"Bob La Londe" wrote in message ...

On 11/7/2019 4:24 PM, Carl wrote:
"Bob La Londe" wrote in message ...

On 11/7/2019 8:09 AM, Bob La Londe wrote:
How consistent is the ring on taper tooling?

I recently changed out the spindle on one of my small high speed
machines to an ISO20 quick change spindle. I'm trying to determine the
easiest way to measure tool length off the machine. As near as I can
tell the only purpose of the ring on ISO20 is to hang the tool holder
in a tool changer. To do that it really doesn't have to be all that
consistent.Well not as consistent as tool length measurement needs to
be. Do I have to use an actual tool zero, and machine or buy a taper
socket to set the tools in on the surface plate?

I'm not using a tool changer. Just doing quick changes and wanting to
use the tool table to reduce time doing touch offs. Just do it once at
the beginning of the job.

So far I really like the ISO20 spindle. Its already saving me a lot of
time over the ER spindle, and I have a second one ready to go in a
second machine when I have a spare afternoon to do it.


Lets try wording this a little differently:

One of my machines uses a tool holder with a flange that actually is
pulled up against the spindle face as it is locked in the spindle. This
makes it dead easy to measure tool lengths off the machine with a height
gage. I can measure on the machine with an electronic height setter or
measure on the surface plate with a height gage and as long as
everything is cool they measure within a couple tenths. Good enough for
the work I do, and far better than the machine itself is capable of.

On another machine I never set the tool lengths because they vary beyond
the Z travel, and its just faster and easier to crank the table down and
then crank it up until the tool zeros my 2" height setter. The machine
is always machine (home) set with Z-zero at +2" work offset. Atleast in
the G54 offset. I may use other values when using additional work
offsets. Its not as fast as a tool table with a bed mill, but its fast
enough.

My main work horses have 24K spindles with until recently ER spindle
noses. I had to use the height setter after every tool change. Sometimes
quite creatively. Recently I changed one out to an ISO20 spindle. Just
being able to push pull the 5 port air valve to swap tools saves me a
lot of time already, but I want to start setting up the tool table and
using M6 G43 to apply the tool height offset just like I do on the
machine in paragraph one.

However I have a problem. I am having a hard time wrapping my mind
around how to measure the tool length off the machine. I am wondering if
its even practical. An ISO 20 does have a flange, but as near as I can
tell its only purpose is to provide a way to hang the tool in a tool
changer. From what I understand the tool is only reference by how firmly
it is pulled into the spindle taper. To me that says I can only measure
the tool length offset on the machine its being used on. Am I missing
something? I guess I could have a physical tool zero instead of using
the spindle face, and have an iso 20 ground "socket" I placed on the
surface plate to put tools in to measure. Seems to me that would result
in different measurements of the same tool just depending on how firmly
I set the tool holder in the "fixture" setting on the surface plate.

This becomes more interesting because I have a second machine I plan to
upgrade to the ISO20 quick change spindle. Already have it on hand. Just
haven't had an afternoon to spare to make the change. If possible it
would be nice to use some of the same tools on both machines. If I could
get reliable relative tool lengths off (not in the spindle) of the
machines I could just measure once, and plug the value into both
machines saving me time.

I am a one man shop who started out as a hobbyist, and now pretty much
run continuously as my primary business. Taking time now to figure out
how to save time later is a cumulative gain. Five minutes setting tool
lengths might save more time over a year then shaving 20 minutes per
part off a 50 piece order.

I sincerely would like some help, guidance, or confirmation.

I have no experience with this but I wonder if you could put each
toolholder in your spindle and measure the distance between the ring and
some reference surface on the spindle? That would answer your first
question. Second, even if they are different, could you measure each
toolholder and engrave its offset on the ring? Then you just add that
offset to the tool length when you set up a new tool in that holder. Not
the "right" way others have posted where you have a socket on your
surface plate, but maybe it would be good enough?



I would not want to risk engraving as these are run at 24K RPM. It
probably would not fail catastrophically, but it might contribute to long
term bearing life. I have considered seeing if I could measure these
relative to the spindle, but I'm not sure how I would go about it. I don't
think a "stack of shims" would get me there.

The engraving was just for convenience at setup time so you didn't have to
track down the table of offsets for each holder. I was thinking of
something like a dial test indicator in a magnetic base attached to the
spindle head, so that the DTI arm rested on the top surface of the flange so
you could remove and insert holders in the spindle. Zero the DTI on the
first one, then the rest of the holders are relative to that one. Put a
tool in the first one and measure from tool point to the top of the flange,
and then use that plus the DTI reading for another holder to know what to
set the tool at in that holder. You will have to either make a fixture with
a hole that the taper drops through, with a flat surface so the cutting tool
is sticking straight up, and then set that fixture on your surface plate.
Or maybe just hold the top of the flange on the edge of your surface plate
so part of the flange rests on the plate and the taper portion hangs down,
and use your height gauge on the top of the tool to set the height.

If nothing else you could set up the DTI and check a couple of holders to
see how reproducible the flange location is. Oh, and manually rotate the
spindle to see how square and flat the top of the flange is. I've never
seen this done, but you asked for ideas :-).

--
Regards,
Carl Ijames