[SwampDonkey]

Hi fellow Tormachers!

Well, my machine is almost 10 years old. Its an early series 1 thats been upgraded to series 3 electronics. Im happy to say that mechanically its still solid as a rock. No detectable wear on the ways, table is still in good shape. But the Y axis ballscrew may have an issue that warrants either adjustment or replacement. Since I could find no literature online about replacing the ballscrew, I thought I'd ask you guys for advice before I turn a bolt.

Have any of you done this before? Anything to keep in mind?
Should I buy a direct replacement or go for a more accurate screw via Ebay if one comes up?


And the bonus:
I have a touch probe very to the Tormach version except it has a 3.5mm "audio" jack instead of a 5 pin DIN plug compatable with the tormach aux recepticle. Is there a pinout of the Tormach female DIN aux floating around, or have any of you wired up something similar? Im sure I could locate the gnd and 5V pins but know the aux has provisions for other accessories and there may be more than one 5V on there. So which would be correct for the probe?


And as always, thanks in advance.
Cheers,
SD

[keen]

Hi fellow Tormachers!

Well, my machine is almost 10 years old. Its an early series 1 thats been upgraded to series 3 electronics. Im happy to say that mechanically its still solid as a rock. No detectable wear on the ways, table is still in good shape. But the Y axis ballscrew may have an issue that warrants either adjustment or replacement. Since I could find no literature online about replacing the ballscrew, I thought I'd ask you guys for advice before I turn a bolt.

Have any of you done this before? Anything to keep in mind?
Should I buy a direct replacement or go for a more accurate screw via Ebay if one comes up?


And the bonus:
I have a touch probe very to the Tormach version except it has a 3.5mm "audio" jack instead of a 5 pin DIN plug compatable with the tormach aux recepticle. Is there a pinout of the Tormach female DIN aux floating around, or have any of you wired up something similar? Im sure I could locate the gnd and 5V pins but know the aux has provisions for other accessories and there may be more than one 5V on there. So which would be correct for the probe?


And as always, thanks in advance.
Cheers,
SD

Hi SD

So you have excessive Y axis backlash? Please give us the details..... results of your Y axis tests.

In the mean time here is a little background video on dismantling and ballscrews.

Keen

https://www.youtube.com/watch?v=EchELgqGz-c

[Concepts_Design]

this pdf for the tormach passive probe shows the pins

[R.DesJardin]

I did mine from underneath. I had a metal table that's open on top so I could reach through.
I thought the Operators Manual glad a pin out for the plug.

[SwampDonkey]

Good morning Keen!

Yes, it has gone from .002 when I got it 4 years ago, and now its up to .006 or so. I have a DRO so its easy for me to compare the readout with the interpolated DRO on PP. First thing im going to do is replace the bearings since I know they dont last forever and can cause these issues.

[keen]

Hi SD - yes breakfast posting.

You might be able to do a test to see if the backlash is in the thrust bearings or the ballnut/screw.

On Y axis direction reversal, If the ballscrew has lengthwise movement of most of your 0.006 then the slop issue should be the thrust bearings, if it does not move lengthwise the slop issue should be the ballnut/screw.

Cal you get a plunger indicator to the ball screw end?

keen

[MichaelHenry]

Yes, it has gone from .002 when I got it 4 years ago, and now its up to .006 or so. I have a DRO so its easy for me to compare the readout with the interpolated DRO on PP. First thing im going to do is replace the bearings since I know they dont last forever and can cause these issues.

It's also possible that the Y-axis ball nut mounting SHCS are loose, especially on a machine that has seen a lot of use, like yours probably has.

[GLCarlson]

Check page 8-12 of the Series II manual, rev A2. That shows the interface (for a Series II, maybe for a I and maybe for all machines) to be 5vDC on pin 1, 12vdc on pin 3, INPUT to pin 5, and pin 4 as DC common. This isn't inconsistent with the info posted earlier on the probe, by the way; pins 4 & 5 are indeed the input- it's just that there is power on some other lines. Pins 1 and 3 are specifically called out as being available for powering external circuits (no current given), and pin 4 is LOGIC GROUND, NOT machine ground- specifically, do not attach pin 4 to machine ground. Pin 5 is pulled up to 5v via an LED and 470 ohm resistor, and is the input to a 4N35 optoisolator.

I'd specifically check for 12v on pin 3 and 5 v on pin 1, both referenced to pin 4.

[keen]

It's also possible that the Y-axis ball nut mounting SHCS are loose, especially on a machine that has seen a lot of use, like yours probably has.

Hi Michael. I agree it could be loose - but if it is I believe it would be due to an assembly fault eg burrs or chips or paint etc under the assembly or a not flat mating surface, all quite possible - allowing it to rock loose over time.

If correctly assembled I doubt it would never come loose.

Keen

[MichaelHenry]

Keen, you might well be right. All of the screws on my X-axis ball nut mount were loose, but I'd disassembled it a few years before the problem occurred and may not have properly tightened them up. If it happens again would you recommend a medium duty thread locker?

[keen]

Keen, you might well be right. All of the screws on my X-axis ball nut mount were loose, but I'd disassembled it a few years before the problem occurred and may not have properly tightened them up. If it happens again would you recommend a medium duty thread locker?

Probably a good tighten is all that is needed, but if you don't fully dismantle and manage to clean up the mating surfaces, then the issue could remain that started the movement... so a thread clean and mild thread lock may help. I wouldn't use anything too serious as you may have trouble loosening in the future.

Keen

[Paul-JB]

Not sure if it matters but If I recall, there are taper pins in the nut housing in addition to the shcs's. They should be keeping the block from shifting. Of course if the shcs were loose from the beginning then I could see it working loose. I agree with simply tighten the screws good and make sure the pins are tapped in.

[MichaelHenry]

Hi Paul,

You're right, there are taper pins that align the nut housings. In my case, I think they might have loosened somehow but I can't swear to it. I do know that tightening the SHCS significantly reduced lost motion on my mill.

[lixingwen1987]

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