FILENAMES:

Spider.gif

DESCRIPTION:

This is a drawing of a "spider" device to aid in boring lathe
jaws. Thanks to AL <alicecurtis@worldnet.att.net>. AL provided
the following description:

>A spider is a tool used to hold tension on the jaws
>of a three jaw chuck when boreing soft jaws.
>It is made from a ring which has three drilled and
>tapped holes about the periphery.(see spider.gif)
>Three bolts are threaded into the holes until they
>are at such a diameter that the jaws close tightly
>at a slightly smaller diameter than the part that is to be
>held.
>A boreing bar is then used to bore the jaws until  the
>part will just barely slip into the pocket.
>the jaws are released and the part is clamped in the
>jaws, this is good for finishing the back side of a
>workpiece or when a workpiece is too fragile to be
>held in hardjaws.
>I have also seen jaws milled to hold square or other
>odd shapes.