I just finished a neat part that would have been very difficult to machine without a rotary table. I thought the following accelerated fabrication video might be of interest (there are comments in the lower right corner). I sure wish I could fabricate parts that fast!
The part is a spacer that sits between the custom front accessory mounting plate and the automatic tensioner. It accomplishes the following:
Aligns the tensioner/pulley with the accessory serpentine belt.
Provides a boss that indexes the inside of the tensioner’s mounting hole to ensure no lateral movement.
Prevents the tensioner from rotating by capturing its anti-rotation post.
Enables the tensioner to be clocked.
Since the entire serpentine system is custom, I wasn’t sure of the belt length so it was important that I could easily clock the orientation of the tensioner. After some thinking I came up with the following solution which enables it to be clocked 360 degrees in five-degree increments:
The mounting plate has six sets of mounting holes located 30 degrees apart
The spacer has three sets of tapped mounting holes located 20 degrees apart
The spacer has two anti-rotation holes located five degrees apart when the spacer is rotated 180 degrees.
When I need to measure something accurately, I often 3D print mini tests to validate dimensions. As can be seen below, it usually takes multiple attempts to get it near perfect. In this case I was dialing in the ID of the mounting hole, the OD of the anti-rotation post, the center-to-center distance of the anti-rotation post and the mounting hole, the angle of the anti-rotation post and the arc of the tensioner.