Back to Ganoksin | FAQ | Contact

High speed spindle


#1

I have a Taig micro mill, thinking of upgrading to a high speed
spindle (for wax). I dont want to spend thousands on an NSK for
example. I was looking at the Proxxon IB/E professional grinder,
which will do 20,000, with a runout of 0.001". I also saw some air
powered spindles on Ebay, but aren’t they noisy? Does anyone have
any suggestions?

Todd Welti
Living Color Opal and Intarsia


#2
I have a Taig micro mill, thinking of upgrading to a high speed
spindle (for wax). I don't want to spend thousands 

Harbor Freight has a 1/8" Air Micro Die Grinder ITEM 47869-4VGA
online for $9.99 that is rated at 0-56,000 rpm. And for less than 10
dollars they make a great high speed spindle.

Hans Stangier
Building a 1/8 scale Atlantic Steam locomotive


#3

Hi Todd,

I have retrofitted my Roland MDX-20 with a Proxxon LB/E 28485 and
could not be more pleased. Quiet, powerful and accurate. I run it at
about 12-13000 rpm, it tends to melt the wax if you go too fast but
it is easy to adjust.

There is also who has an e-Bay shop with high precision
spindles that are good.

regards Tim Blades.


#4

I have a Proxxon IB/E for a spindle on my Taig mill. It works very
well for wax and doesn’t make much noise. I also have a dental sized
air hand piece, very high speed (50K + ??) It makes the most
annoying high pitch whine which is not masked by the racket of the
compressor. And the compressor is in an attached insulated dog house.
Air tools also really suck air, check out the air consumption (double
this optimistic sales number) and needed pressure. Approach air tools
with caution, OK for brief jobs but not 10 hour overnight runs.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#5

Hi Todd,

I was looking at the Proxxon IB/E professional grinder, which will
do 20,000, with a runout of 0.001". I also saw some air powered
spindles on Ebay, but aren't they noisy? Does anyone have any
suggestions? 

I’ve got a Proxxon IB/E. It lives up to it’s reputation. It’s quiet,
well balanced & long lived.

It’s nose has a 20 mm ( little over 3/4") diameter collar about 11
mm ( little under 1/2") long for clamping in a mounting fixture or
some other machine. The on/off switch is separate from the speed
control.

Dave


#6

Hi Hans,

Harbor Freight has a 1/8" Air Micro Die Grinder ITEM 47869-4VGA
online for $9.99 that is rated at 0-56,000 rpm. 

The only problem with an air grinder is the requirement for an air
compressor to provide the compressed air to run the grinder. It’s a
good thing to look at both the air pressure & cubic feet per minute
required by the grinder to make sure your compressor can produce that
much ar & at the required pressure.

Dave


#7

I have retrofitted my Roland MDX-20 with a Proxxon LB/E 28485 and
could not be more pleased. Quiet, powerful and accurate. I run it at
about 12-13000 rpm, it tends to melt the wax if you go too fast but
it is easy to adjust.

I’d love to see a picture of that. I have a Roland MDX-15 and it does
what I need but I DO keep hearing about a better spindle.

Thanks - Justine


#8

I’ve heard that those Proxxon spindles aren’t suitable for long duty
cycles; they have a thermal cutout that will shut them off when they
get hot (which may not be when the part is done). Air powered
spindles are good for high RPMs and they don’t get hot, but they do
consume a lot of air. Having a 5 hp compressor going on and off
constantly really runs up the power bills; it seems silly to do this
for a tiny little tool. The spindles aren’t especially noisy, but the
compressor makes up for it. The NSK spindles are pretty nice, and
they’re pretty quiet, but they are expensive. If you want to keep it
inexpensive, a small electric wood router or laminate trimmer is
probably your best bet; they are rather noisy, but they’re cheap…

Andrew Werby
www.computersculpture.com


#9

Todd,

I’d stay away from air spindles. Noisy and you’d need a continuous
supply of clean, dry air which isn’t always easy to supply.

Proxxons are used somewhat in milling machines, and they work, but I
don’t think they are the best solution. The runout is fair and they
aren’t really designed for continous use although for a hundred
bucks, they’ll do a decent job.

You can also swap out the stock spindle in your Taig to a higher
speed, greater accuracy one like these:

ebay link removed. please no ebay links on Orchid !!

Either use the stock motor as is, increase the speed by changing the
pulley setup or swap it with a DC motor and speed control. You can
buy DC scooter motors cheap on Ebay with a control.

You might not need to go to 20K anyway if you’re milling wax, I run
my NSK at 12K, it gives a better finish than at 20.

Harry


#10

Hi Justine,

I'd love to see a picture of that. I have a Roland MDX-15 and it
does what I need 

I put my system together myself, but itis easier to get it from
http://fourth-axis.com/motor-mount

they do an external controller as well
http://fourth-axis.com/external-spindle-controller

Chris Cheer posts here sometimes( Hi Chris!!) he will tell you all
about it, he works for them, its not very complicated so he should be
able to cope

regards Tim Blades.


#11
I have retrofitted my Roland MDX-20 with a Proxxon LB/E 28485 and
could not be more pleased. Quiet, powerful and accurate. I run it
at about 12-13000 rpm, it tends to melt the wax if you go too fast
but it is easy to adjust. 

I hadn’t htought about the wax metlting. The Taig I have does 11,000
RPM. I had though that I could go to 20,000. I understand the
potential benefits of a higher RPM are:

Can move the endmill faster for a given chip load (does "chip load"
even apply to a profiler on wax?!?) Easier to vary speed (instead of
existing pulleys) Perhaps a cleaner finish… ?

But will i melt the wax? I use a .004 or .007 profiler, and purple
wax (though thinking about green).


#12

Hi Andrew,

I've heard that those Proxxon spindles aren't suitable for long
duty cycles; they have a thermal cutout that will shut them off
when they get hot (which may not be when the part is done). 

I conducted a little test with my Proxxon IBE.

Since I didn’t have anything to mill, I placed a slip mandrel in the
collect with strip of 3/4" (20 mm) wide abrasive paper about 4" long
(2" sticking out each side). I turned the IBE on to it’s highest
sped (20,000 rpm) & let it fan the air for about 3 hours. Admittedly,
fanning the air may not be as big a load as a milling project, but
the IBE was still going strong after 3 hr.

The motor housing was still cool to the touch but the spindle
housing was slightly warm to the touch.

Dave


#13

Todd,

Running your spindle at 20K will produce wax dust instead of cutting
a clean chip, the kinetic energy involved with recutting the chips
into dust will slightly melt it and make it pack it into crevices
and can remelt it on the surface. “Melting” is a misleading term,
it’s not like it melts into a blob, it just tends to slightly stick
to the surface. I use coolant, which helps by removing the chips and
prevents remelting.

So, 20K will not give you a better finish than 11K, you could run a
slightly higher feed rate if your mills up to it, but that won’t get
you a better finish either, just done faster. Chip load is low in
wax, you’ll break tips by too high a feedrate, not so much too low a
spidle speed. A superior surface finish is the combination of many
things, a rigid, accurate mill, an accurate spindle, cleanly ground
cutters and the proper feed and speeds. Fixing one doesn’t
necessarily fix the others.

Changing speeds is obviously easier with an electronic control than
pulleys, the other advantage is it’s a lot more accurate. I’m always
suspicious of the speeds rated by the manufacturer for pulley
systems, I think they’re a little optimistic. It’s worth doing the
math and figuring it out for real.


#14

I’ve run my Proxxon spindle many times for up to 10 hours on wax
(10K - 20K) without any heat problems. Also no signs of the (blue)
wax melting even using cutters which a scrape rather than shearcut,
maximum feed rate used.

Proxxan spindles will die if a crash causes them to stall for hours,
don’t ask how I know.But I didn’t hesitate to quickly buy a
replacement. For anything much tougher than wax they are pretty
wimpy.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#15
A superior surface finish is the combination of many things, a
rigid, accurate mill, an accurate spindle, cleanly ground cutters
and the proper feed and speeds. Fixing one doesn't necessarily fix
the others. 

A related question then: would upgrading to an ER16 spindle be likely
to get me a better finish than the “stock” spindle my Taig came with?
I haven’t measured the runout yet on my existing spindle, I suppose I
will. My biggest problem has been bits of compacted wax in some
recesses of the model, where there are sharp corners particularly. I
have tried using the ‘Masterblaster’ high pressure water sprayer that
some people advocate (doesn’t work for me). I have tried ultrasound
(no good for this), toothbrush (with and without various mild wax
solvents), and a few other things. The best result so far is manually
cleaning with sharp instruments, very labour intensive. I think the
nex thing to try would be running the toolpath again, as some have
suggested. Perhaps a different wax (I’m using purple - perhaps try
green?).

Todd Welti
Living Color Opal and Intarsia


#16

Dave

Since I didn't have anything to mill, I placed a slip mandrel in
the collect with strip of 3/4" (20 mm) wide abrasive paper about 4"
long (2" sticking out each side). I turned the IBE on to it's
highest sped (20,000 rpm) & let it fan the air for about 3 hours.
Admittedly, fanning the air may not be as big a load as a milling
project, but the IBE was still going strong after 3 hr. The motor
housing was still cool to the touch but the spindle housing was
slightly warm to the touch. 

Thanks for doing the test, Dave. I was going on hearsay there, so
it’s good to get some reality on the situation. Cutting wax with a
small cutter shouldn’t be much more stressful than fanning air the
way you did, so it sounds like it could do that for 3 hours at a
stretch, anyway. Did you notice a thermal reset button on that tool?
My informant may have been talking about another model of Proxxon
spindle.

Andrew Werby
www.computersculpture.com


#17

Hi Andrew,

Thanks for doing the test, Dave. I was going on hearsay there, so
it's good to get some reality on the situation. Cutting wax with a
small cutter shouldn't be much more stressful than fanning air the
way you did, so it sounds like it could do that for 3 hours at a
stretch, anyway. Did you notice a thermal reset button on that
tool? My informant may have been talking about another model of
Proxxon spindle. 

I’ve got both the models of the Proxxon motor tool, the FBS & the
IBE professional model. Neither has a thermal reset button.

If I were going to use a motor tool for a milling project, I’d go
with the IBE model. It’s spindle is use ball bearings & is set in a
metal housing. They FBS model while using ball bearings is set in a
plastic housing like most motor tools on the market today. The IBE is
about 40% more expensive.

Dave


#18

Todd,

I believe that the ER16 spindle has less run out than the old one
but other than the difference in effective tool tip diameter I’m not
pulling out my wallet just yet. Step over and the actual interface
between the bit and the wax have always been my priorities. Finish
come from the tool tip.

Yes the compaction problem is no fun, and it’s probably not caused
by partial melting. I mill alumilite plastic resin which doesn’t melt
and have the same problems. For wax one trick which works is a very
slow drip feed of ~50/50 isopropyl alcohol and dish soap. Just enough
to make a frothy mess, an IV drip works well. I didn’t need an
enclosure just some containment. But it is really corrosive on HSS
tools, I never tried it with carbide.

One day I reached my limit and snapped over the dental pick work…
no little screen blaster would suffice, but a real pressure washer
from the local hardware store. Awkward to use, surprisingly almost
every wax survives with no damage, and it does a nice job cleaning
decks :slight_smile:

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#19

Todd,

A spindle with less runout will certainly help with the fuzzies but
it’s only part of the equation. I’d measure the runout on your
current spindle so you can compare with others.

Here’s some other suggestions that’ll help eliminate them:

Make sure your stepover isn’t too large for your cutter size.

Some people run a second pass, I don’t find it necessary just to get
rid of fuzzies. Sometimes, I’ll run a second at 90 degrees to the
first if I want a perfectly smooth surface.

Make sure you’re using a good cutter, I had a few once that had
terrible runout themselves.

Green wax has the most plastic and produces the toughest fuzzies, go
ahead and give it a try if you’d like, but purple should be fine.

Use lube; a water based cutting fluid helps reduce them, I use a
drip system, some people use a few drops of mineral or soy oil on
the wax before cutting.

Give that master blaster a try again, I use a similar gun and it’ll
give me perfectly clean waxes.

These topics have all been covered in depth at 3dcadjewelry.com if
you need more info or pics.

Harry


#20

For those who are interested in the Harbor Freight Micro Die Grinder
that Hans Stengier mentioned, I will remind you of my offer of one
year ago. Any of you who will make a contribution to Orchid, send me
your address and I will send you a pair of brass bushings which allow
you to use 1/16 and 3/32 inch burs in the 1/8 inch collet that comes
from Harbor Freight. NO CHARGE, JUST CONTRIBUTE AS MUCH AS YOU WISH.

Dr. Mac