Near the end of my spoil board hole boring, I noticed that several holes did not bore more than 0.25" from the top.
During the CNC operation, I touch the Z belt, LEFT side and noticed that it was really loose as compared to the RIGHT side. As the Z axis move further down it’s travel that’s when the left side of the belt was loose. As the Z axis move upward, the left side of the belt got taut.
Prior to all this I removed the Z belt to inspect it for a bad tooth or loose screws, etc. My reason for this inspection was I could “SOMETIMES” hear a clicking sound and the bottom of the Z axis travel. My inspection did not reveal anything out of the ordinary so I reinstalled and pressed on.
Today, I checked the Z belt tension and it was taut. Even at the bottom of the Z axis travel, both the left and right were taut.
I am confused … could it be that after performing more than 100 holes, the Z belt stretched from operation heat?
Most likely the problem is that the bolt vibrated loose — some folks have added a jam nut (or pair of them) to it, others have used a bit of threadlock — the belts have a very wide operating temperature range.
Not sure I understand … This was assembled at the factory.
All I did based on the above pic was put one side of the belt on the motor pulley and the other side of the belt on the dual sandwich bearings.
I then lightly fastened the dual bearings to the plate and with the Z axis at its max downward travel, I tighten up the hex screw tensioner till the belt is taut. Followed by fully tightening the dual bearing nut and bolt.
We may have made a mistake at the factory (we’re human, not perfect). Please take a photo which shows how the pulleys on the X-axis and Z-axis motors are arranged, or check them against the photos in the assembly instructions.
