Review By Dean Bielanowski  Dremel Website -

Dremel 4000 Rotary Tool

By Dean Bielanowski

Dremel rotary tools have been around for many years, and have been the preferred choice of tool for certain hobbyists and homeowners because they offer a wide range of applications for smaller scale work. I have owned several rotary tools similar to the Dremel in the past and have a rotary tool that gets occasional use in my workshop today, and there is no doubt they come in handy for certain tasks. I managed to get my hands on a new Dremel 4000 to review on this site, and it will be interesting to see how well this new Dremel model performs with various tasks around the workshop, around my hobby bench, and around the home.

The Dremel 4000
The Dremel 4000 is a powered rotary tool. Think of it as a mini-handheld router, because essentially that is what it is, but it can do a lot more than a router can because of its size and features, but naturally, it cannot perform certain large scale functions as quickly as a full-sized router can. The 4000 model is a corded version in the Dremel lineup and runs off 120v 50-60Hz mains power supply with a 1.6Amp current rating.

The beauty of a Dremel type tool is that there are MANY accessories available that allow you to perform many different types of tasks. You can get circular saw blades, grinding discs, polishing discs, drill bits, small router bits, wire brushes, sanding drums, carbide burrs, plastic cutting cones, you name it... The versatility of these tools for small scale jobs is quite amazing really. It is the type of tool you think about when you find yourself in a situation where conventional larger power tools just don't seem to be the right tool, or simply cannot be the right tool for the task at hand.

The Dremel 4000 is a multi-speed rotary tool, and allows operation in a range from 5,000 RPM all the way up to 35,000 RPM. This speed is variable and controlled via a dial at the back end of the housing and is thoughtfully marked with numbers between those ranges. My el-cheapo rotary tool I have in my workshop simply has letters marked A, B, C, D and E so it is difficult to tell just how fast the collet is spinning with those alphabetical markings. It is much more logical to use a numerical system that matches the router speeds for any particular setting, allowing you to accurately dial in a speed that suits the type of bit, cutter or grinding attachment in use on the Dremel. The wide speed range also makes it useable on different materials. Certain materials like plastics are prone to overheating and melting through excessive friction when high RPM cutters are engaged, so lower RPMs are required to help avoid melting through prone materials. On the flip side, grinding wheels and small diameter router bits, for example, can work better at higher RPMs so you will implement the higher end of the speed range for those type of tasks. The 4000 model features a soft-start to remove any sudden power-up jolting of the tool. This makes it easier to handle and use for various tasks and is an added safety feature.

The collet, which is the piece that tightens around and secures the shank of the various accessory bits you use in the Dremel, is available in various sizes, being 1/32", 1/16", 3/32" and 1/8". The majority of bits available for the Dremel and similar rotary tools have a 1/8" shank, so a 1/8" collet is supplied in the Dremel 4000 kit to suit. If you require a collet of another size mentioned here, you can buy those separately as required. The Dremel 4000 kit is available in various forms, depending on how many accessories you wish to purchase or have included in the box. The kit we are reviewing is the US$79.99 retail box which includes 2 major accessories and 30 assorted bits. Other available kits include 3 major accessories and 34 assorted bits for US$89.99 retail and another with 6 major accessories and 50 assorted bits for US$149.99. Of course, these extra accessories and bits are all available separately too should you wish to purchase later, although it will likely cost more buying these individually later than buying them as a kit to begin with, so determine as best as possible which Dremel 4000 kit will suit your current and future needs and start with that if you want to invest a little more now to save a greater amount later.

To give you an idea of the inclusions in the 2/30 kit (as reviewed) this is what comes in the box:

Major Accessories: Adjustable circle cutting and straight edge guide; sanding guide
Minor Accessories/Bits: Rubber sanding drum with 6 assorted grit sanding pieces; polishing mandrel with 2 polishing wheels; 2 large reinforced metal cutoff wheels with appropriate mandrel to hold them; 3 standard grinding wheels; 7 flat sanding discs; 1 wire brush wheel; 1 grinding/sharpening drum; 1 drywall type router cutter; 1 small ball shaped engraving burr, 1 narrow cone shaped silicone carbide grinding attachment and 1 small block of polishing compound.

I think that amounts to about 30 accessories and it is a good basic kit to get you going. Through my use of other similar rotary tools, one other specific accessory I would certainly suggest buying from the start is a flexible shaft attachment. This connects to the Dremel and provides a smaller pen-style hand-piece with collet on the end with which you can attach bits for much finer and more precise control of the tool. This is essential for finer work, hobby or model making or engraving of personal items and goods. It makes using the Dremel more like using a high powered pen than using a large powered bologna (un-sliced), if you know what I mean! The Dremel 4000 6/50 kit does come with the flex shaft attachment in that kit, so that may be the one to go for if you think you will be using your Dremel 4000 for more precise work.

The kit comes with a wrench to add and remove bits from the collet. To lock the shaft to help tighten or loosen the collet, there is a shaft lock button near the nose of the tool. Just hold this in and rotate the collet by hand until the button locks the shaft in place, then while holding the shaft lock button down, use the wrench on the flats of the collet to loosen or tighten the bit. Immediately behind the shaft lock is the main ON/OFF power switch. This is a slide type so you simply slide it forward to power on the Dremel, and slide it backward to power down the tool.

If needed, there is easy access to the brushes for the motor on both sides of the case. If you need to replace the motor brushes, they can be readily accessed here with a flat-head screwdriver, or you can use the reverse end of the collet wrench which will also do the trick. Usually these don't need looking at often. perhaps once every couple of years, but if you are using the tool for long periods almost every day, you might need to check them more frequently, perhaps a couple times per year.

The Dremel body itself is overwrapped in crucial gripping areas with a rubber covering for comfort and increased grip. It is sized to fit in the hand comfortably, but for precise work, the flex shaft attachment is a better option for greater control. There is also a metal hanger incorporated into the body which allows the Dremel to hang from a hook. This is especially useful when using the flex shaft accessory (sold separately). Well, that about wraps it up for the tool's features, now let's see how it performs various tasks using the array of accessories and bits included in this particular 2/30 kit.

Usefulness and Effectiveness
Let me first start by saying that I happen to use this tool most for hobby work on RC planes and for grinding type work in home renovations. In particular, grinding off nail heads during reconstructions where the nail cannot be easily removed, hammered into a surface to hide it, or no other tool can get into the right spot to grind the nail flush. During re-fits and renovations, this problem seems to pop up quite a bit. The Dremel and similar rotary tools are the perfect answer for this. Using the cutoff discs you can quickly take the head off a problem nail pretty much flush with the surface the nail was driven in to. The small grinding or cutoff wheels can be consumed quite fast however so a good supply of them is needed if you have a lot of nails to chop the heads off, particularly with large framing nails where you cannot easily snip the heads off with other hand tools. Luckily, accessories for Dremels are found just about anywhere and while the Dremel brand is recommended, you can get other branded accessories and replacement wheels or discs to fit quite readily. The quality of these is a bit hit and miss sometimes... One batch you buy from a certain brand may he horrible and useless, but the next might be great, so it can be a bit of trial and error when it comes to finding a good, affordable supply of spare accessories and bits. I buy my grinding and cutoff discs from a local builder's tool merchant where I can buy them in 100 and 200 lots. Another neat trick too if you find you are snapping a lot of the small and thin cutoff wheels is to mount two wheels together on the mandrel and ensure they are secured well. Don't overtighten as this can crack them but make sure they are tightened fairly firmly. Running two cutoff discs adds extra strength and they will cut off twice as many nail heads, but of course you are using twice as many cutoff discs too so it evens itself out. Naturally, the larger reinforced cutoff discs supplied by Dremel in the kit are much less prone to snapping or breaking when undertaking this type of task and are the preferred cutoff wheel if they are readily available locally. And while we are talking about cutoff wheels, these work equally well in many other small cutoff tasks. I wouldn't attempt to cut a thick steel pipe with these as it is simply not practical and you will chew through a large number of discs trying to do so (but most likely you will quit before you even get close to cutting through). These large scale tasks are best accomplished with a proper 4" or larger grinder. But the Dremel is great when it comes to cutting aluminum angle for wall plastering, cutting angle for tiling edges or corners, and for cutting any thin sheet metal type extrusions or fittings. It is the perfect tool for those jobs where a larger grinder or cutoff tool is overkill for the task.

Onto sanding... And while some of the application photos shown on Dremel sites and in marketing brochures show a Dremel being used to sand large items like chairs or base trim/moldings, this is ok if it is just a small area being worked on but I couldn't imagine how long it would take to sand an entire house work of trim molding using a Dremel. It is simply not practical for large scale stuff. What it is good for when it comes to sanding is smoothing off puttied corners of trim, carefully sanding off small globs of paint or paint runs on wall edges or faces, sanding plastic or wooden model glue seams, and the list could go on. Think practically, and if the task doesn't call for a large tool to practically complete the job, chances are the Dremel will fit the bill.

Next up is polishing. The 2/30 kit comes with two polishing wheels, a mandrel to fit them on and a block of polishing compound. Again, don't expect to polish your car with the Dremel (could do it I guess but certainly not practical), but for jewelry (not fine jewelry where parts could get broken off), polishing small wooden parts after varnishing, or getting into corners of large wooden furniture items like chairs to buff wax off, the Dremel is the tool suited for these tasks. On my wood lathe I often make wooden slimline pens as gifts, and for very special ones where I am after a very high shine, I can polish the barrel surfaces using the Dremel with great results. The polishing wheels do work quite well.

Engraving... it's amazing to me how much of a need you have to engrave stuff when you get a tool that can actually do it. At home we engrave all our valuable electronics (TVs, DVD Players, Home Theatre etc) with special identification codes that allow the items to be tracked back to us via the police should they be stolen and later recovered. The small ball grinding/engraving bit in this kit works well for that task. Or it can also be used for very delicate shaping of wood or sign-writing in wood. I found a use for it to shave a slight amount off one of my R/C balsa wood aircraft models to aid in better balanced flight.

The drywall cutter is like a drill bit and router bit in one. It is primarily used to plunge into drywall sheets and then rout out a section of the drywall to accommodate light switch fittings or power outlets etc. It replaces the jab-saw or plaster/drywall saw for this task. It can do it much quicker too and usually a lot cleaner as well in terms of the cut edge... manual saws tend to rip at the outer paper layers of the drywall, whereas the Dremel with the drywall cutting bit leaves a much cleaner edge. As a matter of fact the #561 bit is a multi-purpose cutting bit which can also be used for cutting plastics and wood etc. I found it works ok on thin plastics and thin acrylic with care. On harder woods however it didn't seem to cut terribly well, but it worked very well on balsa wood for my model aircraft.

The wire brush included appears to be the carbon wire type. These are good for general cleaning of metals in hard to reach spaces or for fine work. I don't personally often have a need for a wire brush this small, however, I have noticed of late that they can be quite useful for cleaning off silver solder and around soldering joints for wiring. It is interesting the number of tasks you find the Dremel is indeed useful for. The more you use it the more tasks you seem to find.

The red/brown drum shape grinding bit is made from aluminum oxide. I seem to use these types of bits quite a bit with the Dremel and my other rotary tool. They come in very handy for cleaning up small joints joined with an arc welder that tends to spatter at times, and are great for de-burring cut metal, particular that which has been sliced with a grinder leaving a sharp edge. Another great, and perhaps the best use for these small grinding stones is sharpening. While I sharpen by woodworking chisels using a bench grinder or slow speed grinder, the Dremel stones are excellent for scissors, knives, and mower blades among others. One Dremel attachment I have owned for many years which I use on my other rotary tool is the Dremel chainsaw sharpening kit. This comes with specially sized grinding wheels and a jig to set them at the right angle. It is great to quickly touch up chainsaw cutters without having to take the chain off the saw and refit it later. But with the included drum type stone included in the 2/30 kit, I can quickly touch up my mower blades and most cutting blades with good accuracy and ease.

The last bit in the kit is a long cone shaped green grinding stone. It is made from silicon carbide which is tougher than aluminum oxide. It is designed for cleaning on hard surfaces such as glass or ceramics. Since I have never really had a need for that I haven't used it yet and won't comment further. I did read somewhere though that champagne glasses should have a little scratch/scuff marked in the bottom of their champagne glasses to get that constant flow of bubbles from the bottom of the flute. Apparently the bubble like to form on these raised points? The oddest things you read sometimes eh? I suppose you could use this bit to make that scratch if your flutes seem bubble-less but don't go wrecking some nice glasses without getting permission from certain others first (if needed)!

And now onto the major accessories included, of which there are two. The first is a circle cutting jig with removable straight edge guide. As the name suggests you can mount your Dremel 4000 onto this jig and use it to cut out perfect circles with appropriate cutting or router bits. The applications here could include cutting wheels out of thinner boards for toys, cutting circles for various art, making small lazy susan tops, or mechanical parts for wooden machinery (and possibly metal too with the appropriate cutters) and so on. Another practical use is cutting accurate circular holes in ceiling plaster to fit halogen or low-voltage downlights. Remember that while this attachment is useful, it may not be suitable for cutting holes in very thick materials. Because the holes have to be routed out using the proper router bit (or drywall bit for drywall cutting) you may need to make multiple shallow passes instead of one deep fully penetrating cut. It is best to make multiple shallow passes because you wont dull your bits very rapidly or burn out the Dremel motor from excessive load. The Dremel screws into the circle cutting attachment (after removing the nose housing cap from the Dremel itself) and it all attaches firmly and securely to the jig. The jig has a pin assembly which can slide along the attachment bar to allow you to cut different diameter circles. There are markings in metric and imperial along the bar, and you will notice two sets, one on each side of the bar. One set is for the circle cutting scale and the other for the straight fence attachment. The circle scale is actually referenced from the securing screw that holds the pin plate in place on the bar, not from the pin itself, so if you need a very accurate circle or disc it may be better to measure on the material itself and then set the Dremel with circle cutting attachment to those measurements, because there can be a bit of ambiguity introduced by measuring off the securing screw because of its diameter. If you use a different diameter cutting bit too then manually check offset for the pin to create a circle cut to the diameter you exactly require. The depth of cut with the attachment can also be adjusted via a scale as the Dremel sits in a locking sleeve that is height adjustable and comes with an integrated scale. This is handy to quickly adjust the cutter for a pre-determined depth in multi-pass routing or cutting applications, but this scale too also requires that the cutter be set in the correct depth in the collet for scale accuracy.

Along with the circle cutting attachment comes a straight fence which attaches to the same assembly. This allows you to cut or rout small grooves parallel to an edge and works in the same manner as a router fence, jigsaw fence or circular saw guide fence might work. It is good to see the straight edge guide and circle cutting attachment designed and bundled together. It works well in small scale cutting applications.

The other attachment included in the 2/30 Dremel 4000 kit is a sanding and grinding guide. It attaches in the same way as the circle/straight cutting jig and has the same height-adjustable locking sleeve to project the grinding or sanding drum a pre-measured distance below the face of the guide. This guide has both a 90 degree and 45 degree face and comes in handy when you need to grind or sand an edge that is either 90 or 45 degrees to an opposing edge or face. If you take a look at some of the application photos included here, you will see what I mean. I didn't personally find a lot of use for this particular jig as most of my right angled or chamfered edge sanding or grinding work is done on larger scale projects where other larger tools better suit, but again, I am sure in the future that I will find a new use or task where this particular attachment comes into its own.

The whole kit comes shipped in a grey plastic storage kit and everything fits back into it fine after you take it out the first time (fancy that).
The package lists a 5-Year limited warranty.

I have read in some other user comments that they have had difficulties with the Dremel 4000, with motors burning out or switches ceasing to work. Luckily I have not had such problems. I am not sure whether it is the tool or the user at fault here. It is interesting to watch other people use power tools in general, and it is not surprising why some of these people seem to suffer tool failures more than others. Many people overload a tool's motor during use, in most cases not knowing any better, and when it breaks, they blame the tool. Power sanders are a prime example. I can't count the number of people I see trying to force a power sander onto a surface to make it sand faster. Doing this in most cases actually makes sanding slower, and they should instead use a new sanding pad, or one with a coarser grit, but they continue to overload the motor with excessive force and you can hear the motor screaming out for relief! The same applies to power cutting tools and dull or blunt blades. The motors are put under more load when trying to cut something too fast with dull or poor blades. With this in mind, I can say that personally, my Dremel 4000 has yet to show any sign of failure or any other issue. I am quite vigilant to ensure no excess force is placed upon the tool. If it isn't doing what I want it to do (within reason), I look for the answer that doesn't place undue load on the tool... and that is, use a new sanding disc or drum, dress my grinding bits, use a new blade, or realize the tool may be too small for the task at hand and look for something more appropriate. In fact, in my many years of power tool use, I am happy to say I have never burnt out a motor on a single tool, even some very cheap ones. I am not gloating at that fact (although my wallet certainly appreciates it) but I am trying to make a point to help you save money, time and hassle. If you look after your tools and don't try to undertake a task they aren't designed to do, the tool should last quite a while. Sure you can get defective tools, but in my experience these are quite rare these days and I have seen the people burn up motors right in front of my eyes, filling room with noxious burning smells and I am not one bit surprised why, but they seem to be!! Keep your gear clean, and in good working order, carry out any scheduled maintenance it may require according to the manuals and you should find your power tools lasting for a good many years.

Now, with that said, let me get onto the conclusion... The Dremel 4000 has been a great and handy tool so far. It doesn't suit every application, and some tasks will be way beyond the practicality of this tool, but for those tasks it can and should be used for, the Dremel 4000 has so far undertaken those with ease, and done it well. The Dremel 2/30 kit as reviewed here retails for around USD$79.99.  

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Dremel 4000 Photos
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The Dremel 4000 Rotary Tool

The ON / OFF slide switch with shaft lock button forward

The metal hanger can be used to hang the tool for use with flex shafts, or for storage if needed.


The variable speed control dial shows more accurately what speed the tool is running at.

One of the included grinding bits mounted in the Dremel collet ready for use.

The accessory kit included with the
Dremel 4000 2/30 package.

The sanding/grinding guide attached to the Dremel.
Note the depth adjustment sleeve with scale.


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