"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?

--
Regards,
Carl Ijames