[ahooper]

I have just purchased a Sieg SX2 and several accessories however when using the fine adjustment to drive down in to the work the head seems to get stuck then drop by a mm or so. I have set up a video of this however unfortunately the light coming form behind the machine was washing out the image. However you can see clearly the head dropping.

Sieg have responded saying that I am not using it correctly.

I have Lubed the slides, checked the adjustments and made sure there are not bits of swarf jammed in the guides.

[ame=http://www.youtube.com/watch?v=6Fmrn7sKduY&feature=feedfbc]P1020372-2.MOV - YouTube[/ame]

Any suggestions would be appreciated.

Regards
Andrew Hooper

[dfurlano]

My guess is the gibbs are too tight. Make the loose and try it again.

[ahooper]

Thanks, I Adjusted the Gibbs so that the head runs smoothly up and down on the course adjustment handle on the side. any loose and the weight of the head seems to overcome the balance spring and the head will slide down on its own freewheeling the course adjustment. not much change in the problem possibly a little worse.
Adjusted the Gibbs up an the problem seems a less but the fins adjustment becomes pretty hard to turn. however the problem is still there just not as bad.

[B-RAD]

Check through the first 3 pages in this sub-forum, you will find a few threads that says "LMS, 3900, Hi Torque" any threads with one of these words in the title will help you. I have one, and there are a couple others that are good too.

Here is one that will definately help you - SX2 Help

Simple answer is you will need to scrape (Google scraping, you can use a file...) and 600-1200 grit sand your ways and you will also need to sand your gibs flat... I used a piece of glass with some 230grit then 600grit wet sand paper to make them as flat as the glass... your arm will hurt they are so bad...

[ahooper]

Great, thanks for the pointer
Looks like a bit of work ahead of me and that pretty much describes the fault I have perfectly.

Cant wait to get it running correctly.

Andrew

[WaveDude]

any loose and the weight of the head seems to overcome the balance spring and the head will slide down on its own freewheeling the course adjustment.

Loose gibs should not have that affect on the spring-assist for the head. It sounds as if the spring isn't doing anything. I would investigate that closer.

[ahooper]

Thanks WaveDude, I will take a look and see what the tension on the spring is like. I pulled the head off and found that the gear on the main shaft that is connected to the handle had signs of wear on the teeth. considering this machine is less that 2 weeks old i'm pretty surprised. Yes it was lubed before use .

This could account for some of the play in the head adjustment.
Also the Gibb was quite rough, looked like it had been sanded with 60 grit. i'm not 100% but also looked like it had a slight curve in it.

I also noticed that when the gibb is adjusted toward the top so there is no play as you move the head down things get prety tight and there ends up being quite a bit of resistance on the head to the point of if you loosen the head at the top it will slide half way down then is overcome by the resistance no by the spring tension.

as for the spring tension, there was not much there when i pulled the head off. Certainly not what I would have expected then undone it rotates and sits upward just to the back of the machine still pointing upward.

[ahooper]

Wear on the Z Axis gear that drives the head up and down. This could be part of the problem however this machine was supposed to be brand new and was still in the box.

Before anyone asks Yes I lubed the gear's before I used it by putting grease on the other half and ruining the head up and down a few times. I had to wipe all the grease off the gear to take the photo.




Andrew

[ahooper]

well the gear is not the issue, I removed it for my CNC conversion and found that the same thing happened when running the head up and down. I end up with the head "Nodding" Gibb is now nice and smooth and I knocked off all the burs that may be causing an issue,
It all seems to slide pretty well just about half way the thing gives a few nods then seems to come right.
I have tried with and without the spring support and there is no change.

[B-RAD]

Did you run ur fingers along everything on the column and head? Somewhere I had waves I had to scrape.

[ahooper]

I will try that today, it seemed pretty flat to me and did not feel any waves or ripples. what i may do is set up a rail and use a dial gauge to see if its warped. also the supplier has another one they are going to clean down and test.

Still no response from Sieg on the problem. Also supplier is going to replace the gear. It looks like the gear has been subjected to quite a bit of stress that has caused the teeth to become offset.

Saying that however I have managed to set the CNC up and seem to be getting .05mm repeatable tolerance from the Z axis so far.

Regards
Andrew