Re: [CAD_CAM_EDM_DRO] Re: Locating already drilled holes

Anne Ogborn wrote:

> Uh, I've used the method of putting a piece of drill rod of
> appropriate size in the spindle, laying the part loose on the bed,
> bringing the spindle down into the hole, then clamping the part
> to the bed. Is this OK practice? (Annie's no machinist).

It works, but if you put the drill rod in a Jacob's chuck, it will
likely
be a little off center, therefore the hole will also not be exactly
under
the center of rotation of the spindle.

A dial test indicator held in a mechanism that clamps around the spindle

can read off the inside of the hole. As you rotate the spindle by hand,

you can see the change in indicator reading, and adjust the table until
the hole is exactly under the spindle's center of rotation.

This, of course, only locates one point on the part, you still have to
worry
about whether the part is rotated to line up with the machine's axes.

Jon