Portable Dremels are surprisingly good and in spite of the battery they pack a lot of power without the burden of having to have a power source when using the tool. The Dremel 8240, for example, is just about a hundred bucks and is delivered with some sample tools, a charger base and the Dremel itself.

The build quality is as usual excellent but for some reason there is some sort of hiccup in the design of the base and charger that is rather stunning considering that the Dremel itself is perfect. The charging base is connected via a non-detachable cable to a power converter that steps down mains power to but there is no way to detach the cable at all. The charger itself is a run-of-the-mill AC-to-DC converter with an additional stepdown to such that the charger could be easily replaced if need be without messing with the charging base but for some reason Dremel delivers these two connected together with a cable.

Refining the build seems to be fairly straightforward; the charger base has to be opened up, the cable removed and a power jack added. One additional limitation as you can see is that with the base and the power transformer connected, if you are travelling to a country with a different outlet format, you'd have to buy the whole base and charger or get a converter that makes the whole thing even more bulky and wobbly, hence even more unreliable during charging.

The inside of the charger shows a very simple build with a cable coming into the base from the side and a PCB that provides the charging circuit for the battery. The PCB looks very good and it is clear that this is a premium device; there are no cold solder joints, the circuit looks tidy without pulling leads allover the place and the PCB itself seems like it is out of a resistant material. Furthermore, all the components are surface mounted and tantalum capacitors seem to have been used for the design, making the PCB and therefore the base itself a quality design that will last forever.

The top side of the PCB shows the two wires from the transformer connected to the PCB and held in place by some malleable rubber. The rubber can be easily removed thankfully without leaving any residues in order to remove the wires from the PCB. With the wires removed, another look is taken at the power transformer.

It truly seems an unspectacular transformer that could and should be easily replaced in case it fails without really having anything to do with the Dremel base.

The PCB is then cleaned around the contacts where the new wires will be connected.

Similarly, the Dremel itself is used to drill a hole into the base in order to be able to fit a power jack. Interestingly, there is a lot of space inside the base so it is very easy to get the hole right and centered. First, a small hole is drilled which is then enlarged using a hard sanding bit in order to obtain a perfectly round result.

The base seems to have some extraneous plastic struts on the inside but intuitively these are more than likely there in order to strengthen the overall structure of the charging base. Unfortunately, without starting to hack at the plastic inside the base itself, and even though the power jack fits well inside, the jack will have to be secured using a bit of epoxy glue to not fall out. A two part epoxy is chosen that can be removed by applying some pressure if the need would ever arise.

The wires are first soldered onto the jack pins and the cable is passed through the whole when the power jack is fitted in order to not have to hold the base cup upside down and solder like that for the sake of not burning the plastic. The wires are then connected to the PCB by respecting the polarity - conveniently, the PCB has writing that indicates the positive and negative.

With the PCB connected, the two screws on the back are fitted and the base is reassembled together.

Connecting a jack to the base and supplying seems to light up the base perfectly.

Another usefulness that comes to mind regarding this Dremel modification is that this is a tool that will end up being used at the workbench and it is clear that there will be other tools as well. If every single tool would want to have their own power transformer, the power usage will be sky high, there will be a lot of EMI generated and cable management will be a nightmare.

Incidentally, in this case, the Dremel is mounted onto the wall, using some hot-melt glue (which seems great for a non-heavy semi-permanent bond) and then powered using a split jack that also powers a bunch of other devices as well, which is great considering that this is really just a charging base and shouldn't even be permanently powered, especially with a huge bulky power transformer buzzing away for no reason.

The Dremel is great, a quality rotary tool that is indispensable and well-built. To be fair, the cable that hard-connects a simple power transformer to a great charging be is a genuine design brain fart on behalf of Dremel. There would be so much more value added if the charging base would be socketted like this mod realized and it would allow people to use any step-down transformer they like. In fact, the old transformer can now be used separately or a male jack fitted so it can be used with the base.