Diy Brushless Spindle

[blackburn mark]

Iv added another diy brushless spindle to my growing collection and thought id post my adventures just in case anyone was in the market for a quiet spindle with low rev torque for cutting plastics and aluminium on a router

my large ER11 spindle has been a top notch work horse and has been the one I use 90% of the time, its taken some heavy abuse even on one occasion cutting two 30mm holes through 20mm of aluminium
with a hole saw... slow and painful but it got me there in the end

I have on occasion found the ER11 collets limit tooling choices e.g. dove tail/t-slot cutters, thread mills and slit saw arbours tend to have shaft diameters larger than the ER11 capacity of 7mm

Iv managed to procure myself an ER20 C10 collet shaft sooooooo.... I hope to replicate the success of the first spindle with a few minor mods and the ER20 (up to 13mm capacity)

its still a really simple design, the original has one 3200 double row angular contact bearing in the nose, this one will have two 3200 double row angular contacts aprox 10mm apart in the nose and should stop any of the standard motor bearing slop transmitting to the tool end of things.... in reality I cant imagine ill see a difference as the MK 1 spindle works pretty well but I might as well, the theory is there and the bearings are cheep :)

it amazes me that more people have not built this type of spindle but I guess most of you are cutting wood but for anyone cutting plastics and aluminium on a router they make a lot of sense

this one I run on a 12v 350w power supply and get 2800rpm flat out and it maintains enough torque down in the mid hundreds(rpm) to deal with anything iv thrown at it... I know I have vastly under powered it but at 12v the speeds are good and the temperatures (motor windings/bearings and speed controller) remain sensible, besides that, any more power would be wasted on my machines inability to dampen the low frequency resonance.
6mm 4 flute carbide is about my limit when cutting aluminium and with a 60mm radius fly cutter ill get resonance patterns down wind of any holes I pass over unless I take it very easy
(errrrrrrr.... if any of that makes any sense)

£17:50 100A Brushless Motor Speed Controller RC BEC ESC (make sure you get the BEC version of any speed controller as it eliminates any need for a 5v supply to your servo tester/controller)
£17:09 C10 ER20 100L collet chuck CNC extention shank
£15:00 FOR TWO 3200/5200 DOUBLE ROW ANGULAR CONTACT BEARING 10X30X14
£ 1:89 New RC Helicopter Plane CCPM Servo ESC Checker Tester
£35:11 XYH63-54 250KV 65A Outrunner (excluding postage... cant remember)

(there is a cheep as chips outrunner on ebay for £16:60 delivered
"Outrunner Motor C6364 KV230 Brushless for RC Airplane"
but the one I got was very poorly balanced, the bell was out of true
by a degree or so and I didn't want to bother my arse trying to square it up)

£86:59 (ish) + some elbow grease a couple of lumps of ally and a 12v power supply

in order to get the second bearing pocket square with the first I milled it out under size fitted the first bearing and the ER20 chuck and put the whole assembly in the lath and skimmed the last 0.5mm with a small boring tool then skimmed the outer body to 43mm... worked a treat, all nice and square :)

Attachment 4597Attachment 4596



removing the exsiting spindle shaft can be a pain but this one came out pretty easy

cut one of the bearing recesses to a press fit and you should be able to part assemble
your spindle and skim the second bearing recess to an almost perfect alignment


the ring with the six holes is there to extend the clamping aria to make it compatible with my exsisting spindle clamp and is not esential (it will help keep the crap out though and looks posh)



part assembled again to skim out where the bearing housing sits to a tight true fit


servo controller and 100A ESP



almost finished.... just needs some drilling and tapping to lock the bearing housing to the acetal mount and were off


looking at this photo has me thinking im developing a bit of a fetish for these brushless motors :twisted:
the blue motor is the "cheep" one that has an extreamly out of balance bell, also in my rush to get it finished i managed to take to much material off the bearing body and had to use aluminum tape to shim it out to fit my clamp its seen me though a couple of tight spots though and will now be retired as a spare

the small one will run up to a theoretical 48000rpm on 12v but i cant see the bearings lasting long at that speed, i keep daring myself to test it to destruction but i just cant bring myself to do it and i get by with it running below 20000rpm
the yellow one will run upto 10000rpm and i tend to use that for tool grinding



exsample of some of the work done with these spindles... i love cutting acetal and i love thread milling M3 in acetal, if things go awry you tend not to snap the tool....
thread milling should be re classified as an extream sport.... its WELL exciting ... or is that just me being sad ?

[Rogue]

Interesting and intriguing!

[Jonathan]

The thing to do with your collection of spindles is index them ... rotary table on the Z-axis with the spindles each mounted 72° apart then just spin it to the one you want - like on a CNC lathe. That basically gets you an automatic tool changer. The only potentially difficult bit is locking the rotary table automatically...and maybe the wiring! Hmm you've given me a project now, as if I didn't have enough to make! Use some sort of rotary switch, or just 5 microswitches to activate each spindle automatically. Even snazzier is if the motors are similar you can use one ESC for the lot, and a bunch of relays to switch between spindles...

I should probably use mine more now I'm almost invariably cutting aluminium on my router. It's only 6000rpm (allegedly 6kW) though which is about half what I'd like...





How much difference do you think using the two double row bearings made versus one? Mine has one double row and something like (can't remember) 5 standard bearings.

[Jonathan]

This motor looks like the same as what you used, and it's cheap:

http://www.hobbyking.com/hobbyking/s...idProduct=5144

I'm tempted to get at least 3 of them, plus one ESC, and mount them all along with my existing spindle.

http://www.ebay.co.uk/itm/C10-ER20-1...ht_1682wt_1037

Could get a bit expensive...

[blackburn mark]

The thing to do with your collection of spindles is index them ...

hahaha! yep it did cross my mind man but i tend to use the 2000W spindle for almost everything i do and changing spindles is a moment of a job

How much difference do you think using the two double row bearings made versus one? Mine has one double row and something like (can't remember) 5 standard bearings.

i havnt cut anything with the new one yet jonathan, i was well happy with the old one, i belive it could out perform my machine with the single double row in it but as i was building a new one it seemed silly not to add the second bearing if i could suss a way of keeping the resses perfectly true.... it was a nice surprise when i fitted the shaft and there wasnt any extra friction due to missalignment (its a tough nut to crack)

it will be interesing to see if there is any inprovement but im sure the resonance paterns i get are from my gantry sides

[blackburn mark]

This motor looks like the same as what you used, and it's cheap

NICE.... its a bit better than mine.... i must resist i must resist i must... you bugger jonathan!!!!! iv got enough brushless motors

the ER spindle you linked is the one i bought... took about three weeks to turn up but you cant go wrong at that money :)

[Jonathan]

hahaha! yep it did cross my mind man but i tend to use the 2000W spindle for almost everything i do and changing spindles is a moment of a job

So make more of those ... the prospect of not changing tools manually would be worth it for me. That and it'd look pretty awesome.

NICE.... its a bit better than mine.... i must resist i must resist i must... you bugger jonathan!!!!! iv got enough brushless motors

Resist that one and get this one, it's 280kV so a bit faster!

http://www.hobbyking.com/hobbyking/s...idProduct=2097

Looking forward to a video of the new one running...

[blackburn mark]

So make more of those ... the prospect of not changing tools manually would be worth it for me. That and it'd look pretty awesome.

i could murder you jonathan!!

the power and switching would be the easy part... just make interupted slip rings driven by one ESC

the tricky bit is making the capstan rigid without it weighing a ton and having a masive overhang

i dont believe youv got me thinking on this one... iv also got a million and one things going on "i must get some sleep at least once this week"

it would be nice to have a 5x tool change though i could go down the pub swill a couple cut the lawn smoke a couple have a manicure come home change slabs have a couple of hours sleep.............zzzzzzzzzzzzzzzzz............

i may ponder this some more but i can sniff a bit of a blind alley coming on

[njhussey]

Hi Guys...

I've just started to build my router again after a years lay off (got into RC Helis which I fly in B'burn which ate/eats up all my money and sparetime) and have a servo tester (for setting the CCPM swash on the heli up) and spare a few spare ESCs so this is looking interesting!! To start with I'm only looking to cut balsa and ply but as time goes on I'll want to cut plastic and maybe some Ali (when I've made mods to my router.) What would your suggestions be for motor etc? I was thinking of something a little smaller than yours, something like http://www.giantcod.co.uk/xyh5065-27...-p-404605.html with a http://www.ebay.co.uk/itm/C8-ER11-10...item2567df6da9 we have an old Colchester Bantam lathe at work so could have a go at the bearing housing...

Cheers, Neil.

[blackburn mark]

hi neil, sounds like youll have no problems with the project

id be tempted to go with an ER11 C8 with a little less overhang

http://www.ebay.co.uk/itm/ER11-8MM-S...item231507033b

if you compare this with the one you linked i think youll know what im driving at... it may make little diffrence when cutting balsa but when aiming to cut ali every little bit of stiffness you can gain will help (i have cut ali with mine)

iv used cheep skate bearing in my ER C8 spindle... iv used belleville washers to put some tention between the two outer races.... i havnt had to change them yet but it only gets light use

if you dont put any tension on those skate bearings the balls will skid and self destruct pretty quickly


the layout is not to clear in this picture, youll have to let me know if you dont get it