Originally Posted by
handlewanker
Lapping??.......oh yes, I had to read post #17 again as I misread it as tapping......oops.
The problem still lies in the fit of the Y axis gib to both sides of the gap between the base casting dovetail and the saddle........this is a precise fit as the gib must touch both side faces EXACTLY.
As I said, this can only be done by careful observation of the blued areas and scraping.
At the same time you also FIRST need to determine whether or not the sides of the saddle dovetail and the base dovetail are true.
You need specifically shaped straight edges to determine that.........just bluing the gib and seeing bald spots only tells you one or more of 2 faces in the dovetail cavity and the 2 faces on the gib are not 100% flat.
What is the use of having a perfect gib if the dovetails are not also perfect.
YOU CANNOT FIT A TAPERED GIB TO A DOVETAIL UNLESS THE DOVETAILS ARE FIRST MADE TRUE.
The assumption here is that the dovetails themselves are perfect.......would you lay money on that?......and you also forget that there are other surfaces on the top and bottom of the slideways that must be perfectly fitted too.
So, now we have a more complicated scenario to pursue........otherwise you will end up with a machine that has dovetails that are all over the place.
My opinion is.....as this is a new machine that has been retrofitted, it would be fair to say that the quality of the machined surfaces are as good as it's going to get for the price paid...... so live with the "quality" you have purchased and go on to make chips.
Any subsequent messing with the slideways fit will not make things better........that is, unless the person doing the job is a machine tool fitter with the equipment and skill to work on cast iron slide ways dabbling with the machine will only make things worse......and there is no going back from that outcome.
Ian.