like these fun machining jobs. This one is the idler pulley for the serpentine belt tensioner setup.
It starts out as a piece of 75mm diameter billet. Machine the outside down and face the end square. Then drill the center before switching to a boring bar. With the boring bar the center bore is enlarged and the various internal diameters turned. The center hole is machined to a close tolerance for the bearing to press fit into.
The edges are all chamfered before the pulley is cut away from the billet using a parting tool. The pulley is then flipped over and the back side machined.
With the lathe work done the pulley goes onto the milling machine. The part is mounted to the rotary table and that lets me accurately drill a ring of holes to reduce some weight. The edges of the holes are chamfered for a neat finish.
Here's the finished pulley with the bearing pressed in place. The part is as machined, it hasn't been polished.
A couple of relaxing hours in the shed not thinking about work, just concentrating on making something. Very Zen.
Cheers