My Spindle Isn't Worn Out
 

My Spindle Isn't Worn Out
Collets are Consumable

For the last month or so I started noticing alignment pin holes that are
spiral interpolated on one of my machines were a little loose. Press fit pin
holes were getting to where I could press them in with my thumb. That's a
bad thing. Those little high speed spindles have a finite life and that one
is a year old. I don't think it has the 6000hrs advertised for the bearings,
but it might be getting close, and honestly I usually get more than 6000hrs
out of them Still to be that loose I thought I'd be able to "feel" slop in
them when the spindle was cold first thing in the morning. No slop. Ok, how
about a runout test. Not much. Much less than 1/2 thou. Maybe 2-3 tenths.
Now to be fair I did a runout test with a dowel pin in a 1/4 inch collet.
Then I set up the indicator to measure travel backlash in the table. Nope
still just a hair under half thou, and that would make smaller holes not
larger. Finally I looked at the little 1/8 inch collet that was holding the
1/8 SE mill that was making the oversize holes. Or rather I took a fresh new
one out of the package and cut a mold. Perfect. Everything is back to
normal. I have to use the arbor press to set pins again. That collet has
outlasted one spindle, has thousands of hours on this one, and has probably
pushed more than a couple small end mills to the breaking point. I guess I
can't complain about a very cheap Chinese ER16 collet. Collets are
consumable.

My Spindle Isn't Worn Out
 

"Bob La Londe" wrote in message
...
My Spindle Isn't Worn Out
Collets are Consumable

For the last month or so I started noticing alignment pin holes that
are spiral interpolated on one of my machines were a little loose.
Press fit pin holes were getting to where I could press them in with
my thumb. That's a bad thing. Those little high speed spindles have
a finite life and that one is a year old. I don't think it has the
6000hrs advertised for the bearings, but it might be getting close,
and honestly I usually get more than 6000hrs out of them Still to be
that loose I thought I'd be able to "feel" slop in them when the
spindle was cold first thing in the morning. No slop. Ok, how about
a runout test. Not much. Much less than 1/2 thou. Maybe 2-3 tenths.
Now to be fair I did a runout test with a dowel pin in a 1/4 inch
collet. Then I set up the indicator to measure travel backlash in
the table. Nope still just a hair under half thou, and that would
make smaller holes not larger. Finally I looked at the little 1/8
inch collet that was holding the 1/8 SE mill that was making the
oversize holes. Or rather I took a fresh new one out of the package
and cut a mold. Perfect. Everything is back to normal. I have to use
the arbor press to set pins again. That collet has outlasted one
spindle, has thousands of hours on this one, and has probably pushed
more than a couple small end mills to the breaking point. I guess I
can't complain about a very cheap Chinese ER16 collet. Collets are
consumable.

Did you measure the difference between the arbor press and thumb fit
interference?

My Spindle Isn't Worn Out
 

On 5/25/2019 4:11 PM, Jim Wilkins wrote:
"Bob La Londe" wrote in message
...
My Spindle Isn't Worn Out
Collets are Consumable

For the last month or so I started noticing alignment pin holes that
are spiral interpolated on one of my machines were a little loose.
Press fit pin holes were getting to where I could press them in with
my thumb. That's a bad thing. Those little high speed spindles have
a finite life and that one is a year old. I don't think it has the
6000hrs advertised for the bearings, but it might be getting close,
and honestly I usually get more than 6000hrs out of them Still to be
that loose I thought I'd be able to "feel" slop in them when the
spindle was cold first thing in the morning. No slop. Ok, how about
a runout test. Not much. Much less than 1/2 thou. Maybe 2-3 tenths.
Now to be fair I did a runout test with a dowel pin in a 1/4 inch
collet. Then I set up the indicator to measure travel backlash in
the table. Nope still just a hair under half thou, and that would
make smaller holes not larger. Finally I looked at the little 1/8
inch collet that was holding the 1/8 SE mill that was making the
oversize holes. Or rather I took a fresh new one out of the package
and cut a mold. Perfect. Everything is back to normal. I have to use
the arbor press to set pins again. That collet has outlasted one
spindle, has thousands of hours on this one, and has probably pushed
more than a couple small end mills to the breaking point. I guess I
can't complain about a very cheap Chinese ER16 collet. Collets are
consumable.

Did you measure the difference between the arbor press and thumb fit
interference?




Nope. But I know what its supposed to feel like when I press it in with
the press and it feels right. There is actually a lead in I machine in
the holes to make sure the pin starts straight that has always dragged
lightly and its back to that feel too.