Tool Post Grinder

[whydontu]

Is that the same motor? The Amazon link shows an output shaft (presumably running through bearings) & separate ER 'collar' mounted on shaft retained by set screw.
But your disassemble pic looks like an integral ER shaft running through motor housing/bearing(s)

View attachment 42383View attachment 42387

I should have been more careful in my selection of Amazon offerings. The motor and controller I bought has a solid shaft with the ER11 collet socket machined directly into the shaft.
Some if the specs are BS, maximum RPM is 12,000, and actual current draw is more like 100 watt at 48 volt. But it is very smooth and quiet and is a massive improvement over the original brushed 24v spindle I had.

https://www.amazon.ca/RATTMMOTOR-Brushless-12000RPM-Controller-Switching/dp/B0B11R2Q7T/ref=sr_1_9?crid=30FF6XAUF9UAI&keywords=bldc+spindle&qid=1704133010&sprefix=bldc+spindle%2Caps%2C201&sr=8-9&ufe=app_do%3Aamzn1.fos.d0e27fc4-6417-4b26-97cb-f959a9930752

 

[PeterT]

Yup, that's why I was asking. The integrated ER shaft brushless model you show seems to be a step up in a few respects & seems to get better reviews with a few mini CNC posts I've read (but I have no firsthand experience with). Probably why it costs more too. Yes the power specs are bogus & I've very suspicious of stated runout too. I'm contemplating the same one, so keep us posted how it runs. Heat is the enemy on these & despite seeing some teardowns, I can't see if they have any temperature compensation meaning floating (typically rear) bearing assembly. Maybe mini CNC guys just know how not to push them, but grinding can be a power consumer even with innocent looking material removal rate, so something to be aware of.

 

[whydontu]

Yup, that's why I was asking. The integrated ER shaft brushless model you show seems to be a step up in a few respects & seems to get better reviews with a few mini CNC posts I've read (but I have no firsthand experience with). Probably why it costs more too. Yes the power specs are bogus & I've very suspicious of stated runout too. I'm contemplating the same one, so keep us posted how it runs. Heat is the enemy on these & despite seeing some teardowns, I can't see if they have any temperature compensation meaning floating (typically rear) bearing assembly. Maybe mini CNC guys just know how not to push them, but grinding can be a power consumer even with innocent looking material removal rate, so something to be aware of.

My no-load runout is perfectly acceptable. Video at https://canadianhobbymetalworkers.com/threads/new-cnc-engraver-spindle.9344/#post-137483

I didn’t pull the rear bearing, but the front bearing is live loaded with a wave washer.

Might be a bit before I try the motor as a tool post grinder, project #42c.

 

[Proxule]

Hey sus. You ever stumble on some stones you like ?

Thanks

 

[Susquatch]

Hey sus. You ever stumble on some stones you like ?

Thanks

I've bought a few now (Ali & Amazon) and although they all work, I didn't fall in love with any of them. Certainly not enough to recommend them. I plan to try some 1/4 or 3/8 Norton stones if I can find a supplier. But then I'll have to make a custom arbour so I'm in no particular hurry.

I originally started on this journey so I could true up the Jaws on my chuck. I just assumed that factory jaws had to be good for crap. So I made my jaw tensioner system and tool post grinder first. That whole project blew up in my face when I did the before grinding measurements and discovered what I had already was amazing. I was dumbfounded. Then I couldn't make up my mind if I was disappointed or thrilled!

I did do a bunch of other things with it just so I could say the time was not wasted. It doesn't have much clout so you can't get a job done quick, but if you are patient it does work.