Magnets or motor brushes?
Square carbon dust shedding blocks with slight curves on the ends. Blue wires coming out of them. Held against the spinning shaft with a cheap coiled spring. Held in place and semi square by a square tunnel made out of very very brittle plastic.
I know I messed up, and it is assumed that anyone opening this would know what they are doing, but would have been nice if this piece were a little more durable.
I’ve almost got it fixed. Round two of the epoxy dabbing is curing now.
Interesting name for solid blocks. I would have called them motor rubs or rubbers, but I guess on bigger motors they must have flexible fingers to maintain contact.
Went ahead and ordered the replacement part for $12 plus shipping. But now there is a thread on this for the next guy… A smart man learns from his own mistakes, but a truly wise man learns from the mistakes of others … sometimes by searching a forum
They don’t have “bristles” except sometimes on very tiny, low power motors, as it happens. The larger the electric motor, the bigger and more solid those things get. They are wear parts though, and are designed to be allowed to wear down over time, and eventually be replaced as a part of maintenance.
Yup. That’s why they have springs. As they wear down, the springs keep constant pressure.
Cool. Figured that out when searching for parts.
Which by the way, like anything else, the parts if bought separately would cost 10X the cost of a completely new one.
The calculus is such that It would be better to buy a new one for donor parts, If I had bought just the brush holder and a spare set of ‘brushes’ or anything else.
I suppose that if you went through brushes a lot and bought them in bulk it would work out better financially.
In all my time woodworking, I’ve only ever known a handful of people that have used a hand router enough to require brushes to be changed. And most of those people are on this forum running their 660 multiple hours a day.
I have a few tools that I’ve replaced brushes in. Plus car parts, lol. Starter brushes are also a wear item.
If you’re not in a hurry to buy them, they can be cheap. If I have to replace them once in a tool, I usually buy multiple sets. Often ones from the same manufacturer can be used in a different tool, too. Sometimes ones from completely different manufacturers can, too. Also, they’re made to wear down, so oversized ones can be filed to fit. I’m 99% sure that the brushes in my ~35 year old skillsaw are actually filed down starter brushes originally bought for a 1977 Chevy. They’re made from material much softer than the copper contacts that they brush against, so they’re very easy to shape.
Anyway, you ought to be able to get those for much less than the cost of a parts router.
You may also want to know that these parts are why they are called a “brushed” motor. Compared to a “brushless” motor.
A brushed motor has the coils on the spinning part and the magnets on the outside. The current needs to flip from one direction to the other as it spins, so the magnets change polarity and it will spin. The brushed just touch different pads, so it is easy for it to change directions (it is simple).
A brushless motor has the magnets on the spinning shaft and the coils on the outside. The current needs to change direction in the coils, but there isn’t a mechanical solution for that, so you need a smarter driver.
Steppers are brushless motors with two coils.
Thx Jeff I see what you are saying, but not sure it explains the terminology of “brushes” or “brushed”.
Unless I guess, the blocks aka brushes, “brush” against the different copper pads. That may have just made the logical lightbulb flicker. So “brush” in the original application of this to a motor is verb not a noun… still having cognitive dissonance calling these block things brushes tho.
I wouldn’t be surprised if the original parts were brushes and the name followed the function, even though they were replaced with chunks of carbon.
You’ll start seeing these everywhere. Here are the holes to access them on my kitchen mixer:
Rad mixer. Same shade as Prince’s motorcycle.
Sneak Preview of the case. I feel like this should have a purple saber light coming out of the collett.
Pro-tip: don’t order replacement parts from M&M tools. They screw you with the 3 week wait. If I wanted to order from China, I would have ordered FROM china. Found the brush holder on ebay. See I finally got comfortable calling it a brush.
So worth it for the look, don’t you think?
Looks really good. Can’t wait to see it in the machine.
My 3yo has a tiny light saber key chain. She thinks it is a “light saver”. She runs around the house pointing it at people and screams, “I saved you!”.
What a fun age. Have a 13 y/o here, but the things they say are the best. I still call our washing machine the “wash-a-my-clean” because it is so poetically fitting.
Yep, I had rough figured a month long build but have some many other projects going and doing the enclosure was new territory and skills for me.
Here is what I did last night
Wha?! How did you do that? You should make a new thread with that and share some of the process. Looks amazing.
I didn’t use a CNC, but I guess you could make it with a tiny bit and black infill. ok will share in the right category
@Zymurgist I agree with Jeff I’d love to see more in your project.