Dremel while runnibg cuts out if i wiggle the case or touch the brush cover it starts back up.

Look at the clogged teeth on the blade. Copper does that.
Use a pair of tin snips.

Problem sounds like the switch. Easy to replace and a lot cheaper than a new Dremel. One other thing comes to mind. Blow out the Dremel with compressed air. I could be to dusty and overheating.

sounds if your tool has a loose or broken brush this is a small carbon object inside that makes motor run, dremel does sell replacement brushes for most of what they mfg. look where ever real dremel bits and tools are sold ck package back to see if your model number is serviced by this brush pack

There should be a second brush. Look along the motor - you're looking for a spot where the armature (the part that rotates) is surrounded by a ring of little straight copper-colored bars. That's the "commutator" section. The brushes run against the copper bars.

Look on the outside of the plastic shell - there may be two large plastic screws, one on the outside of each shell half, right about where the commutator would be on the inside. Those are your brush holder screws; you should be able to change the brushes from OUTSIDE the tool without opening it. Some tools are built without external brush holders like that, but most have external brush holders.

If you find external brush holder screws, then track down the second brush and set it aside. It MAY be hanging from the brush holder in one of the shell halves. Unscrew both brush holders and remove them from the shell. Set them aside and reassemble the motor back into the shell. If the brushes are really short, like if they're nearly cube-shaped, then it's time to replace them. If not, try them again.

Insert one brush into each of the holes the brush holder screws came out of, and put the brush holder screws back in. Be careful not to cross-thread them. Try the tool.

If it still won't run, it's possible that an armature winding has given up the ghost and it's time to replace the tool...

try installing a new set of brushes in it i have fixed mine lots of times by doing just this !!! new brushes are sold where ever real dremel tools and bits are sold ck package back for your model number

No.. the issue issue is the switch inside. when your Dremel 4200 stop working, press firmly the grey area between the speed selector and the brush housing. I think this a defect in the design of the 4200.

Check and replace brushes as necessary. Also, check that the actual electrical switch is functional. I had to add a drop of crazy glue on the tip of the interior plastic handle housing that supports/puts pressure on the electrical switch to keep it in position. The off/on thumb slider actually extends well into the housing and activates the electric switch by moving back and forth. Over time, the plastic wears and does not plunge the on off switch button. A drop of glue on the tip of the plastic post extends it & causes enough pressure to make the electric switch to function again. Brushes (filed to fit) and glue = good as new Dremel :o)

Most of our issues with Dremel tools is with the plastic brush holder. If the tool is used for exetnded periods of time or 'leaned' on too much the holder will get hot enough melt and keep the brushes from contacting the armature properly. Try taking your brushes out, if they don't slide in and out of the holder freely you may need to file or cut away any plastic that is holding the brushes off the armature. This may require you taking the brush holder out so you don't damage the armature. Be careful with the brush holder, it is not available as a replacement part.

You described intermitten pwer supply, follow this procedure:

1. check your power cord for breaks or kinks, especially where it join the piece or plug
2. if cord is ok, check/replace brushes.

To check/replace brushes on dremel 395 follow this procedure:

1. switch off unit, remove power cord.
2. with flat screwdriver remove gently brush covers, WATCH FOR LITTLE SPRINGS!!!
3. check brushes for wear, springs if connect correctly, if brushes are thinner than 3.2mm (1/8") replace with new ones, this check should be carried regardless after about 50hrs of use, brushes last about 50 to 60hrs in normal use.

In unlikely case that it is switch, this is as well very easy replaceable.

1. switch off unit
2. remove cable from power source
3. remove brushes following previous procedure
4. remove collar from front of the piece
5. remove side screws and gently pry apart halves, label side up
6. replace switch
7. screw pieces back in reverse order
8. replace back brushes.

All parts are easy available, when purchase brushes or switch, be aware that they fit only particular model!

I would recommend clean table with butcher paper on top, torx/hex screwdriver, philips screwdriver, flat screwdriver - these vary from country to country, I cannot provide what exactly tools you will need, you need to check what screws are holding your piece together, little long nose pliers can be helpful as well.

As you pull handpiece apart put your parts in order in whihc you pulled them apart, when you put them back, it will be easy to put them back in reverse order in which them come apart. For changing brushes you need about 5min (assign 15min), for changing switch or faulty power cord you need about 1h (assign 3hrs), assigned time is theoretical, prctically multiply it by 3...

If you have anymore questions, or require more detailed instructions, do not hesitate to follow this thread and leave note.

Leave note how it go, thanx!

Dremel may not be the way to go. ABS and poly plastic likes to melt and ball up on a Dremel