Hi Guys,
After reading a recent post on here I think I may have a similar problem. It's a BMC 20 with ultimax 3, 1993 Y.O.M. I think. I've had my doubts as to the accuracy of this machine for a while but it's never been too much of a problem as the things I've made on it have never needed to be spot on. I had to clock a part in on a bore the other day and noticed something worrying.
When I tried to zero the clock in by moving the X axis there was an audible clunk when I moved the hand wheel form side to side. As I move the hand wheel back and forward the DTI needle jumps by 0.02mm but it jumps in the direction that I'm making the axis move. It does this in the Y axis as well. So I tried a test after reading the post about backlash.
I move the DTI needle up to a block on the bed and zero the clock, then move the axis in by 0.3mm on the clock dial then zero the axis part setup. Then I move the axis back out until the clock dial reads zero and check what the part setup reading is. I did this for both X and Y axis and the part setup reading was 0.272 for the X and 0.246 for the Y.
I could do a more accurate test with a DTI that was 0.001mm increments but would have to buy one. Thing is, am I looking at it in the right way. I'm planning a strip down of all the guarding and chip enclosure in the near future to fix all the leaks and cracked welds. If i can fix any other problems while I'm at it then all the better. So what do I need to do.
I don't know a lot about these machines and I learn as I go along so replies in laymans terms please, otherwise I'll get lost. It's the clunking that worries me, does something need to tightend up, or is it just worn parts. It has done 28,000 hours.
Any help.