[mrscheider]

Hi folks,
Tonight I went down to flip my stock after running a rough cut and then a finish cut. When I got to the machine I noticed the finish cut went bad. I just assumed a motor stalled. I jogged the axis' to see which stalled and found none of them did. Looking at the part, I noticed that the Y axis was off about an inch. I thought I must have zero'ed it wrong. Okay, I cut a new piece of stock, viced it up and started to jog the tables to begin a new piece.
Thats when I noticed that the Y axis table stopped somewhere mid screw. Funny thing was the table wasn't moving but the screw was spinning!
I removed the Y motor and pulled out the table to check the brass splitnut.
It was intact but there was play in it so I tighted it down and reinstalled the table and motor. Works fine again but for the life of me I cant figure that one out. Anyone else seen this before?
How could the lead screw turn inside the split nut WITHOUT moving the table?
It was running all day without issue till this occured.

Thanks,

Michael

[mrscheider]

bummer... the leadscrew is stripped in the center.
You cant tell but Im crying right now.
Anyone know the best place to get a new one and how big of a job is it to replace?
Still crying.
Thanks,

Mike

[TOC Admin]

Very simple fix.....Call taig, I just got a longer x Leadscrew from them

[jalessi]

http://www.taigtools.com/mmill.html

200-25 24.00 Y-Axis Leadscrew (LH)

[fretsman]

Hi Mike,

Forgive me as this is not to piss you off, but do you have any idea how it got stripped? In other words, shouldn't the nut have stripped before the screw itself? Anyone else run into this?

Reason why I'm asking is because "Mechanoman" (also a taig user) has run into a situation where he's found metal flakes in his way oil and he was concerned about it. I was under the impression that the nuts were sacrificial, not the screws........

I would have thought that one of the dealers with some knowledge would have popped in on that thread with some info, but none to be found. Maybe they'll see this one.

Thanks for your input and I'm sorry to hear about the downtime for you.

Dave

[mrscheider]

Hey Dave,
You know, it's a funny thing about that.. I really dont understand how this could have happened...
As I mentioned I was using the machine daily, the nut was never too tight, never run without lubrication.. It's very strange indeed that the screw stripped the way it did. I saw no evidence this was happening. The machine didnt lead up to this with a few inaccurate jobs or anything. Almost like it happened during the last job run. The screw was stripped down at about center of the length and only an inch and a half or so of the screw was stripped. I use two vices in an effort to prevent wearing one spot down but that really only benefits the X leadscrew since both vices center the work on the table. One thing for sure, the screw stripped right where it does the most work, it's just a little funny that it didnt show syptoms before failing. I mean, you should see this screw... the threads are ground down to the shaft!
I would think this kind of damage would have certainly been problematic for a week or so before stripping to the point that the screw turns but the table didnt move.
Know what Im saying?
Anyway, the nut seems to be in perfect condition. Yeah, go figure...
As I removed the leadscrew from it and got close to the end of the screw where the threads were pristine, the nut held snug with no play. A visual inspection also confirms the nut if in very good condition.
Dave, you bring up a very important point.
Why did the screw strip and the nut doesn't sustain any damage?
One last thing... I own the DSLS 3000 Taig. Are the leadscrews the same for all the Taig mill models?
Thanks everyone
Regards,

Mike

[cartertool]

I've never come across either problem (stripped leadscrew or metal flakes) so I can't hazard a guess, in both cases it would probably be wise to call or email Taig directly.
Also try the "contact us" email here:
http://www.taigmachines.com/Boss_s_Corner.php

I would have thought that one of the dealers with some knowledge would have popped in on that thread with some info, but none to be found. Maybe they'll see this one.

[jalessi]

Mike,

Are you sure nothing abrasive got into it?

Grinding or cut off wheel dust, iron filings, sandpaper particulates etc...

How old is your model 3000?

Taig is very good about replacing parts under warranty.

The part number I posted is correct for your mill, Taig will confirm it when you order.

Jeff...

[Jeff-Birt]

That is not something I have seen either. I would NOT reuse the old nut on the new screw. As others have suggest give Taig a call directly.

[jalessi]

That is not something I have seen either. I would NOT reuse the old nut on the new screw. As others have suggest give Taig a call directly.

Good call!

200-22A 18.75 Y-Axis CNC Leadscrew Nut (LH)

[mrscheider]

All,
I've taken a pic of the leadscrew..
I've done my best forensic work to try to figure out what could have done this without damaging the nut. I did find a few small chips of aluminum from stuff I've done in the past. I don't know if it played a part. I have to agree with Jeff, the nut will also be replaced even though, I have to stress that the nut shows no wear or damage. Zero. It threads onto the screw with ease and can be threaded snugly all the way up to the stripped section, at which point, the nut slides across and re-catches the threads on the other side. Very strange. I purchased the mill direct in January of 2008 and have probably put a good 1000 hours on it but all the other parts, ways, gibs, leadscrews, etc are still like new so something outside of normal use must have cause this.

[jalessi]

Please post some pictures.

[fretsman]

Hey Dave,
You know, it's a funny thing about that.. I really dont understand how this could have happened...
As I mentioned I was using the machine daily, the nut was never too tight, never run without lubrication.. It's very strange indeed that the screw stripped the way it did. I saw no evidence this was happening. The machine didnt lead up to this with a few inaccurate jobs or anything. Almost like it happened during the last job run. The screw was stripped down at about center of the length and only an inch and a half or so of the screw was stripped. I use two vices in an effort to prevent wearing one spot down but that really only benefits the X leadscrew since both vices center the work on the table. One thing for sure, the screw stripped right where it does the most work, it's just a little funny that it didnt show syptoms before failing. I mean, you should see this screw... the threads are ground down to the shaft!
I would think this kind of damage would have certainly been problematic for a week or so before stripping to the point that the screw turns but the table didnt move.
Know what Im saying?
Anyway, the nut seems to be in perfect condition. Yeah, go figure...
As I removed the leadscrew from it and got close to the end of the screw where the threads were pristine, the nut held snug with no play. A visual inspection also confirms the nut if in very good condition.
Dave, you bring up a very important point.
Why did the screw strip and the nut doesn't sustain any damage?
One last thing... I own the DSLS 3000 Taig. Are the leadscrews the same for all the Taig mill models?
Thanks everyone
Regards,

Mike

Hi Mike, just a really odd situation here, good luck and let us know how it goes with Taig

Dave

[mrscheider]

Hi guys,
I thought I did attach the picture.. Hmm... must not have .. I'll try again.

Mike

[DeusExMachina]

That is incredible, and disturbing. I don't understand how the brass nuts could ablate that much steel and not be damaged. It honestly looks like it was chucked up a lathe and something abrasive was run against that spot (which technically, stepper motor + nut [or 1k hours of hand cranking] would imitate pretty closely).

Oh, you should really dismantle the entire mill and thoroughly clean every moving surface, don't want any of the lead screw to get ground between the aluminum ways.

[jalessi]

What where you using to lubricate the lead screw and how often?

Are you using flood coolant?

What are you machining?

In the past some of our machines have worn like that, we try and move our fixtures or vises to extend the service life.

Repetitious wear patterns are tough to diagnose sometimes.

It could have been as simple as a improperly hardened screw.

I would thoroughly check, clean and lube your entire machine just to be safe.

Jeff...

[fretsman]

Wow, Mike, that's just amazing, I'm with DeusExMachina, and would completely rip the mill apart, inspect it, and make sure everything is clean.

Just incredible,
Dave

[mrscheider]

Isn't it the weirdest thing?
I use Castrol ATF and usually lubricate the system every three hours of run time. I'm very good about keeping to that time frame. Mostly because after three hours, if I dont relube, it sometimes will stall on an axis.
I don't use any coolant, I usually cut aluminum and brass but for the last month, Ive been milling wood.
The system IS basically pulled apart now... I did plan to clean it all really well before installing the new screw but I'm as stumped as you guys on how so much thread loss on the screw didn't damage that soft brass nut.
I'm paranoid on it happening again.. at least if I knew why it occured, I could avoid it.. but not knowing, geez... it could have been anything and I may just repeat it! lol

Regards,

Mike

[mrscheider]

Hi All,
I spoke to Cliff this morning at Taig. He's also clueless of what could have caused the problem but he is replacing the parts for me. Awesome guy!
Im sending him the damaged parts for closer inspection to see if he can determine a cause. Hopefully I will know soon.
Thanks all for your replies!
Kind regards,

Mike

[macdarren]

I wonder if the damage was not done by the split nut but rather maybe something got stuck between the frame and the lead screw. Acting like a lathe tool and messing up the screw as it turned against the contaminant until what ever it was worked its way out. I'll be curious to hear what Taig has to say.