Diy Brushless Spindle

[Villacherman]

Neil,

I like the design. Is there enough wall thickness of the collar (8mm ID X 10mm OD) to accommodate a small screw?

What about a collar that has a thicker wall and a little standoff, like this... gives you more meat to tap into.



This could also allow for a more tortured path on the bottom collar to keep dust out.

My last comment is to not forget to think about how you will assemble this... go through the steps in your mind, sometimes I design something and find out I can't assemble it because there are inaccessible features! :(

Adam

[Villacherman]

I just figured out grub screws are 4-40 set screws... I'm learning everyday!

Neil, was the shaft of the motor hard to swap out for the collet shank? Anything I should not do? I want to give it a try this weekend. I'll do all the usual, keep things straight and support, remove the circlip, etc...

[njhussey]

I just figured out grub screws are 4-40 set screws... I'm learning everyday!

I'd be using 2 off M2 x 3 grub screws and locktite in each collar (will prob make it 3mm thick for extra purchase of the grub screws) as per the attached photo.

Neil, was the shaft of the motor hard to swap out for the collet shank? Anything I should not do? I want to give it a try this weekend. I'll do all the usual, keep things straight and support, remove the circlip, etc...

I removed the circlip and pulled the bell off the motor complete with the shaft. Then put the bell on the vice so the shaft was between the jaws but the bell resting on top (obviously with a cloth on the jaws to stop marks) and using a 6mm piece of steel I had lying around gently tapped the shaft out of the bell (obviously remove the retaining grub screw first!!) slid out fine!

I've not put the collet shank in the housing properly yet (although I did fit it slightly on to see how it spum ) as I'm waiting to make the bearing housing first. Been far too busy at work this week to do any machining in my lunch but hoping to get it done next week. This weekend I'll be making my router gantry sides and trying to get that sorted although I keep changing my mind on how to do it!!

[rnr107]

Hi blackburn mark,
Looks very interesting concept! :-)
I just have 1 question so, How do you get the original shaft out of the motor?
Is it fitted with an interference fit to the bearings?

Ta,
RNR

[Villacherman]

Rnr107,

I just removed the shaft yesterday on my Turnigy G110 outrunner motor, so this is specific to my motor, others will vary...

1) remove the 4 M3 screws from the propeller mount.
2) remove the e-clip (circlip, retaining clip, however you want to call it) from the side of the motor with the shaft sticking out.
3) pull the shaft out by hand (I've heard you may need more force on other motors)

That's it! I really like the G110 for its simplicity in this manner, though it is a little pricier.

Adam

[njhussey]

Hi blackburn mark,
Looks very interesting concept! :-)
I just have 1 question so, How do you get the original shaft out of the motor?
Is it fitted with an interference fit to the bearings?

Ta,
RNR

Hi rnr...most are sliding fits but as with all Chinese mass produced manufacturing will vary from motor to motor...mine is a medium sliding fit :-)

[rnr107]

Thanks Adam , Neil! I think I will give it a go, It looks very interesting! :-)

Laurent

[paul.hunaban]

I want to change out my wood router for a brushless spindle as I’m having to replace the brushes all too often.
What you guys have done here is very interesting but I’m not sure how to size the motor / what motor to get.
Therefore I have a few questions:
Q1, if the RPM/v is rated at 295 does this mean for every volt it will increase by 295 revs, i.e. for 20v the speed would be 5,900 revs?

Q2, would you read the power output in the same context as you would a wood router, i.e. if both were 1000w would both be deemed to have the same output?

Q3, Any recommendations for motor to cut wood (Oak) ? At the moment I do a lot of 3D profile work thus cut at around 2.5m per min.

Q4, should I give any consideration to the speed control other than it meets the spec of the motor, ie is there a rule of thumb for the control to have say a 10% high power rating?

Many thanks in advance Paul

[Jonathan]

1) Yes that's right.

2) Hard to say - the ratings for the brushless motors are a bit optimistic since they assume excellent cooling from the very high airflow present in a model plane. What power rating the motor is will be dictated by the speed rating since 'hobby' brushless motors with a similar kv specification tend to have similar power ratings. That's unless you introduce a belt into the system...or couple multiple motors on one shaft, but that's probably taking it too far for machining wood.

3) Clearly depends on the tool diameter, but I'm guessing you'll want about 12000rpm for oak? So look for a motor with around that speed rating. Ideally you don't want to have to use 'high voltage' (i.e. above 25V) ESCs as they're very expensive. So roughly 12000rpm/25v=480kv, or more if run from a lower voltage...

http://www.hobbyking.com/hobbyking/s...ner_Motor.html

Your next problem is the shaft diameter - the one above is only 6mm which makes it a bit useless unless you have a lathe to modify/make a collet chuck...

5) Easier to advise once the motor is chosen, but it's sensible to get a bigger one than rated to be sure. They're pretty cheap from the site I linked to above.

[paul.hunaban]

Jonathon, thanks for the speedy reply.
I’ve just order from Hongkong the 100a motor control plus a drive module so that’s dealt with. I’m not too concerned about the shaft / collet holder / bearings as I will hand that off to my brother to sort (although he does not know it yet!) and he’s tooled up for the job.
As to the power supply, seems your suggesting a 24v, how about the amps? I’m not sure how the PWM supply to the motor is translated for the source.
Regards Paul