RogerN wrote:

My home shop CNC mill is a Bridgeport with an Anilam Crusader II controller.
Last time I switched it on, the controller didn't power up. I've been
wanting to do the LinuxCNC upgrade on it anyway and this looks like a good
time to do it. LinuxCNC will give me greater capabilities with the machine
than the original control was capable of.

... So I'm considering automatic tool changing but I would need to convert
my Erickson QC30 spindle to a pull-stud drawbar. Looking at the tapers, the
CAT 30 or BT 30 should fit but be shorter than the QC 30, leaving me room to
make a pull stud drawbar. Something like:
http://www.practicalmachinist.com/vb...ible-mac_p.jpg

At first I plan to just set the tooling up on the table, something like
this:
http://www.youtube.com/watch?v=BYj_HVDn08Y

Anyone here know of anything like an Erickson QC 30 to pull stud drawbar
conversion? Or a drawing of the inside of the Erickson spindle?

RogerN

A few key things to keep in mind for such a conversion:

- Toolholder retention is via a stack of belville washers that exerts a
*lot* of force to pull the toolholder into the taper. This is why the
actuator is usually hydraulic as it would take a very large dia
pneumatic cylinder to get the required force to release.

- The actuator mechanism is "floating" and thus has no contact with the
spindle when a toolchange is not taking place.

- The actuator mounting will lift from it's non-contact idle position
when actuated so it is in contact with a flange at the top of the
spindle while pushing down on the drawbar. This is so no toolchange
force is applied to the spindle bearings which could damage them.

- The actuator travel is such that the drawbar will apply a push to the
toolholder at the end of the stroke to pop free a sticking toolholder.

- Air is usually piped into the spindle and switched on during the tool
loading to blow out any chips that may be on the toolholder taper.