Accurate indexing on a rotary axis

dafunkdawg said:

I am not really sure how to ask this, but I will try. I have been trying to figure out a good method to be able to pull a part from the rotary axis them lock it back in place later accurately. I have been thinking about maybe some sort of jig with an index pin of some type and them figuring out a sort of home switch for the rotary. This is a cnc with a homemade rotary using a 3 jaw taig chuck with stepper on a piece of taig bed. Maybe I am overthinking it but would like to try a 6 or 8 point forearm and mage something in the butt sleeve that get cut and glued and them has something else cut back over it. Any ideas would be greatly appreciated

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you're searching for a Recut fixture.
got mine from John Rocker several years ago.
not sure who else is making them
maybe check with Chris Hightower

A lot depends on your rotary axis as to how the fixture is going to work. For best results,you need some way of making it repeatable to the axis orientation. Then it is just a matter of making something that stays with that particular part(shaft/handle/point material etc) until finished. A photo of 4th axis helps so much so others can see what you have and can then offer ideas etc. Repeatable setups is very common for industry and usually the simple solutions are best. If it is an electronic 4th axis, it a can often be easily referenced to any radial zero position. Manual diving heads are not usually easily referenced to zero, so often require the zero radial position to come from the fixture itself and to have some form of radial adjustment to achieve zero.
A simple taper on the end of a screw can often be all that is needed to make a part go back into the same place every time.
Neil

I use the Spur driver and cut a small slot in the end of the cue so the spur collar pin on the dead center can go back into the slot and line it back up again.

if your running steppers gear reduced to 6:1 or less then just do this:

turn off machine
turn on machine (stepper will energize and detent to nearest full step)
scribe a reference mark across 2 opposing faces
jog to this mark everytime

this only works with steppers....you might be able to get away with more than 6:1 but thats the point in my mind where it will likely get very close and difficult to differentiate the clock marks