Dremel on amazon: amzn.to/2GAUPEc Here i tear down a Dremel 8220 Cordless rotory tool, check out some of the internals, view the control method on scope, and give overall review.
My fairly new Milwaukee just burnt out cutting some aluminum downspouts. Thanks for showing us the inside of the 8220. The contacts are probably nickel plated brass and not stainless. Tomorow I will go buy an 8220 since I use a rotary tool all the time but don't want to to go back to a corded tool. Thanks for posting this informative video.
Thanks for the teardown video, it's very informative. The comparative Bosch model is GRO. The video further confirms my early observation that Dremel 8220 is a better design and make. The drive shaft between the motor hear and ball bearing is shorter. the back of the shaft housing is supported as well. these measures all make the Dremel vibrates less than the Bosch. Plus the shaft lock disabling function and other features, it is a definitely a better model than Bosch. By the way I have noticed you seem to have missed a U pin at the back of the housing to clip the two half pieces together. I can see the pin slot is there.
@Build It Better Very good teardown of Dremel 8220. Thank you very much. motor cutting out: I watched very closely and it looks like maybe the battery terminal was touching the mosfet heat sink? At 12:55, it looks like one of the contacts on the battery is barely touching the mosfet heat sink. At 13:09, you reinsert the battery which also moves it a few millimeters away from the heatsink. Then at 13:47, you wiggle the mosfet board and touch that battery pin again. The batteries are protected so it probably triped the li-ion protect circuit. I would guess that nothing was damaged. The protect circuit worked perfectly. shaft lock: Looks like a nice shaft lock. Was expecting just a hole in the shaft. The notched disk is quite nice. The shaft lock disable when tool is on is also nice. I have bumped that before on older dremels while running. I didn't break it but I did get the scary grinding noise. speed slider: Are there detents on the speed slider? It looks like a smooth slider, but at 18:59 it almost sounds like there are very fine detents in the plastic housing? Detents would be great. I had an older dremel with a totally smooth sliding speed control and it got loose after a while. When using the dremel, the speed would slowly increase by itself just from vibrations. Keeps you on your toes :) brushed motor: Looks like there is no way to change the brushes, but that isn't really a big deal. I have never changed the brushes before on older dremels, they last a really long time. Also, I found a whole replacement motor for $15, so even if the brushes die, the tool can be repaired. "www.ereplacementparts.com/motor-p-2268145.html?osCsid=dvbcuro7gtsecus1u0les7dp61"
Thank you for the kind words. You are absolutely correct, I was not paying attention and shorter the fets several times. I have used the dremel about 10 hours since the tear down and not have had a single issue with cutting out or speed control, so it seems to be a very robust protection circuit. I revisited some of the extra footage and discovered that the battery has a balance charge circuit and a protection circuit inside the battery, and there is also auto-reset fuses on the control pcb, so where if something shorts, it drops the battery voltage till the short clears then resets and allows power to flow again. I was expecting to see just a couple holes in the shaft for the shaft lock as well, and was pleased to see the notched wheel. Plus the housing around the shaft lock is isolated from the main body of the case, so if for some reason the shaft lock disable broke and the button was pressed and one of the notches broke off it would keep it away from the electronics and motor. I too have bumped the shaft lock on a few other rotary tools as well as grinders, and it will scare the crap out of you, especially when you are using fiber cutoff wheels and know what happenes when they explode. There are no appreciable detentes in the speed control but when you move the slider you can feel a slight detend every 5 notches which seems to be just enough pressure to keep the speed control slide where you set it. This one had a non serviceable motor , I know this is the newest version of the 8220, I no longer have my old one but it must have been an older revision as my old one had covers you remove in the case to replace the brushes. But ya, when the motor fails chunk it and replace the motor and the front bearing as well.
It appear to be one of the better Johnson motors that has a larger front bushing and possibly a ball bearing in the rear. Our company has worked with Johnson for years and they know motors really well.
Thank you for the kind words. I try and do right by people looking for honest reviews and not paid ones like most of the them on youtube to help people make an informed decision on what they want to buy.
Thank you. I do feel fortunate I can have the tools I have. Most are tools of the trade when you get into a technical job, not they are nice to have none the less. Thank you for subscribing. Have a great day.
Great video but I'm wondering about something. I have an 8220 that thanks to your video, I just replaced the rotor in, but one thing I didn't notice on yours that I had on mine is after removing the screws (5) which were T8 for someone who asked and after taking off that U shaped sort of bracket that surrounds the speed control, I still couldn't get mine apart. I found at the base which only has one screw, on the opposite side there was a U shaped bracket that you have to slide out to get the thing apart. This bracket is about 1/2" by 7/16. You can't see it with the battery in place and once you take the battery out, you only see a small part of it. I didn't see it in your video. Maybe it was left out when it was reconditioned?
Thank you for the great teardown video. Did you happen to see if they included a diode bridge on the input so it can handle batteries with opposite polarity? I realize it should be unnecessary given the mechanical battery keyonf, but the reason I ask is I've seen videos of where people have modified Milwaukee batteries to fit this Dreme. This is something I'd like to do as well since my Dremel charger broke but Dremel and Milwaukee batteries have opposite polarities when in the same orientation so I'm hoping to confirm I won't blow anything up when I plug it in before I plug in a Milwaukee battery.
I like the 8220 and I have 2 of them. One quit running and started smoking just before it quit. I think I burned up the motor but I replaced it and it still won't run. After replacing the motor what is the second thing I should try?
Excellent video, my Dremel 8220 when turned on flashes the Leds alternately as it appears on the video and does not work, I believe it burned the speed control board because the battery is ok.
With a multimeter at the motor terminal, when the micro switch is turned on, the 12 volts arrives and the motor tries to leave but it immediately cuts the voltage.
Yes, at some point the tool would experience harmonics which is perceived as vibration, each tool will hit it at a different speed but any rotating tool will experience vibration at a certain RPM then go away. I always run my tools at a speed that does not produce vibration, in my mind it makes them last longer.
How has the charger and battery held up so far? do you still get the same running time as you did when you first bought it or it's dropped dramatically? With this teardown, could you tell me at what timestamp did you show the brush in this 8220? I'll be changing mine, I need to know.
I still have it, same tool, same battery and charger. No issues with it at all. I still get about 1.5 hours of run time if I go easy on it. I don't believe I showed the brushes it the video, it still has the factory brushes in it.
@@builditbetter5610 Gotta be kidding me, this video was made in 2017(5yrs ago) now, how often do you use the tool and how long do you use it? once a day, week, month or just once a year? And where exactly is the brush if I were to change it myself?
@@Sir-Kay I use it a few times a week for detail work, projects and gun smithing, between 10 min and 2 hours at a time. I also take care of my tools, use as light of pressure as possible and don't dig into the material if I can avoid it, so that may be a contributing factor, I also clean it off and use compressed air to blow out all the crap in and around the air vents to keep the armature clean after each use. I'm as surprised as you that I'm still using using original battery, usually the battery is the first to go like in my Dremel Stylus, that battery it in died after 6 months.
Good review! One thing that would be (in my opinion) very interesting: Power comsumption (max speed and grinding). Dremel doesnt give information about the Watts of the cordless versioins.. so it´s not really possible to compare the power with cordless to cordet dremel.
What kind of MOSFETS are those? My motor stopped working and blew up those 2. I got a motor from a friend but I can't read the numbers on the MOSFETS and don't want to buy the whole assembly because my machine is not worth it. Also, does anyone know if I can use a compatible MOSFET just in case if I can't find the original ones? Thank you.
@@Elvices. Yeah. I kinda figured that out but again I couldn't find the numbers and/or the MOSFETs that's why I asked the question but nobody wanted to share with us their knowledge.
Love how they sand the chip nomenclature off so you can't replace it. Typical Bosch. My Dremel broke after a couple of hours. If I had known it was a Bosch product I wouldn't have bought it. Bosch used to be a great company and made dependable stuff but then the bean counters took control and it was all downhill since then. Yellow paint. WTF. Did they sand the numbers off of the FETs too?
>straight to high speed likely the mosfets have been shorted - power mosfets most common failure mode is dead short. Check drain-source with an ohm meter.
Dremel is made in several countries so I am unsure where this particular tools is manufactured. The label on the tool I own says its made in Mt.Prospect Illinois, USA. Tools you purchase may be manufactured somewhere else in the world. Dremel is a subsidiary of Bosch which has manufacturing plants in China.
Nice tech analysis of the guts of the tool. Thanks for your 'in'sight.
Thank you.
Very good video. You're straightforward and keep things simple. I appreciate that. Thank you and keep up the good work!
Thank you Tom.
My fairly new Milwaukee just burnt out cutting some aluminum downspouts. Thanks for showing us the inside of the 8220. The contacts are probably nickel plated brass and not stainless. Tomorow I will go buy an 8220 since I use a rotary tool all the time but don't want to to go back to a corded tool. Thanks for posting this informative video.
Excellent Work!!! Really helps in my buying decision.
Thank you for the kind words, best of luck with your new toy.
Thanks for the teardown video, it's very informative.
The comparative Bosch model is GRO. The video further confirms my early observation that Dremel 8220 is a better design and make.
The drive shaft between the motor hear and ball bearing is shorter. the back of the shaft housing is supported as well. these measures all make the Dremel vibrates less than the Bosch. Plus the shaft lock disabling function and other features, it is a definitely a better model than Bosch.
By the way I have noticed you seem to have missed a U pin at the back of the housing to clip the two half pieces together. I can see the pin slot is there.
@Build It Better
Very good teardown of Dremel 8220. Thank you very much.
motor cutting out:
I watched very closely and it looks like maybe the battery terminal was touching the mosfet heat sink? At 12:55, it looks like one of the contacts on the battery is barely touching the mosfet heat sink. At 13:09, you reinsert the battery which also moves it a few millimeters away from the heatsink. Then at 13:47, you wiggle the mosfet board and touch that battery pin again. The batteries are protected so it probably triped the li-ion protect circuit. I would guess that nothing was damaged. The protect circuit worked perfectly.
shaft lock:
Looks like a nice shaft lock. Was expecting just a hole in the shaft. The notched disk is quite nice. The shaft lock disable when tool is on is also nice. I have bumped that before on older dremels while running. I didn't break it but I did get the scary grinding noise.
speed slider:
Are there detents on the speed slider? It looks like a smooth slider, but at 18:59 it almost sounds like there are very fine detents in the plastic housing? Detents would be great. I had an older dremel with a totally smooth sliding speed control and it got loose after a while. When using the dremel, the speed would slowly increase by itself just from vibrations. Keeps you on your toes :)
brushed motor:
Looks like there is no way to change the brushes, but that isn't really a big deal. I have never changed the brushes before on older dremels, they last a really long time. Also, I found a whole replacement motor for $15, so even if the brushes die, the tool can be repaired. "www.ereplacementparts.com/motor-p-2268145.html?osCsid=dvbcuro7gtsecus1u0les7dp61"
Thank you for the kind words.
You are absolutely correct, I was not paying attention and shorter the fets several times. I have used the dremel about 10 hours since the tear down and not have had a single issue with cutting out or speed control, so it seems to be a very robust protection circuit. I revisited some of the extra footage and discovered that the battery has a balance charge circuit and a protection circuit inside the battery, and there is also auto-reset fuses on the control pcb, so where if something shorts, it drops the battery voltage till the short clears then resets and allows power to flow again.
I was expecting to see just a couple holes in the shaft for the shaft lock as well, and was pleased to see the notched wheel. Plus the housing around the shaft lock is isolated from the main body of the case, so if for some reason the shaft lock disable broke and the button was pressed and one of the notches broke off it would keep it away from the electronics and motor.
I too have bumped the shaft lock on a few other rotary tools as well as grinders, and it will scare the crap out of you, especially when you are using fiber cutoff wheels and know what happenes when they explode.
There are no appreciable detentes in the speed control but when you move the slider you can feel a slight detend every 5 notches which seems to be just enough pressure to keep the speed control slide where you set it.
This one had a non serviceable motor , I know this is the newest version of the 8220, I no longer have my old one but it must have been an older revision as my old one had covers you remove in the case to replace the brushes. But ya, when the motor fails chunk it and replace the motor and the front bearing as well.
It appear to be one of the better Johnson motors that has a larger front bushing and possibly a ball bearing in the rear. Our company has worked with Johnson for years and they know motors really well.
nice vid man. very well done. big ups
Great skills and knowledge man very impressive 👍👍👍
What a great review. Very professional. You deserve a lot of subscribers. I’m now one.
Thank you for the kind words. I try and do right by people looking for honest reviews and not paid ones like most of the them on youtube to help people make an informed decision on what they want to buy.
Very nice video !
a lot of nice test tools you have nice job
Thank you. I do feel fortunate I can have the tools I have. Most are tools of the trade when you get into a technical job, not they are nice to have none the less.
Thank you for subscribing.
Have a great day.
Great video but I'm wondering about something. I have an 8220 that thanks to your video, I just replaced the rotor in, but one thing I didn't notice on yours that I had on mine is after removing the screws (5) which were T8 for someone who asked and after taking off that U shaped sort of bracket that surrounds the speed control, I still couldn't get mine apart. I found at the base which only has one screw, on the opposite side there was a U shaped bracket that you have to slide out to get the thing apart. This bracket is about 1/2" by 7/16. You can't see it with the battery in place and once you take the battery out, you only see a small part of it. I didn't see it in your video. Maybe it was left out when it was reconditioned?
Great video, did you say it brushes are in the motor how do you change them, or don’t you have to change them thanks again outstanding video
I'm missing one information. What size of torx screwdriver is necessary to remove screws???
Thank you for the great teardown video.
Did you happen to see if they included a diode bridge on the input so it can handle batteries with opposite polarity? I realize it should be unnecessary given the mechanical battery keyonf, but the reason I ask is I've seen videos of where people have modified Milwaukee batteries to fit this Dreme. This is something I'd like to do as well since my Dremel charger broke but Dremel and Milwaukee batteries have opposite polarities when in the same orientation so I'm hoping to confirm I won't blow anything up when I plug it in before I plug in a Milwaukee battery.
Do you know how to go about fixing the speed control? Mine randomly stopped allowing speed adjustment.. now it just goes full speed
I like the 8220 and I have 2 of them. One quit running and started smoking just before it quit. I think I burned up the motor but I replaced it and it still won't run. After replacing the motor what is the second thing I should try?
Excellent video, my Dremel 8220 when turned on flashes the Leds alternately as it appears on the video and does not work, I believe it burned the speed control board because the battery is ok.
YURI DI LURRAWI
thank you,
Does the motor try and turn on at all or does it just flash the lights back and forth?
With a multimeter at the motor terminal, when the micro switch is turned on, the 12 volts arrives and the motor tries to leave but it immediately cuts the voltage.
YURI DI LURRAWI habe you tried to spin the motor by hand as you turn on the switch to see if the brsuhes are stuck?
Even turning by hand it does not start and plugging directly into the battery works perfectly.
I have a issue with over heating or over rpm causing the led to flash
What size torque bit to take a part?
what odd screwdriver do you need to disassemble?
Nice video!
Is it normal for it to have some vibration around 20.000 - 25.000 RPM ?
Yes, at some point the tool would experience harmonics which is perceived as vibration, each tool will hit it at a different speed but any rotating tool will experience vibration at a certain RPM then go away. I always run my tools at a speed that does not produce vibration, in my mind it makes them last longer.
How has the charger and battery held up so far? do you still get the same running time as you did when you first bought it or it's dropped dramatically?
With this teardown, could you tell me at what timestamp did you show the brush in this 8220? I'll be changing mine, I need to know.
I still have it, same tool, same battery and charger. No issues with it at all. I still get about 1.5 hours of run time if I go easy on it.
I don't believe I showed the brushes it the video, it still has the factory brushes in it.
@@builditbetter5610 Gotta be kidding me, this video was made in 2017(5yrs ago) now, how often do you use the tool and how long do you use it? once a day, week, month or just once a year?
And where exactly is the brush if I were to change it myself?
@@Sir-Kay I use it a few times a week for detail work, projects and gun smithing, between 10 min and 2 hours at a time.
I also take care of my tools, use as light of pressure as possible and don't dig into the material if I can avoid it, so that may be a contributing factor, I also clean it off and use compressed air to blow out all the crap in and around the air vents to keep the armature clean after each use.
I'm as surprised as you that I'm still using using original battery, usually the battery is the first to go like in my Dremel Stylus, that battery it in died after 6 months.
Good review!
One thing that would be (in my opinion) very interesting: Power comsumption (max speed and grinding).
Dremel doesnt give information about the Watts of the cordless versioins.. so it´s not really possible to compare the power with cordless to cordet dremel.
Excellent idea, I will work on making a follow up visit to explore the power consumption on the cordless version. Thank you so much for your input.
Cool! I am looking forward to the video :)
What kind of MOSFETS are those? My motor stopped working and blew up those 2. I got a motor from a friend but I can't read the numbers on the MOSFETS and don't want to buy the whole assembly because my machine is not worth it.
Also, does anyone know if I can use a compatible MOSFET just in case if I can't find the original ones?
Thank you.
Same and not one but two. 🙄 I found one but not the other one, which is different.
@@Elvices. Yeah. I kinda figured that out but again I couldn't find the numbers and/or the MOSFETs that's why I asked the question but nobody wanted to share with us their knowledge.
Love how they sand the chip nomenclature off so you can't replace it. Typical Bosch. My Dremel broke after a couple of hours. If I had known it was a Bosch product I wouldn't have bought it. Bosch used to be a great company and made dependable stuff but then the bean counters took control and it was all downhill since then. Yellow paint. WTF. Did they sand the numbers off of the FETs too?
Can someone tell what is the motor part or model number??
2610005460
Well I opened my up to see what was wrong with mine and it looks just like this one. Mine goes straight to high speed :(
same problem with me, i wish i knew what to replace and where to find it......
@@LuminousSpace can’t u return it from where u got it and get them to put it under faulty and get a new one
>straight to high speed
likely the mosfets have been shorted - power mosfets most common failure mode is dead short. Check drain-source with an ohm meter.
Is it true the battery only lasts for 10-15 minutes?
If the dremel rotary tool was made in the USA
Dremel is made in several countries so I am unsure where this particular tools is manufactured. The label on the tool I own says its made in Mt.Prospect Illinois, USA. Tools you purchase may be manufactured somewhere else in the world. Dremel is a subsidiary of Bosch which has manufacturing plants in China.
Every hobbyist and homeowner should check the waveform before buying a power tool! that's just common sense.
These are far too expensive for the quality of the components used.
100% agree. In this instance you are paying for a name but not receiving the quality we would come to expect considering the price point.