to
>> give a pretty hard shove against to move the dial indicator, then it
>> snaps back to zero when you let go.  Using the usual jogging methods
>> to read backlash, the machine reads zero backlash and positions well. 
>> But dynamically it is awful, with loud clucking noises on direction
>> changes and horribly wavy marks left on the pieces milled at those
>> changes.  Giving a shove on the table, I can measure more than
>> +/-0.01" of this  "springy" backlash, but moving the screw to a
>> normally unused position I can only measure about 0.001".  This is a
>> big fixed screw (about 2" diameter and more than 14ft long) with
>> rotating nut, is there any hope of fixing it?  I'm considering trying
>> to send the screw out to one of those screw refurbishing places.  The
>> machine manufacturer quoted us over $18,000 to replace it.
>> 
>> Todd Zuercher
>> P. Graham Dunn
>> Inc.> www.pgrahamdunn.com%2Findex.phpdata=04%7C01%7Cralph.stirling%40wal
>> lawalla.edu%7C58338609df8b45b6914308d8fde00b00%7Cd958f048e43142779c8deb
>> fb75e7aa64%7C0%7C0%7C637538485997249904%7CUnknown%7CTWFpbGZsb3d8eyJWIjo
>> iMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000
>> sdata=Ld9xm92SAMAjLkMiiIF8IUVaEr%2FNPwfF0CkiXtceb3E%3Dreserved=0>
>> 630 Henry Street
>> Dalton, Ohio 44618
>> Phone:  (330)828-2105ext. 2031
>> 
>> 
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>> 048e43142779c8debfb75e7aa64%7C0%7C0%7C637538485997249904%7CUnknown%7CTW
>> FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6M
>> n0%3D%7C1000sdata=IkA489PPWpVFBGtsJze2eyUhLWfAKYR3Lw2k0frRhLc%3D
>> mp;reserved=0
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> 
> 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] Worn Ball Screw?

2021-04-12 Thread andy pugh 
On Mon, 12 Apr 2021 at 21:57, Gene Heskett  wrote:
>
> On Monday 12 April 2021 14:55:18 Ralph Stirling wrote:
>
> > Thrust bearings at the ball screw ends perhaps?

> You may want to read it again Ralph, the screw is fixed, with a rotating
> nut.

The nut rotates in bearings, however.

Personally I have not had anything wear out yet, so can't say.

-- 
atp
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designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Gene Heskett 
On Monday 12 April 2021 14:55:18 Ralph Stirling wrote:

> Thrust bearings at the ball screw ends perhaps?
>
You may want to read it again Ralph, the screw is fixed, with a rotating 
nut.

I had one like that I built once. I think Todd is correct and the screw 
needs to go to a rebuilder. With the nut still on it because they may 
have to work on both. My $0.02 of coarse.
> -- Ralph
> 
> From: Todd Zuercher [to...@pgrahamdunn.com]
> Sent: Monday, April 12, 2021 7:48 AM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] Worn Ball Screw?
>
> CAUTION: This email originated from outside the Walla Walla University
> email system.
>
>
> Those here who have had to deal with a worn out ball screw.  How is
> this normally manifested.  I have a machine that is only showing
> backlash under load.  Is that normally how a worn out screw shows it's
> age?  I was expecting it to be normal loose backlash that you can
> measure.  But this is showing up as springy softness that you have to
> give a pretty hard shove against to move the dial indicator, then it
> snaps back to zero when you let go.  Using the usual jogging methods
> to read backlash, the machine reads zero backlash and positions well. 
> But dynamically it is awful, with loud clucking noises on direction
> changes and horribly wavy marks left on the pieces milled at those
> changes.  Giving a shove on the table, I can measure more than
> +/-0.01" of this  "springy" backlash, but moving the screw to a
> normally unused position I can only measure about 0.001".  This is a
> big fixed screw (about 2" diameter and more than 14ft long) with
> rotating nut, is there any hope of fixing it?  I'm considering trying
> to send the screw out to one of those screw refurbishing places.  The
> machine manufacturer quoted us over $18,000 to replace it.
>
> Todd Zuercher
> P. Graham Dunn
> Inc.www.pgrahamdunn.com%2Findex.phpdata=04%7C01%7Cralph.stirling%40wal
>lawalla.edu%7C58338609df8b45b6914308d8fde00b00%7Cd958f048e43142779c8deb
>fb75e7aa64%7C0%7C0%7C637538485997249904%7CUnknown%7CTWFpbGZsb3d8eyJWIjo
>iMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000
>sdata=Ld9xm92SAMAjLkMiiIF8IUVaEr%2FNPwfF0CkiXtceb3E%3Dreserved=0>
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
>
>
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>048e43142779c8debfb75e7aa64%7C0%7C0%7C637538485997249904%7CUnknown%7CTW
>FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6M
>n0%3D%7C1000sdata=IkA489PPWpVFBGtsJze2eyUhLWfAKYR3Lw2k0frRhLc%3D
>mp;reserved=0
>
>
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Cheers, Gene Heskett
-- 
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 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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 - Louis D. Brandeis
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Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Leonardo Marsaglia 
Could this be a worn thrust bearing instead? I had a similar behavior a few
years ago and that was the cause.

Leonardo Marsaglia

El lun., 12 abr. 2021 15:25, Todd Zuercher  escribió:

> Those here who have had to deal with a worn out ball screw.  How is this
> normally manifested.  I have a machine that is only showing backlash under
> load.  Is that normally how a worn out screw shows it's age?  I was
> expecting it to be normal loose backlash that you can measure.  But this is
> showing up as springy softness that you have to give a pretty hard shove
> against to move the dial indicator, then it snaps back to zero when you let
> go.  Using the usual jogging methods to read backlash, the machine reads
> zero backlash and positions well.  But dynamically it is awful, with loud
> clucking noises on direction changes and horribly wavy marks left on the
> pieces milled at those changes.  Giving a shove on the table, I can measure
> more than +/-0.01" of this  "springy" backlash, but moving the screw to a
> normally unused position I can only measure about 0.001".  This is a big
> fixed screw (about 2" diameter and more than 14ft long) with rotating nut,
> is there any hope of fixing it?  I'm considering trying to send the screw
> out to one of those screw refurbishing places.  The machine manufacturer
> quoted us over $18,000 to replace it.
>
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
>
>
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Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Ralph Stirling 
Thrust bearings at the ball screw ends perhaps?

-- Ralph

From: Todd Zuercher [to...@pgrahamdunn.com]
Sent: Monday, April 12, 2021 7:48 AM
To: Enhanced Machine Controller (EMC)
Subject: [Emc-users] Worn Ball Screw?

CAUTION: This email originated from outside the Walla Walla University email 
system.


Those here who have had to deal with a worn out ball screw.  How is this 
normally manifested.  I have a machine that is only showing backlash under 
load.  Is that normally how a worn out screw shows it's age?  I was expecting 
it to be normal loose backlash that you can measure.  But this is showing up as 
springy softness that you have to give a pretty hard shove against to move the 
dial indicator, then it snaps back to zero when you let go.  Using the usual 
jogging methods to read backlash, the machine reads zero backlash and positions 
well.  But dynamically it is awful, with loud clucking noises on direction 
changes and horribly wavy marks left on the pieces milled at those changes.  
Giving a shove on the table, I can measure more than +/-0.01" of this  
"springy" backlash, but moving the screw to a normally unused position I can 
only measure about 0.001".  This is a big fixed screw (about 2" diameter and 
more than 14ft long) with rotating nut, is there any hope of fixing it?  I'm 
considering trying to send the screw out to one of those screw refurbishing 
places.  The machine manufacturer quoted us over $18,000 to replace it.

Todd Zuercher
P. Graham Dunn 
Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031


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Re: [Emc-users] Worn Ball Screw?

2021-04-12 Thread Ed 

On 4/12/21 9:48 AM, Todd Zuercher wrote:

Those here who have had to deal with a worn out ball screw.  How is this normally manifested.  I have a 
machine that is only showing backlash under load.  Is that normally how a worn out screw shows it's age? 
 I was expecting it to be normal loose backlash that you can measure.  But this is showing up as springy 
softness that you have to give a pretty hard shove against to move the dial indicator, then it snaps 
back to zero when you let go.  Using the usual jogging methods to read backlash, the machine reads zero 
backlash and positions well.  But dynamically it is awful, with loud clucking noises on direction 
changes and horribly wavy marks left on the pieces milled at those changes.  Giving a shove on the 
table, I can measure more than +/-0.01" of this  "springy" backlash, but moving the screw 
to a normally unused position I can only measure about 0.001".  This is a big fixed screw (about 
2" diameter and more than 14ft long) with rotating nut, is there any hope of fixing it?  I'm co
  nsidering trying to send the screw out to one of those screw refurbishing 
places.  The machine manufacturer quoted us over $18,000 to replace it.

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031


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Normally a ballscrew is not "springy or spongy" anyplace. Usually the 
balls wear more than the screw or nut. Reballing a nut is not hard or 
expensive.


Does this have an external ball track?

Is the backlash more in one place than another?


Ed.





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[Emc-users] Worn Ball Screw?

2021-04-12 Thread Todd Zuercher 
Those here who have had to deal with a worn out ball screw.  How is this 
normally manifested.  I have a machine that is only showing backlash under 
load.  Is that normally how a worn out screw shows it's age?  I was expecting 
it to be normal loose backlash that you can measure.  But this is showing up as 
springy softness that you have to give a pretty hard shove against to move the 
dial indicator, then it snaps back to zero when you let go.  Using the usual 
jogging methods to read backlash, the machine reads zero backlash and positions 
well.  But dynamically it is awful, with loud clucking noises on direction 
changes and horribly wavy marks left on the pieces milled at those changes.  
Giving a shove on the table, I can measure more than +/-0.01" of this  
"springy" backlash, but moving the screw to a normally unused position I can 
only measure about 0.001".  This is a big fixed screw (about 2" diameter and 
more than 14ft long) with rotating nut, is there any hope of fixing it?  I'm 
considering trying to send the screw out to one of those screw refurbishing 
places.  The machine manufacturer quoted us over $18,000 to replace it.

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031


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Re: [Emc-users] 6 ton chevalier cnc first moves for those that are interested

2021-04-12 Thread John Dammeyer 
Nicely done.  Makes mine look slow at only 4500mm/min.   
Are your motors direct drive to the ball screws?  What torque/rpm are the 
motors rated at?
John


> -Original Message-
> From: andrew beck [mailto:andrewbeck0...@gmail.com]
> Sent: April-12-21 5:36 AM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] 6 ton chevalier cnc first moves for those that are 
> interested
> 
> hey guys just a video showing my new cnc retrofit
> 
> cheers
> 
> https://youtu.be/B42f9uG8Jmg
> 
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[Emc-users] 6 ton chevalier cnc first moves for those that are interested

2021-04-12 Thread andrew beck 
hey guys just a video showing my new cnc retrofit

cheers

https://youtu.be/B42f9uG8Jmg

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