Diy Brushless Spindle

[blackburn mark]

My intent is primarily to machine aluminum and hard plastics. I'm designing for 500-4000 RPM with hefty torque to use with 3-12mm end mills.

Anybody have an idea if these type motors will deliver decent torque at 500 RPM?

Adam

i dont cut with a 12mm endmill however i do cut a lot of acetal/delrin and a bit of alli with the larger of these spindles(250kv) 2.5mm to 6mm + fly cuting without any major problems, i personally believe you would struggle to make use of any more low speed power/tourque without having your gantry shake rattle n roll

thats asuming your going to run it on a router ?

i just had a look at where you live to see if it was worth nipping over to you so you could try one :lol: san francisco !!! thats a looooooong way LOL sorry man

[blackburn mark]

Well bought the motor today, got a 320kV one http://www.giantcod.co.uk/xyh5065-32...-p-404606.html so hope to have that early next week! Still waiting for my bearings from the US, been over a month now :-(

Still will give me a chance to finish off the bearing housing!

that looks a much better choice motor than i made for my C8 spindle... i think mine is 980kv

[njhussey]

Well got the motor today

Flipping bearings still have not arrived....think they've bneen lost in transit as now 5 weeks... still the seller said they'd expedite another shipment...

Mark,

did you put a groove in the ER collet shaft for the circlip or not?

[Villacherman]

Mark,

Well I will be over in your timezone in December for a couple weeks visiting wife's family, I suspect Newcastle isn't all that close to you all, however.

Thanks for the input, yes it will be a gantry router type design. I have a minimill that I'm making parts on and that's relatively low RPMs (up to 2000).

What RPM do you use the flycutter at?

Neil- maybe me bringing the bearings over and sending them through you post system would be faster! Any other parts hard to get there? Belleville washers?

Adam

[njhussey]

Neil- maybe me bringing the bearings over and sending them through you post system would be faster! Any other parts hard to get there? Belleville washers?

Adam

It can't be any slower Adam!!! Thing is I want these as they are 22mm OD which is better as the motor mounting bolt holes are 3mm dia on a 30mm PCD which only leaves 2.5mm wall thickness.

Belleville washers are ok, I've found a couple of suppliers and Mark kindly said he'd give me enough if I was struggling!

Gonna crack on with the bearing housing now and wait for the bearings...

[blackburn mark]

did you put a groove in the ER collet shaft for the circlip or not?

no.... my thoughts where that the tight fit (bearings n housing) would hold it all in place, iv had no problems so far using the double row a/c... i did have an issue with one my C8 spindle bearings (cheap skate bearings/bad fit on the shaft) resonating the inner race around the shaft at certain speeds so i used a bit of epoxy on that and its been ok so far.... now i think about it i guess the bellville washers become redundant once the glue has set and when the bearings wear i might get some slop ... it may need some further thought

What RPM do you use the flycutter at?

hi adam... iv not measured rpm's for a while however im pretty sure i skim acetal at 1500rpm and aluminium at less (maybe 1000rpm) thats with a 30mm radius fly cutter

with aluminium i have to be pretty careful (light cuts) or i get resonance patterns but im pretty certain thats my gantry sides and not my spindle

i should really do a test to see how low i can take the rpm and still cut with the fly cutter but iv never seen the need as iv allways got by at those speeds

[njhussey]

Dissassembled the motor, worryingly there was no locktite on the grub screw holding the body onto the shaft....needless to say there will be when it goes on the collet :naughty:

Am ashamed to say that for the first housing I'm cheating and getting someone else to machine the housing as they have offered to do it for nothing (our local machinist we use at work) in between jobs they are currently doing...which is very nice of them. I'll use the other bits I've started to do a smaller high speed spindle for engraving

At some stage I'll re-wind it as the winding is poor and also the potting/epoxying of the magnets wasn't too clever either as some was proud and was rubbing on the armature. Still you get what you pay for so I shouldn't be too surprised I guess...

[Villacherman]

Neil,

Does the rewinding take much effort? That's to change the v/RPM?

I'm waiting to see how things go with yours to start mine, looking forward to it! :)

Adam

[njhussey]

Adam, I don't know how much effort it will take. I'll do it to tidy up the winding (see photos) as it's not very neat but will not bother at first as I want to get the spindle up and running first!

[Jonathan]

You'll find lots of info on rewinding this type of motor on the rcgroups forum. If it works fine I wouldn't worry ... but if you want to change the number of turns to get optimal kv then it's got to be the way to go.

I wouldn't say you've got what you paid for when you paid more than the going rate for that motor:

http://www.hobbyking.com/hobbyking/s...idProduct=4913

I've not had any from hobbyking with poor magnet potting...but I've only bought about 10 and not the one you got.