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[email protected] etpm@whidbey.com is offline
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Default ISO20 Taper Measuring Fixture

On Sun, 10 Nov 2019 19:47:01 -0700, Bob La Londe
wrote:

On 11/8/2019 5:43 PM, Bob La Londe wrote:
On 11/7/2019 6:56 PM, Bob La Londe wrote:
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.


I ran across this old thread on Practical Machinist:

https://www.practicalmachinist.com/v...-taper-232446/


It gives me the impression that I should be able to turn a fixture for
measuring tool height "good enough" even at my modest skill level on
the lathe.



Well, I made a fixture to hold the tool holders to measure.* Now I need
to make up a physical tool zero reference tool.

I turned a center in the three jaw.* Then I mounted a tool holder
between centers.* An indicator mounted in a lathe tool holder made it
pretty much dead easy to measure rise over run with the saddle.* I did a
little math, looked at the protractor on the compound, and set it by eye.

I had to check it three times.* The compound isn't all that smooth.* I
probably should take it apart, stone it, and then put it back together a
little tighter than it is. I didn't have to check it three times because
it was off.* I had to check it three times because it was dead on first
try.* The needle jumped a bit due to the import quality of the compound,
but the average from end to end was nearly perfect. I was using a half
though indicator.* It was bouncing less than two lines, and settled in
the middle when ever I stopped moving.

Turning the fixture itself was planned to do all important cuts in the
first setup.* Cut the taper and the reference surface on the bottom.
Everything else was unimportant.* I used a piece of stock that already
had a small hole in it big enough for the bottom of the tool taper and
the pull stud.* I face it off, turned the taper with the compound, and
then made a clearance cut below the planned bottom/base of the fixture.

I had it mounted pretty close to the chuck.* A regular left hand tool
wouldn't fit in the space I had available so I used a carbide insert
parting tool.* I opened up the clearance cut and angled the parting tool
slightly away from the chuck.* It has side side clearance on the insert,
but I wanted to make sure I could use it to make a nice clean draw cut
out of the slot to square up a ring on the bottom of the fixture.* After
I was happy I parted it off and turned it around in the chuck.

With the work piece mounted bottom out I turned a recess in the bottom
leaving just a narrow ring around the outside for it to rest on.

The tool holders set down in the fixture on their taper and don't wobble
even a little. If I press them in hard there is just the tiniest amount
of stick when I pull them out.* They feel solid in the hole.* I don't
know if the taper is a match, but as long as its perpendicular to the
bottom I think it will be good enough.

I did everything I know how to do to make the fixture.* Tomorrow I'll
test it on the surface plate with real tools in the taper.* Then I'll
make some cuts with them and see what happens.

I'm not going to blue it and check it.* I don't care if its a perfect
taper.* I just care that the tools seat to a consistent depth and pretty
close to perpendicular with the base.




I wasn't going to test it for fit up since that's not really what its
for, but I couldn't help myself. I wiped the taper of my new "tool
zero" with write erase marker, and dropped it into the fixture. I held
it in firmly and gave it a spin. About 90% of the marker was wiped off.

I love it when that happens.
Eric