Dremel tool problem

I have a problem with my corded dremel tool operating intermittently,
or only operating when I apply pressure to the brush caps. I haven't
tried replacing the brishes, because they seem fine, longer than the
1/4" that dremel recommends replacing them at. I've cleaned them off,
which doesn't seem to help much, or for very long.
I suppose this is a fairly common problem, because the dremel website
has this to say:
Q: The MultiPro stops unless I keep pressure on the brush caps. Why?
A: That shouldn't happen. Send the tool in to our service center.
Oh, so that shouldn't happen? Thanks dremel. Anyone know about fixes
for this?
Thanks,
Adam
Reply to
clumsymechanic
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Sounds like a loose/intermittent connection to the brushes themselves - check the wires going to the brush holder on each side........
Andrew VK3BFA.
Reply to
Andrew VK3BFA
Sounds like the commutator bars have built up dirt/corrosion. I use household copper cleaner on a cotton swab to clean them. Then burnish with a scrap piece of canvas or leather. Bugs
Reply to
Bugs
Stick the plug in your pocket when you do it. I do this myself just to be certain its definitely not plugged in..
rob
Reply to
Rob
I use an erasor to clean the bars and it works pretty well for me.
In addition to the plug in the pocket technique I have a tendancy to short a screwdriver across power terminals when working on electric gear that is de-energized because if there is a mistake I'd rather fry a screwdriver than a piece of me.
Reply to
bamboo
I had a new "Dremel-type" tool which would only work if you squeezed the plastic bush caps. The bushes, wires & spring seemed OK - then I noticed the plastic caps had burrs inside them. I trimmed them off with a craft knife, re-assembled and everything was fine.
Reply to
PR
A-hah!
I tried applying pressure to only one brush cap at a time, and it did in fact seem as though only one side of the tool was sensitive this way. I think the problem was corrosion of the contact which meets the spring that pushes the brush down. So that problem's solved.
I seem to have another problem now though, a tremendous noise at the highest speed setting. I looked in at the commutator bars as some posters suggested, from what I see they resemble the image 'streaking' on this page:
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I suppose it couldn't hurt to try and clean them, and possibly replace the brushes anyway, which on second look are closer to 1/4" than I thought. I'm unsure how exactly to clean the commutator bars.
I don't have the right size torx bit to disassemble the tool, and while I could go get one (no user serviceable parts inside? I'll be the judge of that) I'm wondering if it wouldn't be easier to just poke a q-tip damped with alcohol down the brush slots.
How effectively could I clean it this way? How necessary is a proper cleaning compound? How likely is this the cause of the noise? How likely is it that proper disassembly would reveal the cause of the noise?
Lots of questions,
Thanks guys.
Reply to
clumsymechanic
You can safely disregard a portion of my last post - the tremendous noise was from running the tool with a heavy grinding bit with a wobbly shank. A foolish mistake, and a bit that I have now discarded.
I'm still wondering if I can give the commutators a quick clean with a qtip though.
Adam
Reply to
clumsymechanic
Spend $150 on ebay and get a Foredom. Dremel's are a throwaway tool.
Steve
Reply to
Steve B
Hi Steve,
The dremel is only a throwaway tool if I throw it away.
As it is I've restored it to full functionality at no cost. The man at the hardware store confirmed my initial feeling that the brushes don't need replacement, and suggested I try pulling the springs out a little to increase brush pressure. Aside from that I'll try to give it a bit of a clean, the man at the hardware store also offered to disassemble it for me if I brought it in. Very helpful shop.
Thanks for the opinion on the Foredom brand. When I bought the dremel six years ago it seemed to me at the time to be the best available, and I've been quite happy with it. I can't remember what I payed for it, which is always a good indication that a tool has payed for itself, IMO.
Adam
Reply to
clumsymechanic
When I was a kid, I unscrewed the brush cap on a plugged in old kitchen mixer motor and grabbed that spring, barefoot on the dirt barn floor. That was entertaining and educational. My arm was sore for a while, and I've been a lot more careful around ac since.
Pete Keillor
Reply to
Pete Keillor
Your kind words have activated my guilt button ......
Perhaps I was a bit too harsh. What I MEANT to say was that if you need the tool for a lot of hard continuous work, the Dremel won't last as long as a Foredom.
I went to my audiologist the other day. (for you young farts, that is a hearing aid person for old farts) He was having a problem with his Dremel. Said he had worn out three of them. I suggested he look at Foredom, and he was unaware what I was talking about.
I know a TON of work has been done with Dremels. Some of that work was actually necessary. ;-) Lots of artwork, polishing, cleaning, repairing items where there was no other way. Solving problems when there seemed to be no solution.
It's the worker, not the tools. Timeless artwork has been created with hammers and chisels and horsehair brushes with homemade paint.
I did not mean to dis Dremel.
Steve
Reply to
Steve B
I've had several Dremel tools die that way.
Finally got a proper air driven die grinder!
Reply to
Richard Lamb

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