On 11/7/2019 4:48 PM, David Billington wrote:
On 07/11/2019 23:04, Jim Wilkins wrote:
"Bob La Londe" wrote in message
...
On 11/7/2019 8:09 AM, Bob La Londe wrote:

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.

Could you set up a dial indicator to read the flange in the spindle,
then run all your sockets thru and record the variation?

Instead of machining a socket you could cast one.
https://www.amazon.com/RotoMetals-Lo.../dp/B001QUVQE2


Clamp two tool holders on opposite ends of a shaft to fixture the
lower one exactly upright in the mold.


Might be an idea but check the characteristics of the alloy being used
as not all are dimensionally stable, IIRC some actually shrink slightly
after a time to allow for removal and gauging of holes. Also I have
Bendalloy and it is recommended to coat the tube internally with oil to
prevent sticking to the tube so the release film thickness might be an
issue.



Also, most of the low melt alloys I have looked at are pretty soft.