I recently bought an MT3 parallel setup bar from Chronos and used it to setup my Boxford AUD at the weekend. I'd just levelled it and was chuffed to find there seems to be essentially no out-of-parallel error in the lathe slides.
If I traverse the saddle with a um reading dti on the side of the bar there is only about .003mm ( a tenth of a thou) total runout in the whole 125mm length of the bar. Turning the mandrel by hand with the dti at the far end gave similar readings.
With the dti set on top of the bar I got a much worse reading of around .04mm (1.5 thou) with the lathe mandrel pointing upwards towards the tailstock. I did some elementary trig and it seems that should have essentially no effect on accuracy (except perhaps on tiny turned diameters) and I wondered what the opinion of the group is on this misalignment ?
Is there a way of adjusting this out on a Boxford, or should I just forget about it ? Or are all lathes set up with the headstock pointing upwards for some obscure reason akin to the one relating to facing always being a smidgen concave ?