Setting up work on the rotary table

[irving2008]

....., a dial indicator (DTI) needs to be mounted on a suitable holding device clamped to the spindle. Articulate holding device (indicator clamp) to indicate four sides (square part) or two opposite sides (rectangular part) and two 90 degree sides (again rectangular part) to indicate zero from x minus, x plus, y minus, y plus (hand rotating spindle then twiddle spindle to indicate zero). ...

Thanks for that. No, not too complex, and thats pretty much where I'd got to myself.. I was hoping someone had a clever solution that wasnt the obvious one, but why do i need to put DTI in spindle for rectangular part? Why not on bed, indcate side 1 then rotate table 180 and indicate side 2, then tap into place, repeat for sides 3 & 4?

[irving2008]

Exactly so... so once I got the rotary table centred under the spindle i'd lock the gibs on the main table. Then I clamp the workpiece to the rotary table roughly centred, turn the table so that the dti was set up against one edge of the workpiece, then rotate table 180 and indicate offset on opposite side, then tap workpiece with mallet to correct. Repeat til centred... the repeat for other 2 sides....

wheres the catch...there has to be one!

[Peter Griffin]

Instead of using the rotary table why not just pitch the holes using good old fashioned Trigonometry

[irving2008]

of course I could Peter, and indeed on the first one I did... but now I've got the rotary table I can bore the central hole and the surrounding holes completely concentric and I only need to move the table once - to offset the spindle, after boring the central hole, by 1/2 the PCD of the surrounding holes. Thats got to be more accurate.