Fixing the spindle tram of EMCO FB2 milling machine

[compact8]

My FB2 has got a spindle tram error of 0.015 ~ 0.02 mm over a distance of 40 mm and I am thinking of doing something about it. The ideal solution of cause is to scrape the facing of the swivel joint of the head but I am wondering if it is possible to make a shim ( say, 3 mm thick ) and put it between the head and the vertical slide. The head is mounted to the vertical slide via only two bolts as shown in the picture. Will the shim affect the rigidity significantly ?

 

[frugalguido]

I question, are you talking about an error in the quill feed stroke or something else?

 

[markba633csi]

The real question is whether the main column is square with the table or is the error confined to the head only.
Which axis is showing the error? I think 0.015 mm is not bad- about 6 tenths (0.00059) inch
-M

 

[DAT510]

As Mark stated 0.015mm over 40mm out of tram is not bad.

Typically if adjusting Tram via shimming, one would shim the base of the column vs at the the head pivot. Unless you've determined the error is the two pivot mating surfaces not being parallel. Then I would think scraping would be the best solution. But Mr. Richard King can speak to that.

 

[compact8]

OK, I checked everythings again and found that the out-of-tram is not so much caused by the mating surfaces of the swivel joint being unparallel but the sloppiness of the squill ! I measured the spindle tram over a distance of 150 mm along the Y axis under different conditions and the results are as follows :

squill unlocked : front DOWN , only 0.02 mm
squill locked : front DOWN 0.06 mm
squill lowered by 5mm by operating the hand lever : front UP 0.06 mm
squill lowered by 40 mm ( travel limit ) by operating the hand lever : front UP 0.1 mm !

I think nothing can be done other than accepting that this is what to be expected for a hobby-grade machine ?