Review on Dremel 90930 05 Carbon Brush Motor by Viswanath Lopez

I bought this unit based on the only review that it worked with the Dremel 4000. I base my rating on that. So will this work with my Dremel 4000? Yes, but it is definitely NOT designed for the Dremel 4000. The copper nib is longer and thinner than the original. So when you insert it it may be pushed in at an angle, it won't make good contact, so DO NOT use this spring! To use OEM nibs you will need to shave the brush attachment point a bit with sand. paper or folder. It's quick and easy enough. The 90930 brush is smaller, so it's likely to wear out faster and at a slight angle over time. In summary, it is definitely not intended for use on a 4000. But it CAN be custom made. You have easy access to the right replacement parts, get them. If you don't, as I live abroad, this is a viable alternative. I hope this helps in solving 4000s installation issues.