In a previous article I described fitting an HTD belt drive to the head of the X3 mill. The reason for doing this was to reduce the amount of vibration of the tool and to consequently improve the surface finish of the clock parts profile with CNC. The HTD belt did improve the finish I obtained, never the less I decided to see if I could improve the finish even more by replacing the head and the spline drive spindle. (Mills with a quill feed have a sliding spline arrangement, which in order to slide freely, must have slight backlash, which in turn can cause vibration.) I decided to make a head with a plain ball race spindle driven with an HTD belt by a variable speed DC motor. For ease of construction the spindle would be bolted on to the front of the head. To ensure the spindle was set precisely vertical the front and back surfaces of the head were carefully machined parallel and the body of the spindle set between two clocked guide rails. Photo 1 shows the finished and fitted head and spindle.
展开▼
