[Jay C]

Also, car batteries would be overkill. In fact say you want 30 watts to etch PCB, then you only need 30/22 = 1.4A. These motors are very efficient at around 80-90%. These motors can go up to tens of amps. There is a direct relationship of current to torque. Also, the faster you spin (voltage), the faster the windings reverse direction, the faster your core loses start to heat the stator. You should include forced air cooling and make sure the fan/prop whatever is well balanced.

I'm close to trying this, but the Colt is so simple to use and I don't need < 16mil traces at this time

[NEATman]

CHUCK99Z28-
You mentioned that you have ~$500 to spend...

You can watch Ebay for a Precise Spindle - I have a 1/2 HP model that has a 1/8" collet, and spins to 45,000 RPM.

Something like this would be more that adequate:
http://cgi.ebay.com/Nice-PRECISE-35-...item5ad79878bf

You could also try one of these:
http://cgi.ebay.com/0-8-KW-CNC-route...item2a07f5cfde

I believe that there is a whole thread on this type of chinese spindle here on CNCzone.
Keith

[Drools]

here is another question I forgot to ask. Would Mach3 be able to control the motor via the ESC?
What am I thinking! that would be too easy, there must be some extra electronics involved to make the connection from Mach3&parallel port or BoB to the ESC...

[Jay C]

here is another question I forgot to ask. Would Mach3 be able to control the motor via the ESC?
What am I thinking! that would be too easy, there must be some extra electronics involved to make the connection from Mach3&parallel port or BoB to the ESC...

If I'm not mistaken Mach3 uses PWM to control speed. The ESC uses RC servo PWM which is different. The Mach 3 output is a square wave at some fixed frequency (say 8KHz). The On time divided by the total time (1/Frequency) is the duty cycle.

The RC servo signal expects a train of pulses between 1ms and 2ms in duration repeated every 30ms.

You would need a simple micro (like the AVR Tiny13) to read the input and output the control signal. Also most ESC's have auto programming which means you need to "blip" the throttle to full to set the high end and try to map the output linearly to the RC signal.

You find me the Mach3 specs on the output PWM, and I can help create a control interface ... deal? The M3 PWN could be converted to analog and read in via A2D too.

-Jay

[Jay C]

Nevermind, found it.
http://www.cncathome.com/vfd.html

You can specify your own base frequency and the output is 0 to 5V.

[veteq]

For around 500 dollar you could buy a NSK NR-303 spindle with collet and a rc brushless motor with controller (hobbywing).

Only thing you have to do is make a adapter between the 2.

Then you have a spindle with a runout off less than 0,00004 inch.....

[Herbertkabi]

hi NEATman,
do it yourself - this is hobby, does not matter is it cheap or not ... sometimes even cheap.
Why thousands of members in this forum are building machines when better to buy? Why they cutting, milling turning ... you can buy all or order from real shops? Because this is hobby!
Yes, this is seroius illness but much more better than alcoholism, drugs or just aineantise, rant and rave


About actual rc outerrunner motors I see you like to try:
Come on, guys! You choiced gigant ones! Looks like for ER25 and bigger.
Too large rotor diameter for tiny endmills.
Look at my spindles from other threads I have added draws and pdotos.
Hereby one video where speed has been reduced for saving my EOS camera:
http://helicam.ee/cnc/CNC1.mov
I use 10.000 rpm ... 30.000 rpm (6mm ... 1.6mm endmills).
also see Voltage and Ampers
Cheers,
Herbert

[NEATman]

Herbert-
I understand this is a DIY hobby - I bought the Precise spindle for $50. I have it clamped to the quill of my converted 3 axis bridgeport mill for milling circuit boards and tiny parts. I checked into getting a couple different collet sizes and they are $115 each from the factory! Luckily it came with an 1/8" collet.

Also, I was responding back to Chuck, who started the thread, and he stated he was willing to spend $500 for a decent spindle. I was just trying to state that there are deals available for some excellent high speed spindles.

Also, if I wanted an insanely accurate high speed spindle, I would make an air bearing spindle - they have runouts of about 1 millionth of an inch or better, with almost zero friction. I have designed many of them for the disk-drive industry.

I do have to admit, the out-runner motor with a collet extension is a very clever DIY spindle idea.

Keep the ideas coming!

Keith

[Herbertkabi]

hi NEATman,
out-runner motor I do use only when lower rpm and higher torque ... and when need to keep the shaft when manual tool changing (my Sherline conversion). Mostly I build motors myself but sometimes I use existing RC motors as well - then I buy very cheap from eBay, even weared out or crashed ones because in any case I do rebuild it, bearings need to be changed anyway, even when new rc motor, and to rewind any rc motor ... this is doit for me even with closed eyes.
I have three Precise spindles, one near new, one totally weared, bought just for study, and one with cooked motor, this one I rebuilt to brushless.
Air bearings ... ??? ... yeah, in real life this is useless. Two years ago I bought one unit from eBay, nice thing, but where to use 100k ... 200k rpm and super-micro-machining - at least my cnc does not allow for this kind on precision. "Normal milling" will destroy this spindle in few seconds.
I dont need to machine such kind of parts what I cant see with my own eyes
regards,
herbert

PS:
When to use rc motors and esc then besides of heli (governor) mode is clever to use different Voltages because governor keeps rpm the best in fairly narrow area of. Switch mode power supplies are OK, even China made.
And esc-s are very different, some are better, somes want to go too hot even when right settings and 2...5A current (normal amperage for ER11 size 24v , 10...20k rpm DIY spindle).
China made slotless brushless motors are also OK for spindles but ONLY with water cooling. Motor KV is important! KV-1000 = 24k RPM max when 24V (12k RPM max when 12V).

[chuck99z28]

Wow, this thread is really helping me out.
Thanks for all the input and responses.

[chuck99z28]

Neatman,
Thanks.
In fact, that what got be started on this whole thread.
I really appreciate your input.

CHUCK99Z28-
You mentioned that you have ~$500 to spend...

You can watch Ebay for a Precise Spindle - I have a 1/2 HP model that has a 1/8" collet, and spins to 45,000 RPM.

Something like this would be more that adequate:
http://cgi.ebay.com/Nice-PRECISE-35-...item5ad79878bf

You could also try one of these:
http://cgi.ebay.com/0-8-KW-CNC-route...item2a07f5cfde

I believe that there is a whole thread on this type of chinese spindle here on CNCzone.
Keith

[chuck99z28]

Michael Hammer is the guy who cast and build the one in the rcgroups thread. The thread is all about the build of his router.
I took the easy way out and bought a 75mm diameter round extrusion 150mm long. It only cost A$20 which included the cutting charge. Will get two housings and so left over out of that and much simpler then casting one. Will have to try some casting one day.
I have access to large lathe and mill at work so it will be an afterhours project.
Still waiting for my motor and ESC to arrive. Been two weeks now which means it is lost somewhere. HK to Aus is normally a week, max.
I have attached two designs. A square one which will easily bolt to the Z and a round one that can be mounted in an existing router mount.

Gareth

Gareth,
Can you provide some details on which/where your found the extrusion and which collet chuck you are are using?

Did you actually get this to milling yet?

[ghassall]

The Aluminium that I am using is 50mm x 50mm x 6mm
Some 2" X 2"x 1/4" would work fine.

I haven't cut anything with it yet. I have drilled a couple of holes. I have my trim router mounted at the moment. I think for cutting MDF the angle bracket has too much flex in it. Need to do some more testing.

I also noticed that near full speed on 12V it is extremely loud, it has a resonance issue or something like that. I did some testing with a 20V power supply and once you past this point then it becomes very silent. Just the whirl of the bell through the air.
For PCBs and fine engraving it will work well. May need to shorten the shaft to the reduce whip and loading on the top bearing.
If I did it again I would buy an ESC with governor mode. This will regulate the speed better under load.

This one would be my choice. Will handle up to 36V.
http://www.hobbyking.com/hobbyking/s..._Brushless_ESC
You will need a programming card and maybe a servo tester to control it.

If you want to go nuts with a motor then the Scorpion's look good.
http://www.scorpionsystem.com/catalo...s/hk40/?page=1
All the HK40 series run a 8mm shaft. Some have the ends turned down to 5 or 6mm for the pinions. If you look at the specs some put out a serious amount of power and can handle a lot of abuse. Also they use 1608 bearings in both ends. Where as the Turnigy one that i am using has a 1608 in one end and two smaller 8mm ID bearings in the other.
Also the build quality of the Scorpion's is much higher.

Here is a link to the chuck and collets.
http://www.ctctools.biz/servlet/the-159/ER11-COLLET-CHUCK-8MM/Detail
http://www.ctctools.biz/servlet/the-...ets/Categories
Also do a search on ebay for ER11, sometimes they come up cheap.

Once I use my spindle a bit more I will post some more info.

Gareth

[ghassall]

You can even wind your own motor!
http://www.scorpionsystem.com/catalo...its/hk40_kits/

Hmmm. That's go me thinking. Buy the kit. Ditch the center bearing holder and make this part of the lower bearing assembly. Will whip something up in Solidworks and post it later.

[ghassall]

Here is the design.
Notice that the top bearing is not pressed in the main body. It presses into the stator pack as per the Scorpion build instructions.

I was thinking of pressing the stator off my Turnigy and doing this sort of thing. Still might, but am a bit worried about damaging the windings. If I do I will have to re-wire it.

[Herbertkabi]

hi,
Good spindle bearings for affordable price:
Super Precision Bearings.
Fag FAG B71903 C.T.P4S.UL FAG
grease 48 000, oil 70 000 RPM,
17 x 30 x 7 mm,
http://shop.ebay.de/weichesfell/m.ht...&_trksid=p4340
two weeks ago I bought 5 per EUR 20 with shipping,


cheers,
herbert