On Sat, 14 Feb 2015 22:24:36 -0600, Martin Eastburn
wrote:
On 2/14/2015 9:00 PM, Gunner Asch wrote:
On Fri, 13 Feb 2015 18:09:02 -0600, Karl Townsend
wrote:
I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.
Last year, I took the spindle apart and installed all new bearings -
no help.
I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.
Any suggestions on my next step here?
Karl
http://www.spsspindle.com/sps-spindl...le-rebuilding/
However...keep in mind that if they grind the spindle taper..your tool
may not..not fill the hole..so they will also have to grind the nose
of the spindle and depending on how much metal they removed..they may
have to recut the holes for the alignment blocks. Generally when
regrinding..they will remove between .015-.05...but...shrug
Have you put a tenths indicator on the spindle taper and find out how
much out of alignment is inside the taper? That is #1 task.
Its entirely possible to have poorly ground or worn tool
holders..which will show up as a bad spindle alignment.
So put a tenths indcator on a holder and check at the inside of the
beginning of the taper..then stick it inside with the longest probe
you have and measure as far inside as you can.
This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.
Gunner
It might be as simple as oil. Or as I found in Dad's lathe when I got it,
the chuck was running a bit off - and there was a chunk of swarf from
inside of the chuck - in the chuck threads. It was pressed on like
everything. The chuck wasn't sitting square. I was able to clean the
thread and clean the chuck for other junk. The chuck screwed onto
the spindle as it should and mounded square on it. The chuck was
back to the normal quality. It had baffled dad, but I think his
eyesight was going badly by then and he missed the smear of steel.
Martin
Good catch! I have both 30 and 40 Nmtb tooling for the Gorton
MasterMill and the Larios horizontal and I religiously run a
scotchbrite inside both spindle tapers a couple times a year. I
generally dont change my tool holders very often, I use
interchangeable collets inside the tool holders..but they get cleaned
regularly as well. Both have .0001 runout..I can live with that I
think...
My Hardinge HLV-H had some swarf in the tailstock taper that had been
mashed in pretty badly..so I borrowed a #2 MT finishing reamer and
just touched it off and now I use a bright flashlight to look inside
now and then. Couldnt figure out why my centerdrills were .015 to the
side and it was driving me nuts.
Gunner
"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke