Oil grooves and Deckels

A few days ago, I had to make a new bronze bushing for the piston axle of my vintage bar-cutter mower...

I was in a hurry because grass is growing incredibly quick now and I need that machine back together and running again asap, before I can't even open the door and get out anymore ! :D

Since the lubrication of the original bushing was only relying on three holes with inside chamfering, I decided to simply mill some kinds of oil pockets in the new bushing with the FP1.











Anyway, that lead me to think about how I'd do to cut "real" oil grooves in a bushing and thought I'd share my experiments. ;)
Here's the *very* quick and *very* dirty reality check I did Yesterday, to see if I could do it on the deckelS11 .

You need a combination of a circular and a linear motions, but unlike what's going on when you thread on a lathe or grind an helix on a tool grinder grinder, the linear movement must change its direction every half-revolution of the spindle...
So the idea is to replace the spiralgrinding attachment with a simple cam, and a fixed stop. The cam is circular, but features a slot allowing to de-center it.
It is mounted on the gear that drives the workhead spindle when spiral grinding and rests on a fixed stop attached to the sine bar of the spiral grinding attachment.
Of course, since the S11 is a tooland cutter grinder, its table is free to move axially.
Therefore when spinning the workhead spindle while applying the cam on the stop, each revolution of the spindle generates a linear motion equal to the cam offset.

The pictures are from the quick test I did with a sharpie, to see the groove path the circular cam would generate.












Some tweaking left, but already quite good !