Dremel Repair

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Introduction: Dremel Repair

About: Professional work in various electrical and mechanical fields, obscure sense of humour and typically willing to help... Currently under contract designing environmental monitoring equipment.

So my Dremel 395 died mid project!

No power no strange noises! it was just mocking me and acting like it was unplugged!

I figured that since it didn't smell of burning metal I should be able to get it going again.

Step 1: Assess the Mess!

I did notice that it was running hot for the past little while.

First unplug the tool.

Check to see if the shaft spins freely, if not you may have a bearing problem. You can sometimes free up a bad bearing with light oil but noisy bearings mean mechanical damage and it should be replaced as soon as possible. If the bearings are bad then the whole armature will need to be replaced. this is available online for around $17.

If it does then next check the brushes. These are under small blue screw caps on my tool. They should remove easily and have lots of carbon "brick" left.

On my tool one came out easily while the other separated from the spring and remained in the brush holder.

So it looks like I have a stuck brush which has worn down and no longer makes contact with the commutator (more later)! This explains the no power situation!

Step 2: Disassembly

Remove the hanging clip

Remove the body screws, mine were torx 15

Gently separate the body halves making sure that no small parts fall out, like the shaft lock assembly at the nose of the tool.

Remove the motor assembly from the body making sure to note which side is up with respect to your dis-assembly order.

Remove the rubber spacer at the rear of the motor shaft

Gently pull the brush block assembly rearward to remove it.

Step 3: Repairs

Use a rounded tool like a screwdriver shaft and gently push the stuck brush out of the brush block.

Check for damage, in this case there was none and I was able to re-use the brushes and brush block. Gently dress any warped or melted plastic with a needle file or sand paper.

Reattach the spring to the brush using mild force.

Test for proper fit by inserting the brush to make sure that it doesn't bind.

I suspect that the heat was caused by a dirty and worn commutator ( where the brushes contact the rotor), which in turn caused the brush to melt into the carrier.

Using a very fine sand paper ( 800 grit) clean and dress the commutator until it is shiny and smooth. Clean the black lines between the segments of the commutator using a brass brush to remove any chance of shorting.

Step 4: Reassembly Notes

The brushes go in last! Severely worn brushes should be replaced!

The brush holder connects to the motor assembly via friction fit contacts. Gently press them into place.

Reattach the rubber spacer to the rear bearing and place the motor into the housing.

Place the other half of the housing in place and test that to motor freely spins, if it grinds, open the case and flip the magnet assembly of the motor over and re-install, it should be smooth now.

Screw the case shut.

Look for a dark line on one edge of the brushes, if there is one, then this installs in the direction of the arrow. Dark line in the direction of travel. Install the brush caps.

Plug in the tool and test. If it doesn't spin at this point then you most likely have a burned out switch, unfortunately that will need to be replaced. The switch is available online for around $16.

Mine now works better than it has in a very long time!

Now back to the original project...

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    41 Discussions

    0
    LGS2013
    LGS2013

    2 months ago on Step 4

    Decent instructable, actually, more than decent...it's a bunch better than most. I have just one exception...you are assuming the reader knows and can identify each part by the name you use. Maybe consider numbering your images to a coordinating written line of instruction? Or, maybe add a photo or diagram of all parts? Or possibly adding "intermediate level" to the title? On a more positive note, I really appreciate the number of images you provide along the way...makes a huge difference when following a written tutorial. If I just knew what they were of or what part of your Instructable they were depicting, this would be an awesome Instructable.
    On a different note, if you could please help me with a reassembly issue?
    There is a half-circle metal band that I had placed where it came from before attempting to reconnect the two halves, but it shifted during the reconnect and it got partially stuck in the casing and when I took it out so that I could reposition it, I bent it slightly. The tip was creased by my tweezers and I can't seem to get it back in the exact shape which I believe, is causing it to get stuck again. When I turned on the tool it sounds like a metal flap is being held against fan blades. Any suggestions, tips, instruction? I'd greatly appreciate it! It's enough of an issue that I am unable to click the two halves of the case together properly, it won't snap together, something is in the way. Please help.
    :-)
    T.I.A.

    0
    Builders Shed
    Builders Shed

    4 years ago

    Hey, i just bought the dremel 200 series two weeks ago at bunnings and when i set it on low mode it just spins really sloow. The manual says that on slow mode it spins 15.000 rpm but it doesn't seems to happen. it just spins like 30 rpm. Can anyone tell me what happened and how to fix it?

    0
    ChristopherG69
    ChristopherG69

    Reply 7 months ago

    Hi Builder Shed.
    Same here. Yestrday, I bought a 200 from bunnings. Slow mode does not seem like 15,000. Did you resolve this? Should I just take it back and upgrade to the 3000 series variable speed?

    0
    Bengtartist
    Bengtartist

    Reply 2 months ago

    You'll have more versatility with the variable speed models. But we take what we can afford at the time. I hope you figured out the issue. Sounds like the switch is needing some attention.

    0
    Bengtartist
    Bengtartist

    2 months ago

    I find that when I disassemble my Dremel model 395's (I have 3 of them) it is good practice to clean any dust buildup from past projects. All inside the plastic body and the variable switch body. Q-Tips and alcohol are an easy way to go here, and maybe some fine sandpaper like 400 to 600 grit in case any electrical connections need cleaned. The commutator as well, just don't be aggressive with the sanding. A good cleaning will help with the longevity of your tool, and familiarize you with the unit's construction. And when your variable speed switch eventually burns out (the two little contact slides get worn off!) and you can't add a smidge of solder and copper to get it going again, then an eBay order for a couple switches is in your future. Also knowing how to clean and troubleshoot these can score you cheap units from pawnshops and garage sales.



    0
    thegrimbarian
    thegrimbarian

    2 years ago on Step 4

    My Dremel 3000 just gave up like that today when I was trying it out for carving with a flexi shaft; I have only used it for cutting some laminated flooring before. I will try what you suggest. I did take one brush out and it came out freely; but as I didn't really know what I was doing I put it straight back in and didn't take the other one out. I will try that tomorrow. I tried taking the casing apart by taking the screws out. I thought the hanger was still holding it together but wasn't shore so I put the screws back in in case I made things worse.

    0
    Bengtartist
    Bengtartist

    Reply 2 months ago

    Take pictures or videos of each disassembly step so when you go to reassemble your Dremel you'll get it done without any issues. B4 long you'll be able to strip down an old model 395 and put it back together again within 10 minutes.

    0
    dsaav
    dsaav

    8 months ago

    This fix worked perfectly, thanks so much! I've had the same Dremel (300 series) for almost 15 years and never had an issue. Then today when I went to use it today it just wouldn't turn on. I followed your steps, in addition to using compressed air to blow out all the accumulated dust from inside the tool, and now it's working great!

    My favorite part "Now back to the original project..." - yeah no kidding! Fixing this was an annoying side track to the project I set out to do tonight.

    0
    melindacrowe61
    melindacrowe61

    Question 1 year ago on Step 2

    My dremel multitool was working fine. No noses or smell. It jumped and stopped. Now it will not turn back on.

    0
    Random_Canadian
    Random_Canadian

    Reply 1 year ago

    Several things to check. you will probably need a multimeter. If the tool spins freely, the cord, the switch or the brushes could all be at fault.

    0
    aceE5
    aceE5

    Question 2 years ago on Introduction

    My low doesn't work but my high does. What does this mean? Model 200

    0
    MattP167
    MattP167

    3 years ago

    My dremel died as I was cutting PVC at first it was shuddering and shut off the on real quick a few times and when it hit it started working again that lasted 5 minutes,then completely died hoping to get it fixed so I can continue with my project.

    0
    Theo kane
    Theo kane

    5 years ago

    Hi there, My dremel 3000 stopped working. I've switched, worked for a few seconds and stopped. Checked the fuse, the brushes, are fine. Opened and checked for current continuity, I have current going though, from the circuit board to the variable switch and also I get current from the two of the four probes going through to the element. What do you thing the problem might be? How do I check the element if it works and how do I troubleshoot any further problem areas. I hope I am making my self clear, though my knowledge of electrical and electronics is very basic.

    0
    amiir
    amiir

    Reply 4 years ago

    hey there, sorry for my bad english. your dremel is not dead. you can fix it so easy.

    1 extract brushes (Carbons)

    2 remove stickers from 2 side of the dremel (Dremel 3000 and the other side)

    3 remove all 4 screws with T15 screw driver

    4 disapart all parts (Motor, Speed Control Unit and little PCB that started with Main wires.

    5 look at the motor body from top. you will see a thin wire is free from its place.

    6 solder that wire too correct place and here you go. your dremel is fine.

    assemble it just like you dis assembled it. DONE.

    0
    Alpha_oi
    Alpha_oi

    Reply 4 years ago

    you are my hero thank you so much!

    0
    amiir
    amiir

    Reply 3 years ago

    You're welcome Alpha_ol

    I'm glad I could help

    it was my problem too in 3 month ago. i just bought a new dremel 3000 and a set of wood cutter bit. i turn on my dremel with 30000rpm but wood cutting bits made for 20000rpm and i feel a hard vibrate in my hand and after 3 sec my dremel just died! i was so sad because i love my dremel! after i take it apart i just saw the wire which get cut of from its place.

    i hope your dremel work for you at least 10 years :))

    0
    bobdole1221
    bobdole1221

    Reply 4 years ago

    I know its been two months. But sometimes when taking your dremel apart. You may mis-align the plastic piece in witch the motor itself seats into. You will (atleast on the 3000 model) see 4 small prongs make sure those are in the correct position. I dont know all the technical terms. But if your wires arent the problem the prongs not meeting the electrical source is probably the culprit. Mine was also touchy when i came to the graphite brushes

    0
    Calgary84
    Calgary84

    4 years ago

    do you have any "tricks" regarding the wiring? I took mine apart to clean, but for the life of me cannot get it to turn back on. I believe the culprit to be the connecting wires (white and black), but despite numerous configurations I cannot get the damn thing to turn on. advice maybe?

    0
    bobdole1221
    bobdole1221

    Reply 4 years ago

    I know its been two months. But sometimes when taking your dremel apart. You may mis-align the plastic piece in witch the motor itself seats into. You will (atleast on the 3000 model) see 4 small prongs make sure those are in the correct position. I dont know all the technical terms. But if your wires arent the problem the prongs not meeting the electrical source is probably the culprit. Mine was also touchy when i came to the graphite brushes

    0
    Random_Canadian
    Random_Canadian

    Reply 4 years ago

    You will need to use a multimeter to check this. with the tool unplugged, use resistance to continuity to test if you have a direct path between the plug end and the brass pad that the brush sits in. You should have a path on each side one white and one black. If not check the switch is in the fully on position. if moving the switch does not work then most likely the switch or cord is bad.

    I hope that this helps and sorry for the late reply.