Seig Sx2.7 Milling Machine

[Niros]

Have you adjusted the gibs?

Tom

I didn't, it has a one screw mechanism, so it will only tighten or loosen the axis movement, I don't see any rotational play. In any case I locked the axis and the locking mechanism just pushes on the gib. (All the measurement I took are height measurement)
In any case, does a ~0.05 mm flatness along the y axis over 160 mm is considered bad? (In my opinion it is terrible)
My main question is, based on your experience which I lack, replacing the mill is a smart move? should I anticipate improvement or the same story? I don't have the time to take it all apart and reassemble it from bottom up. Maybe in the future, but not just yet... Do you think the picture I described worth the replacement? or it could get even worse than that? I mean 0.04 mm on all parameters is something I can live with for the moment.... But 0.4 mm is just ridiculous... (My press drill does better than that with my (cheap) USA x-y table...)

 

[higgite]

I didn't, it has a one screw mechanism, so it will only tighten or loosen the axis movement....

The gib for each axis has two screws, one at each end of the gib, for adjustment.

In any case, does a ~0.05 mm flatness along the y axis over 160 mm is considered bad? (In my opinion it is terrible)

I haven’t measured the flatness of my table, so can’t offer anything there. I can tell you that my table is out of tram with the spindle by .00025” over 5” (0.00005”/inch) on the Y-axis and .0019” over 16” (0.00012”/inch) on the X-axis. I have never adjusted it.

My main question is, based on your experience which I lack, replacing the mill is a smart move? should I anticipate improvement or the same story? .... Do you think the picture I described worth the replacement? or it could get even worse than that?....

That’s difficult to say without actually witnessing how well your gibs are adjusted, how you took your measurements, etc., etc. And I’m a little confused if you’re talking about table surface flatness or table tilt relative to a level surface or to the spindle or what. If you are convinced that your gibs are properly adjusted and the mill is still out of spec, then what do you have to lose by requesting a replacement? I hope you get it worked out to your satisfaction.

Tom

 

[Niros]

Tom, thank for your reply, first I want to say that you where absolutely right! you are the first person to point out to me that I should play with the gibs ant it has a huge effect on accuracy! I took the offer for replacement, before I took your advice into consideration (The mill was in the box already) and the first thing I did on the second mill was to check for the gibs. I reassembled them after cleaning them along with the machine and applying thin coat of engine oil 10w40. The height measurement along the x axis relative to the spindle gave 0.03mm and on the y axis it was about ~0.1 on both sides - nothing that can't be fixed with a shim. However I did got a very inaccurate z column it has the shape of a trapeze… The top is much wider then the bottom. If I close the gib when the head is at the bottom all the way in - when I lock the head it still moves to the left by 0.27mm! and I cannot move the head all the way up! I shared all the details in https://www.model-engineer.co.uk/forums/postings.asp?th=168066&p=1 and I really am disappointed from this mill. Now I need to ask the seller for a third replacement - If he accept it - I'll have to pay him extra, and then I will need to pray this time I will got better luck... I cannot upgrade to Sieg SX3 since it is too heavy and I live in an apartment where the maximum allowed weight per meter is only 150 kg and there is no reason to think that the Sieg SX3 will be more accurate.

 

[CraigH]

I declined to tram my SIEG 2.7 (in LMS 5500 form) because of concerns stated above.

In fact it is not too bad. Given lack of rigidity, loosen bolts, and on the side to have shims inserted, push on the column and insert the shims - retighten bolts. Repeat a dozen or more times. I did this is rather close quarters. And I am not particularly strong these days.