Ok, I've been playing with ,y Taig mini mill for a while now and I have some
idea of its limitations. I'm not quite ready to buy a lathe yet, but I'm
working on it. In the mean time I thought I might be able to make some
small parts if I could find a lathe style chuck to fit my mill.

It uses ER-16 collets so I was thinking, "just find a chuck with a 3/8
shaft, and use my 3/8 collet" There are a number of small inexpensive
chucks out there, but they all have a tapered shaft. At least all the ones
I can find.

For example
http://www.harborfreight.com/cpi/cta...temnumber=4486

If I had a lathe I could turn that shaft down to fit one of my collets, but
I'm not sure how to do that with my mill.

"Bob La Londe" wrote in message
...
Ok, I've been playing with ,y Taig mini mill for a while now and I have
some idea of its limitations. I'm not quite ready to buy a lathe yet, but
I'm working on it. In the mean time I thought I might be able to make
some small parts if I could find a lathe style chuck to fit my mill.

It uses ER-16 collets so I was thinking, "just find a chuck with a 3/8
shaft, and use my 3/8 collet" There are a number of small inexpensive
chucks out there, but they all have a tapered shaft. At least all the
ones I can find.

For example
http://www.harborfreight.com/cpi/cta...temnumber=4486

If I had a lathe I could turn that shaft down to fit one of my collets,
but I'm not sure how to do that with my mill.

I do have an idea though. Clamp the chuck on a piece of 3/8 rod stock. Put
the rod stock in the collet. Turn the whole think to get a nice straight
shaft on the chuck. Reverse the assembly and drop out the rod stock. I
would need to buy a piece of rod stock that was machined to pretty good
tolerance, and I would have to accept the imperfections of the jaws since I
would not be able to turn them to be perfect before clamping the rod in
them, but it should be ok for some crude parts.

My big concern is whether or not my Z-axis stepper motor would flake out
with the extra weight. I have to keep my Z-Axis lead screw well lubricated
now to prevent lift fails in some ranges.

There will be cumulative error from this method, but I should be able to
turn stuff within 5 thousands (plus the any slop in the mill head) if I
start with a purchased piece of precision rod stock. Of course this sets
off a-whole-nuther chain of ideas. LOL.

On Dec 20, 1:35*pm, "Bob La Londe" wrote:
...
...There are a number of small inexpensive
chucks out there, but they all have a tapered shaft....
For example
http://www.harborfreight.com/cpi/cta...temnumber=4486
...

The arbor screws into a 12mm x 1.0 tapped hole in the back of the
chuck.

jsw

On Dec 20, 4:45*pm, Jim Wilkins wrote:
On Dec 20, 1:35*pm, "Bob La Londe" wrote:

...
...There are a number of small inexpensive
chucks out there, but they all have a tapered shaft....
For example
http://www.harborfreight.com/cpi/cta...temnumber=4486
...

The arbor screws into a 12mm x 1.0 tapped hole in the back of the
chuck.

jsw

I wonder if you could bore out that hole and tap it to mm 22 x1.5.
Then you could use the chuck in place of the ER16 collet nut. Still
you might have problems turning the chuck. I'm not sure how robust
the Taig mill head is.

On Dec 20, 11:08*pm, "Denis G." wrote:
On Dec 20, 4:45*pm, Jim Wilkins wrote:

The arbor screws into a 12mm x 1.0 tapped hole in the back of the
chuck.
jsw

I wonder if you could bore out that hole and tap it to mm 22 x1.5.
Then you could use the chuck in place of the ER16 collet nut. *Still
you might have problems turning the chuck. *I'm not sure how robust
the Taig mill head is.

The boss on the back of the chuck is 23mm diameter with a groove for
the snap ring that retains the scroll, the black knurled ring. The
hole is 15.8mm deep to the back of the chuck jaws. The arbor extends
14mm into the chuck.

I'd look for a 12mm-1.0 tap with a shank that fits the ER collet and
use it as the arbor. I doubt you can find or make anything as straight
and concentric as a ground tap, especially without a lathe. Tap the
lock nut, then cut the tap off short to reduce overhang.

jsw

Bob,

I could make you an ER32 chuck to thread onto that... But the runout might
not be lathe quality... Maybe a few thousanths at worst. Probably not
terribly cheap either, but worth looking at if you are interested as it's a
no risk talk, eh?

Call and ask for Joe Jr. if interested.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill

V8013-R

"Jim Wilkins" wrote in message
...
On Dec 20, 11:08 pm, "Denis G." wrote:
On Dec 20, 4:45 pm, Jim Wilkins wrote:

The arbor screws into a 12mm x 1.0 tapped hole in the back of the
chuck.
jsw

I wonder if you could bore out that hole and tap it to mm 22 x1.5.
Then you could use the chuck in place of the ER16 collet nut. Still
you might have problems turning the chuck. I'm not sure how robust
the Taig mill head is.

I'm less concerned with the head being able to spin the chuck as I am my
stepper motor being able to consistently lift it with out skipping steps and
going out of calibration with my software.

The boss on the back of the chuck is 23mm diameter with a groove for
the snap ring that retains the scroll, the black knurled ring. The
hole is 15.8mm deep to the back of the chuck jaws. The arbor extends
14mm into the chuck.

I'd look for a 12mm-1.0 tap with a shank that fits the ER collet and
use it as the arbor. I doubt you can find or make anything as straight
and concentric as a ground tap, especially without a lathe. Tap the
lock nut, then cut the tap off short to reduce overhang.

The tap is not a bad idea if I could find one with a 3/8 shaft. Given its
nature I'ld probably want to lock it in place with green sleeve locker and
make it permanent. I suspect this is one of those things, I'm just not
going to be able to do to my satisfaction until I already have a lathe.
LOL.

"Joe AutoDrill" wrote in message
...
Bob,

I could make you an ER32 chuck to thread onto that... But the runout
might not be lathe quality... Maybe a few thousanths at worst. Probably
not terribly cheap either, but worth looking at if you are interested as
it's a no risk talk, eh?

Call and ask for Joe Jr. if interested.

I dunno. I think the taper inside the head meeting with the collet is how a
bit centers. The outside locknut and threads do not have to be as perfect.
May be compounded error there. Did I misunderstand how this stuff works?
Something screwed to the outside I think would not be as perfectly centered
as something clamped in the collet?

On Dec 21, 4:59*am, Jim Wilkins wrote:
On Dec 20, 11:08*pm, "Denis G." wrote:

On Dec 20, 4:45*pm, Jim Wilkins wrote:
The arbor screws into a 12mm x 1.0 tapped hole in the back of the
chuck.
jsw

I wonder if you could bore out that hole and tap it to mm 22 x1.5.
Then you could use the chuck in place of the ER16 collet nut. *Still
you might have problems turning the chuck. *I'm not sure how robust
the Taig mill head is.

The boss on the back of the chuck is 23mm diameter with a groove for
the snap ring that retains the scroll, the black knurled ring. The
hole is 15.8mm deep to the back of the chuck jaws. The arbor extends
14mm into the chuck.

I'd look for a 12mm-1.0 tap with a shank that fits the ER collet and
use it as the arbor. I doubt you can find or make anything as straight
and concentric as a ground tap, especially without a lathe. Tap the
lock nut, then cut the tap off short to reduce overhang.

jsw

Your solution is probably the best. I understand the difficulty of
getting the threads perfectly straight, but it's much more preferable
to have a thru hole in a lathe chuck and threading the chuck on the
spindle avoids the problems of having the chuck slip. Sherline chucks
have 3/4-16 threaded backs, which is close to the mm 22 x 1.5 size. I
found an odd fact in that both 3/4-16 and mm 22 x 1.5 are both
automotive oil filter threads. Maybe Bob could use oil filter parts
for a faceplate (although tolerences might again be an issue).

I could make you an ER32 chuck to thread onto that... But the runout
might not be lathe quality... Maybe a few thousanths at worst. Probably
not terribly cheap either, but worth looking at if you are interested as
it's a no risk talk, eh?

Call and ask for Joe Jr. if interested.

I dunno. I think the taper inside the head meeting with the collet is how
a bit centers. The outside locknut and threads do not have to be as
perfect. May be compounded error there. Did I misunderstand how this
stuff works? Something screwed to the outside I think would not be as
perfectly centered as something clamped in the collet?

Right now, how do your chucks mount?

I thought it was a 12mm X 1.5 male thread sticking out of your unit.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill

V8013-R

On Dec 21, 10:44*am, "Joe AutoDrill" wrote:
Bob,

I could make you an ER32 chuck to thread onto that... *But the runout might
not be lathe quality... *Maybe a few thousanths at worst. *Probably not
terribly cheap either, but worth looking at if you are interested as it's a
no risk talk, eh?

Call and ask for Joe Jr. if interested.

Regards,
Joe Agro, Jr.

In that case you could thread the outside of the chuck boss 22mm-1.5
and make a simple inside-threaded sleeve adapter. Then the bores of
the spindle and chuck would be open to accept long work pieces. The
Taig site says the ER-16 spindle has a 0.406 thru hole.

The boss extends 3.2mm beyond the snap ring. If you don't mind a
little adjustment when installing the chuck the sleeve could replace
the snap ring as the scroll plate retainer, this would allow longer
threads on the boss.

jsw

On Dec 20, 10:06*am, "Bob La Londe" wrote:

Ok, I've been playing with my Taig mini mill ...
It uses ER-16 collets so I was thinking, "just find a chuck with a 3/8
shaft, and use my 3/8 collet" *There are a number of small inexpensive
chucks out there, but they all have a tapered shaft. *

There's a reason for that; it self-centers when mounted.
Can you get a chuck with the same taper as your ER-16
collets' exterior? Use the collet-holding taper to center the
chuck, would be my preference. Chucks with R-8 taper,
for a Bridgeport mill, are a common item.