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

On 2013-05-06, 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




Kurt sells power drawbars.

i

Looking at the drawings of NMTB 30, CAT 30, BT30, looks like they would all
work in an NMTB spindle with the appropriate drawbar. I've mostly looked at
the internal taper dimensions, not sure about the drive keys fitting all.

I was thinking about getting a pull stud style CAT or BT 30 toolholder and
seeing if I can make a spring loaded pull stud drawbar for it. If not, I
would at least like to be able to use it with a threaded drawbar.

RogerN

"RogerN" fired this volley in
m:

I've mostly looked at
the internal taper dimensions, not sure about the drive keys fitting
all.


The only thing I'm sure of without looking at prints is that most NMTB-30
toolholders will fit a QC-30 spindle. (we've got a good mix of brands,
mostly European, including ONE Chinese holder... guess which one doesn't
fit G). When they don't, it has always been (for us) because the
toolholder's flange is too thin (by about 0.050) to be gripped by the
locking collar.

LLoyd

On 06/05/13 07:04, 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



Not an Erickson spindle but here is a power drawbar drawing for a
Denford Triac CNC mill www.denfordata.com/bb/download/file.php?id=897 .
Actually the tool holder is held in by the disc spring stack and either
hydraulic or air used to push the pull stud holder out. IIRC the tool
holder used is BT30.

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.

"Pete C." wrote in message
...

- 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.


Not in my experience, although a quill-type spindle cartridge does need to
have a means of positively locking it in the full up position.


- 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.


Hammering on the top of a conventional drawbar is the usual method, which
doesn't seem to damage spindle bearings so far as I've been able to
ascertain.

PrecisionmachinisT wrote:

"Pete C." wrote in message
...

- 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.


Not in my experience, although a quill-type spindle cartridge does need to
have a means of positively locking it in the full up position.

The machines I used to work on were this way, perhaps designs changed in
recent years. The force was always applied between the spindle and the
drawbar such that no force was applied to the spindle bearings.



- 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.


Hammering on the top of a conventional drawbar is the usual method, which
doesn't seem to damage spindle bearings so far as I've been able to
ascertain.

A rap with a hammer vs. pressing hundreds of pounds with a hydraulic
actuator. Perhaps they've beefed up spindle bearings in recent years as
spindle speeds have increased so they can more readily handle the
toolchange load. Or perhaps you haven't looked at the actuator closely
enough since without looking at the prints it's not immediately obvious
that the force is not applied to the bearings.

"Pete C." wrote in message ...

PrecisionmachinisT wrote:

"Pete C." wrote in message
...

- 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.


Not in my experience, although a quill-type spindle cartridge does need to
have a means of positively locking it in the full up position.

The machines I used to work on were this way, perhaps designs changed in
recent years. The force was always applied between the spindle and the
drawbar such that no force was applied to the spindle bearings.



- 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.


Hammering on the top of a conventional drawbar is the usual method, which
doesn't seem to damage spindle bearings so far as I've been able to
ascertain.

A rap with a hammer vs. pressing hundreds of pounds with a hydraulic
actuator. Perhaps they've beefed up spindle bearings in recent years as

The actuator bottoms out internally after the tool releases, thus the max pressure that is placed onto the bearing is the same in either case.

spindle speeds have increased so they can more readily handle the
toolchange load. Or perhaps you haven't looked at the actuator closely
enough since without looking at the prints it's not immediately obvious
that the force is not applied to the bearings.

No, it's immediately obvious from my having actually worked on them for going on 35 years now.

PrecisionmachinisT wrote:

"Pete C." wrote in message ...

PrecisionmachinisT wrote:

"Pete C." wrote in message
...

- 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.


Not in my experience, although a quill-type spindle cartridge does need to
have a means of positively locking it in the full up position.

The machines I used to work on were this way, perhaps designs changed in
recent years. The force was always applied between the spindle and the
drawbar such that no force was applied to the spindle bearings.



- 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.


Hammering on the top of a conventional drawbar is the usual method, which
doesn't seem to damage spindle bearings so far as I've been able to
ascertain.

A rap with a hammer vs. pressing hundreds of pounds with a hydraulic
actuator. Perhaps they've beefed up spindle bearings in recent years as

The actuator bottoms out internally after the tool releases, thus the max pressure that is placed onto the bearing is the same in either case.

The max compression of the belville spring washer stack is constant,
yes. The pressure will vary if a washer or two has failed, and again on
no machine I have worked on was any of this force applied to the $800
spindle bearings. The actuators all floated and pushed down on the
drawbar while effectively pulling against the flange on the spindle as
opposed to being rigid mounted to the head casting and pushing down
against the drawbar. This was dozens of different brands and models of
machine.


spindle speeds have increased so they can more readily handle the
toolchange load. Or perhaps you haven't looked at the actuator closely
enough since without looking at the prints it's not immediately obvious
that the force is not applied to the bearings.

No, it's immediately obvious from my having actually worked on them for going on 35 years now.

Well, I worked on them as in serviced them for about 6 years, including
changing out belville washers on the drawbars and replacing a few sets
of spindle bearings, so there is no question that the machines I worked
on then ('90-'96 or so) did not apply toolchange forces to the spindle
bearings. Take a close look at the prints for one of your machines to
see where the force is really being applied.