[alexandrud21]

Hi Viteq.
Of course I contact yesterday. Every body recomend him but about the costmer suport hi is bad. I don't think hi will replace anythig. I ask him one question but hi reply another. Just take and look on the email.
Dear anyshka_23,

Dear Alex,
Our ballscrew is C7 class. And this is Rolled one.
We don't have Ground ballscrew with C3 class or better. As you know know the Ground ballscrew is much much higher in price.
Thank you in advance for your understanding.
Chai


- linearmotionbearings2008 Click "respond" to reply through Messages, or go to your email to reply






--------------------------------------------------------------------------------
From: anyshka_23
To: linearmotionbearings2008
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
Sent Date: 2010-07-16 03??24?37?





Dear linearmotionbearings2008,



Yes I belive this need to be. And maybe is but I told you my problem They are not 1605 this means one of my ballscrew have pich 4.985 and another have pich 4.995.
If you want replace me just one dosn't meater wich, but to be with the same pich.
I going to use on the same axis on cnc and I need to be identical pich.
If you going to help me to fix this problem please do. If you didn't want pleace tell me from start. I buyed from you because everyboby on cnczone and another forums recomend you, but from wath I see right now this is one of the big fals.
Thank you for understanding.
Alex

--- On Thu, 7/15/10, eBay ??: linearmotionbearings2008 <[email protected]> wrote:


From: eBay ??: linearmotionbearings2008 <[email protected]>
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
To: [email protected]
Date: Thursday, July 15, 2010, 9:58 PM




Dear anyshka_23,

Hello,
The ballscrew assembly (Ballnut and Spindle assembled) Precision rolled, class 7 accuracy; JIS (0.050/300mm) (0.002"/12")
Ballnut: Single ballnut with zero backlash (<0.015mm) (0.0006")
Thanks!
Chai


- linearmotionbearings2008




--------------------------------------------------------------------------------
From: anyshka_23
To: linearmotionbearings2008
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
Sent Date: 2010-07-16 01??15?10?





Dear linearmotionbearings2008,



Thanks for reply chai.
I belive they can reach C5 but my not get C7.
The problem is onother. They are not the same and I can't get the result that I want. If you going to pay shiping back I can send to you back. If is not resonable to you send me just the screw and video how to replase the nut. I don't know?
I tried to ajust from software but I can not. I wiil post the reply from software company.

Hi Alex,

I am afraid that you are not going to like my answer - you cannot have a slave axis with a different ratio than the master, they both need the same steps per... =/

Thanks,

scott
--
Scott Nichols
License Manager
www.machsupport.com

----- Original Message -----
From: alex djamalutdinov
To: [email protected]
Sent: Thursday, July 15, 2010 9:30 AM
Subject: Please help.


Hello.
This is Alex
I have licence "XXX"
I need some help because i did;n find on the forum and Yahoo.
My problem is next.
On the X axis I have slave the A axis. I discovery last nigth my bollsrew are not the same.
One have pich 4.995 mm and other have 4.985 mm. I tryed to change the the unit per mm but they allweys read the master axis.
Is some way to solve this problem.
Thank you.
Alexandru.
Georgia Atlanta
404-447-4241

How we can fix this problem?
O do not have another way. They are need to be replace.
Thank you again for understanding.
Alex
--- On Thu, 7/15/10, eBay ??: linearmotionbearings2008 <[email protected]> wrote:


From: eBay ??: linearmotionbearings2008 <[email protected]>
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
To: [email protected]
Date: Thursday, July 15, 2010, 7:12 PM




Dear anyshka_23,

Dear Alex,
Our screws are from Taiwan, world famous TBI brand. The website:
www.ballscrew.com.tw
I said it C7 class. In fact, that can reach C5 class.
Thanks!
Chai


- linearmotionbearings2008




--------------------------------------------------------------------------------
From: anyshka_23
To: linearmotionbearings2008
Subject: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
Sent Date: 2010-07-15 22??16?40?


Dear linearmotionbearings2008,

Hello Chai.
This is Alex.
I bouth for yor you 3 ballscrew and one spindle this year. The ballscrew was 1605 and have aprox 1 - 1820mm and 2 - 1860mm . I ansambled my cnc last week and I discovery one ballscrew have pich 5 mm, another have 4.995mm and another hava 4.985 mm. This means when I turn 200 rotation the gantry is move:
1 ballscrew 997mm
2 ballcrew 999mm
3 ballcrew 1000mm
All 3 ballscrew are for X and for Y axis.
The biguest problem is the first and second ballcrew are slaved(they need to turm in the same time), and I can get acuratci result. If they was both the same 4.995 or 4.985 was no problem, but in this case I can not ajust from the software.
I think this result is not C7. Anyway haw we can fix this problem? I need 2 identical ballscrew.
I leave in USA, GA, Norcross, 30092
Thank you for understanding.
Alex.


- anyshka_23

[alexandrud21]

Read email from the bottom up.
Thank you.

[veteq]

ooh man, i`m feeling sorry for you, think you have a problem that cant be solved....

the problem is the screw, not the nut.
it is not precise...

good luck

[Kipper]

ooh man, i`m feeling sorry for you, think you have a problem that cant be solved....

the problem is the screw, not the nut.
it is not precise...

good luck

Me too!

[SSN Vet]

China = (Hit / miss) x no recourse + no accountability + shipping expense

sounds like you rolled craps on this transaction

[wildwestpat]

Hi Alex

Undestand your frustration but ballscrews have three sources of positional error of which pitch error and positional error are some times confused. The other source of error is due to flex in the mounting or in the screw. BUT it looks as if you are on track to end up with a good machine. Here are thought on your screws.

The makers of lead screws specify the cumulative error over a stated distance C7 for example relates to +/- 0.007 " over 12". This indicates that your screws are probably Ok tolerance wise. Whilst you could get screws with matched leads these are expensive and are out of the question for most DIY CNC builds.

From your post would I be correct in assuming you have a gantry and that you are concerned about the possible error of one side with respect to the other? If this is so then I suggest you might consider setting the gantry to zero at the mid point of the axis travel. This will reduce the cumulative error at the end of travel. You could also calibrate the mid gantry possition to end of axis using Mach3 calibration proceedure which will improve the true possitional error. However you are now in the realms of measuring to better than 0.001" over 40".

To get better accuracy you need to up to quality to ground precision screws and a matched lead pair with glass scales and associated servos.

Sorry but in my opinion two of your screws are well with in spec and the third is possibly on the limit of acceptability for a C7. However you need to be pretty sophisticated to measure the errors in travel on large axis as the error in measurement has to be factored into the calculation.

Hope this helps - Pat

[veteq]

Hee Pat,

nice write up, didn`t know that info.
Could you tell a bit more... Is it common for rolled ballscrews that there is a lead deviation? 3mm is a lot (maybe this is really one screwed one...)
Would the hiwin rolled ones have the same problems?

Roy

[ihavenofish]

c7 grade should be .0018" per foot lead deviation although its not a universal standard. this is NOT cumulative error but rather the max deviation from the mean in any given foot. 0.007 per foot would be extremely bad and basically useless in an anti backlash ball screw, youd crush the balls somewhere along the travel.

the previous post seems to be complaining about a difference in lead from one srcew to the other of .01mm, which results in a difference from screw to screw of .035" per foot. the screws may have a lead deviation well within the c7 spec, but they arent matched which is where the problem lies. the grade of the screw doesnt represent this error.

mach should be able to account for this though as you can compensate for both steps per inch and lead deviation. having a slaved axis *shouldnt* interfere with these functions but i guess it seems to be.

i dont think the seller is at fault, and the screws are fine. i think the buyer just has an aplication where someone needs to take the effort to measure lead on the sellers side. its unreasonable to expect that service for free let alone automatic i think. i dont know if this seller has a reliable way of checking this.

[wildwestpat]

Hi Roy

The process of making the screw leads to minute variations in pitch between adjacent turns and variations accumulate along a length of the screw. I donot have access to the ANSI standard B5.48 - 1977 which defines the C7 tolerances. However most manufacturers state their tolerances in tems of error + or - over a given length usually 12" or 300mm. Since the tolerances is specified about the notional perfect screw the build up can be quite large over a 1.8 meters. (With a tolerance of 0.007 inch per foot this will be arround +/- 1.07 mm. Thus one leg could be on the plus limit and the other on the negtive limit.

Mach3 has the ability to compensate for the error in sending code to the motors and this is covered in the Mach3 manual very well the only problem is measuring the travel accurately. The minute turn to turn errors in pitch could be mapped but this is not a DIY home shop exercise as the screw has to be measured to a very high degree of precision. The movement of the screw and frame work will in all probability far exceed the error in pitch turn to turn - use glass scales or other optical length gauges with a closed loop servo on the axis at a ten fold increase in cost.

Follow the calibration using the mid axis zero and you minimise the errors.

Regards - Pat

[cyclestart]

There are lies, damn lies, and specifications
-----apologies to Mark Twain

2 have 4.985 on the X this means when I turn 200 turns gantry move 997mm

3 mm on a meter averages to .036" in a foot. Ouch ! (It's also very close to mistaking a metric screw for 5 tpi). Without knowing how the measurement was done it's hard to say if this all came down to the screw itself. If the screw does not deviate outside +/- spec deviation/foot it can still claim C7 no matter how badly it deviates from the nominal TPI ? At least that's what I think I'm reading ?? Something buyers should be aware of when slaving an axis. On a single screw axis we can compensate in steps/inch.

edit/ On rereading I see he's talking about a difference between 2 screws and not the deviation from the nominal pitch.

[ihavenofish]

If the screw does not deviate outside +/- spec deviation/foot it can still claim C7 no matter how badly it deviates from the nominal TPI ?

with rolled screws, they seem to only include deviation from the mean in the accuracy spec. so with c7 this is .0018". with ground screws they will often include the deviation from the specified pitch but its not standard aparently so 2 makers c5 ground scrws might have wildly different acumulated pitch error alowances, whcih the deviation from the mean might be the same.

so generally, the "grade" defines acuracy within the screw, and not relative to theoretical pitch. so you can have screws with pitches from 4.9mm to 5.1mm and still call them c7 as long as they are consistent to the overall pitch at less than .0018" per foot. 4.9 would be a crazy bad example of course.

matching screws it like matching linear rails. if you dont buy linear rails in matched sets, they may be different in height by as much as .015" for "standard" grade.

usually they use a notation like:

e(300) - deviation from mean over 300mm - what often defines the grade.
e - max deviation from mean over entire screw - basically the worst part of the screw + and worst part - off the mean. this spec is less relevant unless you need crazy precision.
E - acumulated deviation from target pitch over entire screw - only seems to be labeled on ground screws.

[millhead]

Here are the pictures from my X2 mill with Chinese ball screw conversion.

The Y axis (short one) is very easy as the nut fits nicely in place of the original acme nut. The X axis was a bit harder... Had to grind out half of the ball nut flange and gring a 2mm deep recess at the Y carriage. The cast irom from the X2 frame cuts as butter so that is not a big deal, but the ball nut flange ate an entire grinder stone!

Hope it helps.

They also sell a smaller 12mm Ballscrew (1204).
Will this be a better fit for the X2 X axis? Would a 12mm Ballscrew be rigid enough for the X axis?

I was on the verge of ordering a 1204 for the X axis, and 1605 for the Y, but thought I should get some feedback first.

Thanks.

Daya.

[Flenser]

I have a 1204 on my G0602's x-axis. It has worked well for almost a year, with no measurable backlash. I don't know why it wouldn't work for the X2. It's stiff enough. I guess the smaller balls might wear out a little faster than on the 1605.

[Davo J]

I bought my ballscrews over 12 months ago, but looking at his auctions tonight I notice his prices have gone up.
Reading this maybe the quality needs to go up not the price? That seems to be a lot of variation betweeen 2 screws.

Dave

Hi Viteq.
Of course I contact yesterday. Every body recomend him but about the costmer suport hi is bad. I don't think hi will replace anythig. I ask him one question but hi reply another. Just take and look on the email.
Dear anyshka_23,

Dear Alex,
Our ballscrew is C7 class. And this is Rolled one.
We don't have Ground ballscrew with C3 class or better. As you know know the Ground ballscrew is much much higher in price.
Thank you in advance for your understanding.
Chai


- linearmotionbearings2008 Click "respond" to reply through Messages, or go to your email to reply






--------------------------------------------------------------------------------
From: anyshka_23
To: linearmotionbearings2008
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
Sent Date: 2010-07-16 03??24?37?





Dear linearmotionbearings2008,



Yes I belive this need to be. And maybe is but I told you my problem They are not 1605 this means one of my ballscrew have pich 4.985 and another have pich 4.995.
If you want replace me just one dosn't meater wich, but to be with the same pich.
I going to use on the same axis on cnc and I need to be identical pich.
If you going to help me to fix this problem please do. If you didn't want pleace tell me from start. I buyed from you because everyboby on cnczone and another forums recomend you, but from wath I see right now this is one of the big fals.
Thank you for understanding.
Alex

--- On Thu, 7/15/10, eBay ??: linearmotionbearings2008 <[email protected]> wrote:


From: eBay ??: linearmotionbearings2008 <[email protected]>
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
To: [email protected]
Date: Thursday, July 15, 2010, 9:58 PM




Dear anyshka_23,

Hello,
The ballscrew assembly (Ballnut and Spindle assembled) Precision rolled, class 7 accuracy; JIS (0.050/300mm) (0.002"/12")
Ballnut: Single ballnut with zero backlash (<0.015mm) (0.0006")
Thanks!
Chai


- linearmotionbearings2008




--------------------------------------------------------------------------------
From: anyshka_23
To: linearmotionbearings2008
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
Sent Date: 2010-07-16 01??15?10?





Dear linearmotionbearings2008,



Thanks for reply chai.
I belive they can reach C5 but my not get C7.
The problem is onother. They are not the same and I can't get the result that I want. If you going to pay shiping back I can send to you back. If is not resonable to you send me just the screw and video how to replase the nut. I don't know?
I tried to ajust from software but I can not. I wiil post the reply from software company.

Hi Alex,

I am afraid that you are not going to like my answer - you cannot have a slave axis with a different ratio than the master, they both need the same steps per... =/

Thanks,

scott
--
Scott Nichols
License Manager
www.machsupport.com

----- Original Message -----
From: alex djamalutdinov
To: [email protected]
Sent: Thursday, July 15, 2010 9:30 AM
Subject: Please help.


Hello.
This is Alex
I have licence "XXX"
I need some help because i did;n find on the forum and Yahoo.
My problem is next.
On the X axis I have slave the A axis. I discovery last nigth my bollsrew are not the same.
One have pich 4.995 mm and other have 4.985 mm. I tryed to change the the unit per mm but they allweys read the master axis.
Is some way to solve this problem.
Thank you.
Alexandru.
Georgia Atlanta
404-447-4241

How we can fix this problem?
O do not have another way. They are need to be replace.
Thank you again for understanding.
Alex
--- On Thu, 7/15/10, eBay ??: linearmotionbearings2008 <[email protected]> wrote:


From: eBay ??: linearmotionbearings2008 <[email protected]>
Subject: Re: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
To: [email protected]
Date: Thursday, July 15, 2010, 7:12 PM




Dear anyshka_23,

Dear Alex,
Our screws are from Taiwan, world famous TBI brand. The website:
www.ballscrew.com.tw
I said it C7 class. In fact, that can reach C5 class.
Thanks!
Chai


- linearmotionbearings2008




--------------------------------------------------------------------------------
From: anyshka_23
To: linearmotionbearings2008
Subject: anyshka_23 has sent a question about item #250665434970, ending on Aug-11-10 11:12:58 PDT - 3 anti backlash ballscrew RM1605-200/650/1000mm-C7 cnc
Sent Date: 2010-07-15 22??16?40?


Dear linearmotionbearings2008,

Hello Chai.
This is Alex.
I bouth for yor you 3 ballscrew and one spindle this year. The ballscrew was 1605 and have aprox 1 - 1820mm and 2 - 1860mm . I ansambled my cnc last week and I discovery one ballscrew have pich 5 mm, another have 4.995mm and another hava 4.985 mm. This means when I turn 200 rotation the gantry is move:
1 ballscrew 997mm
2 ballcrew 999mm
3 ballcrew 1000mm
All 3 ballscrew are for X and for Y axis.
The biguest problem is the first and second ballcrew are slaved(they need to turm in the same time), and I can get acuratci result. If they was both the same 4.995 or 4.985 was no problem, but in this case I can not ajust from the software.
I think this result is not C7. Anyway haw we can fix this problem? I need 2 identical ballscrew.
I leave in USA, GA, Norcross, 30092
Thank you for understanding.
Alex.


- anyshka_23

[ihavenofish]

I bought my ballscrews over 12 months ago, but looking at his auctions tonight I notice his prices have gone up.
Reading this maybe the quality needs to go up not the price? That seems to be a lot of variation betweeen 2 screws.

Dave

there is variation between 2 screws, its the nature of the beast. order rolled screws from thk, or hiwin, or nsk and there will also be variation - although hopefully less as the price skyrockets. even ground screws have variation, but its specified in the tolerance. it still can be quite large though over a 1 metre screw.

fighting the screws wont help here. mach3 needs to allow independent screw compensation for machines with slaved axes.

[Flenser]

His prices haven't really gone up very much. The USD has gone down.

On his level of support, a couple of weeks ago my neighbor's kid removed one of the nuts from a 2005 screw laying on the bench and "lost" the balls that were in it. Chai sent me a new pack and refused to let me pay for anything.

[bogus105]

Hi guys,

so advice me what is better: to order ballscrew assmeblies from china (ebay seller linearmotion2008) or from rotton.com (they have cheap 5/8 dia screws for ca. $10/ft and square nut for it for ca. $23/pc) ???
which screws are better?
as for rotton i'm planning to order 2 nuts per screw: one fited and one adjustable for backlash elimination.

[bogus105]

Hi guys,

so advice me what is better: to order ballscrew assmeblies from china (ebay seller linearmotion2008) or from rotton.com (they have cheap 5/8 dia screws for ca. $10/ft and square nut for it for ca. $23/pc) ???
which screws are better?
as for rotton i'm planning to order 2 nuts per screw: one fited and one adjustable for backlash elimination.

[toneV8]

Does someone have picture of disassembled BK ball screw support ( fixed support side ) and BF ball screw support (floated side).

[LongRat]

Free end:



Drive end:



These are all from Linearmotionbearings2008.