RC Brushless spindle

[volcano]

Update:motor returned.
Looking for new one... 500-600kv.
Any suggestions?

[njhussey]

Update:motor returned.
Looking for new one... 500-600kv.
Any suggestions?

The kV of the motor you need will depend on the Voltage you're going to run it at and what you want to cut.

[volcano]

Hi, tnx for replay,
I want to cut a little of everything (alu, pom, mdf , some glass etching), (Glass isn`t obligatory - i can do it with my dremel tool @ 20000+ rpm). So... first alu , than acetal and mdf.
I know that`s hard to do with one motor, but hope it isn`t impossible.
Now as i`m not "bound" to previous motor specs, i would like to go "around" and start with psu i`ve got already- 12V30A. Read here that similar psu-s are already used - not for max motor efficiency , but still, for something useful.
I`ve heard that 24v cause hot motor ( and i have 24v@4-6A, only)
So if i go with this cheap psu what can i drive with it?
Some other suggestions?
Cheers!
P.S. They say that i can keep this 270kV. Any use of that thing (if it works- i have not tested it yet as i don`t have esc and servo tester yet)?

[njhussey]

The problem is with 12V and 270kV you'll only have max 3240 RPM which is from a practical point of view too low for Ali, Plastic and MDF, well technically it's not but the feeds will be very slow. With 24V yes you will have to think about cooling the motor (a couple of 12V PC Radiator fans in series mounted round the motor would do it) if you're doing long runs but you get better speed. I ran my spindle off 2 HP Server PSU's wired together to give 24V (and over 1000 Watts) and it was fine, but I didn't do many long runs and didn't use it in anger as I have a 2.2kW water cooled spindle which is fantastic! If I made one again I'd put water cooling in the bearing holder body as they do start to run hot after a while.

One suggestion is to make the spindle unit (don't over engineer it) and have the motor drive it by belt, if you make an adjustable motor mounting plate (or different ones you can swap over) then you can use different kV motors depending on what you want to cut, so larger lower kV motor for cutting Ali, MDF and Plastic and high kV smaller motor for engraving glass etc...

[volcano]

Thanks for your advices, as always. This means a lot for me in my future building. One thing is to just read topics... and completely different thing is when someone experienced push you in wright direction :-), as you all know.

It`s done. I order this:
http://www.ebay.com/itm/N5055-1450W-...QGNF7nYDNiv2jQ
The 270kv one, will wait for now (if it works, anyway). I`ll build belt driven spindle later, i hope.
For now, i want to build direct drive spindle, to be my first. :-)
I found those bearings:
http://www.ebay.com/itm/1Pcs-708AC-7...QAAOSwpP9Y7IHm
Are they good, or to go with cheapest ceramic skate bearings? ...or steel ones?
I asked this because i already gone on cheapest route ( motor, collet shank...esc...).
I need this answer as quick as possible ( because of shipping time )
Hope you`ll understand.
Cheers!

[volcano]

While waiting for motor,chuck,esc... to arrive, i`m thinking about hooking this spindle to arduino (grbl1.1 with pwm variable spindle controll).
Can this item be "in between" esc and arduino? Check it here please:
http://www.ebay.com/itm/Pulse-Signal...EAAOSw1S9We2se
If this can be used it would be great. By the way...if anyone here control esc with arduino with grbl, let me know, how, please?

[volcano]

Where are you folks? I started to feel that i wrote here for myself pleasure only!
Anyway, new build idea...
I think i`ll add 1 of those bearings in spindle nose and then add skate ones after.

I think that this will eliminate axial force on ("next in row") radial skate bearings.

P.S. I must construct proper housing for this combo.
Cheers!