I purchased a DeWalt 12volt cordless drill with two 'dead' batteries from a guy on eBay for about $10 (£6).
I intended to turn it into a corded drill as demonstrated in several Instructables.
Then the project seemed to take on a life of it's own and I found myself adding new features and enhancements.
The end product is a super drill and an amazing before and after project.
I have set out each improvement separately so that anyone reading this may select to do any or all my suggested improvements.
Step 1: In the Beginning
I started with this fine pedigree drill that had served it's owner well for many years and was now looking a little tired.
I wanted to give it a new lease of life.
Step 2: Tools
I would need a wide array of tools but nothing super special that is not owned by the average tinkerer.
I set to work removing screws and opening up the little beast.
Step 3: Ready to Start the Refurbishment
After about 15 minutes, I had all the parts separated, and the small parts safe in a container.
The first job would be to clean the plastic housing and then to check and clean the inside components.
Step 4: Grime Time
The drill casing was extremely grubby. It was coated in all sorts of oils, grease and grime.
I tried the dish washer, which helped a little, and then went through each and every cleaning product we had in the house.
Eventually the casing was 'acceptable' but it was not possible to return to an 'as-new' state.
Step 5: Turning Back the Years
The motor and gears etc were in fairly clean condition.
A few minutes with a brush and a few Q-tips had it in a relatively clean state.
Step 6: Removing the Old Brushes
I had managed to get a new set of brushes from a local DeWalt dealer for about $8 (£5).
I had shown him the originals and he 'matched' them.
I then put the old ones back in, to take these pictures of how to remove them.
I had originally been baffled as to how they came out. In the end I found a YouTube video for a similar drill that answered my question.
It really is simple...you just insert a flat screwdriver between the metal housing and the plastic of the brushes, and lever gently. The whole assembly then pops out.
Step 7: A Commutator Clean and Then New Brushes
Once the old brushes were out, I took the opportunity to clean out all the accumulated crud.
I carefully cleaned the carbon deposits from the commutator and around the inside.
You may see from the image above that the old brushes were not in desperate need of changing.
It was still best to put in new ones whilst I had the drill apart.
The new brushes simply slid back into place with a satisfying click.
Then I noticed a problem....
As you may see the last image above; The old set had a spade terminal on the brushes to take the bladed connector from the switch, which meant I could not simply slip in the connectors again.
I solved this by carefully disconnecting the connectors from the old brushes and replacing the spade ends on the switch wires. This worked well.
Step 8: Adding a Belt Clip
Many of the latest drills include a shiny belt clip and I wanted my new friend to have one too.
It is possible to buy genuine DeWalt clips for about $8 (£5) but I had a suitable clip from a broken tape measure that was ideal.
I had actually done a little balancing test with the drill, before I disassembled it, to find the centre of gravity and therefore the best angle to have the belt clip.
Inside the case there was a moulded raised circle that seemed a great place to make the hole for the securing screw.
I just used a brad awl to make the hole and then inserted in the retaining screw.
Next I mounted the clip, which uses a sort of keyhole method to enable it to go over the screw head and then slide down into place.
When I checked the other side and saw that the screw protruded a very long way and would touch the motor.
I placed the screw into the chuck of a drill held in my workmate vise. Then, with the drill running, I moved a saw blade along the screw to cut it back. This was the quickest easiest was to ensure that the screw was evenly cut back.
Before the screw was cut all the way through I re-inserted it into the drill case. That enabled me to screw it back tight. Once it was in position and the clip was secure, using a pair of end cutters, I trimmed it to length. (I had tried just cutting it before but that was not feasible until reduced in diameter)
Finally I covered the inside part of the screw with a sticky felt dot to insulate the end of the screw. I then tested all was well. (I have included a picture of the finished refurbished drill hanging on my belt).
Step 9: Mounting the LED
Having decided to have a built-in light, I used a super bright white LED.
I had this in my spares box but they are readily available on eBay,or from electronics suppliers etc.
I 'eyeballed' the possible location at the front of the drill. I thought that it would be tight.
It would not be possible to insert the LED from the back and the little step at the end of the LED, would prevent insertion from the front.
I solved this by 'gently' fitting it into a drill chuck and then holding a file next to it whilst the chuck rotated. (The drill was held in my workmate at the time).
The LED could then be inserted from the front.
Because the hole drilling had to be very precise I started the process using a hand drill before using the correct sized (5mm) bit.
Everything worked out well and the finished appearance was clean.
Step 10: Wiring the LED
I first worked out the spacing and positioning of the resistor, noticing that it would not be able to be inserted from the front and would have to be attached in-situ.
I first soldered it to the Anode lead (The longer lead of a LED).
I actually used the method taught me many years ago when I worked on defence contracts. I noticed recently that there was an entire 'ible on just this connection method (You can check it out here...and it is fine example of how to use a great title to get attention for a simple 'ible)
I placed shrink wrap over the first section and then slid on another piece after soldering the hook-up wire to the other end of the resistor.
I was worried about using the huge hot heat-gun close to the plastic, but I kept exposure to a minimum and so there were no adverse effects.
Finally I routed the wires safely and locked everything in place with hot glue.
Gluing the LED at the correct angle and position was essential and so I held it for an extra long time to ensure that it would be fixed correctly.
Overall this was a fiddly and awkward procedure but all worked out well.
Step 11: Ooops.... Need to Switch the Switch
I had tried the switch in the position, checking that it did not obstruct the motor unit. However I must have had the motor incorrectly seated or was blind...as, when I tried it again after drilling, it was not a good fit. There was not enough clearance at all.
I tried bending back the switch tabs but that was not enough. The only solution was to re-locate the switch.
You may notice in some of these images that the switch appears at the rear bottom. The wrong switch location images are because I completed those stages before I noticed the issue.
I filled the hole with Sugru and re-mounted the switch higher up and off-set to the right.
I checked and double checked there was enough clearance.
Perhaps I could have found a smaller switch but this one had the correct rating and looks good externally.
I wanted the switch to be 'on' when down and off when up. A few minutes with the meter sorted out which connections to use. Since it was a double pole switch I wired it to switch both connections.
I worked out wire length and then took out the switch to solder up the connections.
This was extremely fine work and I had to work hard to ensure that the wires did not short.
Once done and tested the switch was locked in position and hot melt glue was put over it as extra insulation.
Step 12: Keeping Things Level
The image above shows my first attempt at incorporating a bubble level into the design.
I moulded Sugru around the bottom of a bubble level and stuck it on top.
It looked hideous. Plus it was very hard to use.
I then bought some little bubble levels from eBay for a few pennies (This is the same thing on Amazon).
These turned out to be just what was needed.
I was very careful to ensure that the bubble was dead centre when the drill was level.
Note: If you do not want to drill your drill, then it would be possible (and just as useful) to just stick them on the outside of a drill using Sugru or even double sided sticky tape..
Step 13: Fitting the Top Bubble Level
I located the flattest central spot, marked it and used a hand awl to ensure that the hole started in the correct place.
First a pilot hole and then the correct size hole was drilled using a step bit to drill an 8mm hole (other bubble levels may vary in size).
Finally I glued the level inside using polystyrene cement. It was only glued on one half of the shell to enable it to be opened in future.
Step 14: Installing the Rear Bubble Level
I marked the centre of the rear, and checked that there was nothing on the inside that would be adversely affected by being drilled.
The shell was then clamped in a workmate type vise and also a C clamp was used to ensure that the case did not part as the drill entered.
First the pilot and then the correct sized hole were drilled.
The bubble was a good snug fit into the hole.
As before, I glued it on just one side to enable the shell to open if ever required.
( Note the position of the switch shown at the bottom was later moved).
Step 15: Modifying the Switch Housing
I removed the drill power switch from the black plastic housing.
I removed the copper heat-sink using a star bit.
I checked a few possible routes for the new cables and decided that, with a little 'plastic surgery', the new external power feed cable could run down the spine of the plastic cover.
I cut out some parts with a cutter and filed out channel. This neatly contained the cable, keeping it well out of the way of the battery pack. Later I dropped a little hot glue on to keep the wires in the channel.
Step 16: Cabling for the External Power Feed
I had decided that the external power would not go in via the battery as in other Instructables.
I wanted the drill to still be able to function normally and I wanted to be able to use my external feed to also charge an inserted battery.
I was also going to run the LED in parallel direct from the power in, and so needed to connect those leads at the same time as the power feed.
I briefly considered connecting at the top of the switch but realised that in use, polarity could be reversed and the voltage varied by the drill control.
I measured out a length of 10 A cable for the power and also some lighter hook-up' wires to go to the LED switch.
With the heat-sink removed there was easy access to the copper connectors and a big pad to solder on to. I scraped clean the pads, tinned them and then soldered pre-tinned cables to the pads.
This was not the ideal connection, as it has no mechanical strength, but since there would be no force acting on these cables it was an acceptable solution.
Once the connections were complete and tested I replaced the copper heat-sink.
Next I estimated the length of wire needed to reach out of the drill and connected the 2 pin connectors.
Step 17: Connector Notes
I used the 2 pin connectors generally used for LiPo battery connections in model race cars.
They have several names such as LiPo connectors, Race Battery connectors and Tamiya connectors.
It is a good connector as it can handle high'ish currents and locks together.
There is a male and a female housing.
To 'confuse matters' the male connectors go into the female housing and the female pins go into the Male housing.
Positive is usually red and goes to the Square hole pins and Negative, black, goes into the Semi-circle shaped receptical.
The wires can be simply crimped into the pins but I prefer to also solder them.
Once inserted into the housing they cannot be removed. This would have caused me a problem, as I had a bad joint. Fortunately, I had tested each connection before insertion and so avoided having to replace the whole connector.
I definitely recommend testing (and wiggling the wires) before insertion.
The 'convention' is that the 'female' part is on the device and the 'male' part is on the battery or power supply.
The other end of the external power lead was connected to a standard Car accessory plug.
(Is that the world's ONLY universally available, international standard plug?)
The outer is negative and the inner pin is positive.
Note, the original fuse I used was only 3 amps and it failed. So I had to use a 5 amp fuse.
Step 18: Adding a Depth Stop
I used a tent peg , the end of a ballpoint pen, an electrical connector, and a screw to add a very useful new feature to the drill.
Step 19: The Drill Depth Stop
I often used sticky tape around the drill to tell me how deep to go.
I actually do own some metal collars that fit onto bits, that can be set to any depth, but I can never find them when I want them or they are for a different size of drill bit.
Those days are now behind me since adding this simple but effective drill depth stop to the side of the drill.
I actually investigated using a row of magnets to hold the steel rod, but when it hit the wall it just slid back and provided no limiting effect.
Next I considered building a holder using PolyMorph or even Sugru, but in the end I used my trusty brass connectors.(As I used in my very first Instructable)
By cutting the mounting hole back a little and using the plastic top from an old ballpoint pen, I could use one of the existing holes on the drill to mount the assembly.
I used the steel tent peg (10 for a dollar or pound) as the stop bar.
I cut the length of the bar to the maximum I could whilst still having it stay within the length of the drill body. That was to avoid the potential for being poked in the eye during use.
I checked it with a range of drill bits, including long Spade bits and all could usefully be used with the depth stop.
This simple addition could be added to any drill by adapting the fitting to suit.
Step 20: Final Touches
Of course I could not stick the old label back on my 'spiffy' drill.
So I booted up Photoshop and, after downloading a few images and creating a new label design, I was happy to print it out.
I printed it on stiff paper and then laminated it. It is only stuck on using sticky-stick (Pritt stick) but so far all is good.
I can always produce another one if it gets damaged.
I love having the robot as part of the design and I can claim to have a totally unique drill which is truly a Special Edition.
Step 21: Bring Out Your Dead
I was always intrigued by Instructables such as this one in which he revives old cordless batteries using a welding power supply.
I would have been happy using my refurbished drill with my 12v power pack, but I had to try the Lazarus effect on my dead batteries.
I first tried to charge each normally and after 24 hrs the results were as seen in the first images, just a few volts.
I then used a 12v Jump start pack connected +Ve to +Ve and then tapped the -Ve to -Ve connector about 30 times at about one second per tap. I got tiny sparks (that do not show on the photo).
I then charged the cells up for about 6 hours and checked the voltages.
Wow... they were over 12 volts.
(I know that just seeing a higher voltage does not necessarily mean that there is enough energy to deliver sufficient power to the drill, but it certainly shows promise of a possible improvement).
This method certainly worked for me and the batteries work fine in the drill.
(One lasts a little longer than the other but both are usable).
Extra Note: (Added 7th August 2015)
I read that taking a dead battery and 'banging' it down hard a few times, would also loosen the 'dendrites' that affect the battery functioning. I tried this on the battery that had not responded so well to zapping ....I thwacked it down onto my long suffering workmate bench about a dozen times, and the result is a fully charging, long lasting battery.
I can now recommend also trying a few healthy bangs to revive 'dead' NiCad cells.
(Of course you should be careful when, where and how you bang your batteries).
I will now be trying BOTH these revitalizing methods on all my other cordless battery packs.
Step 22: A Tour of the Finished Drill
I am VERY pleased with all the improvements to this drill.
The external power connector is very useful and in fact I am now using it to charge the batteries. Those batteries were of course revived using the reverse voltage zap trick.
The drill depth limiter is also extremely useful and is far better than my old sticky-tape-around-the-drill method.
I do not actually use the belt clip much since I feel a bit of a 'poser' wandering around with a my macho DeWalt hanging off my waist like a 12 volt gun slinger. However it was of huge benefit recently whilst I was at the top of a ladder and needed to drill. Being able to store it temporarily on my belt, whilst I used other tools was a big bonus.
The most generally useful addition has to be......drum role please...
Step 23: Let There Be Light
The super bright LED light ...that is just amazingly useful.
Even in daylight I find it useful to more clearly show where the drill mark is.
I have even used it as a torch (flashlight) to rummage in the darker recesses of a tool box.
I definitely recommend anyone to upgrade their drill to have lighting. If you cannot do it as an integrated fitting then maybe THIS INSTRUCTABLE which uses Sugru, magnets and little LED key-chain lights, will good for you.
So, that is it, dear Instructabler, one of my longest and most image filled Instructables.
I suppose each could have been done separately to produce 3 or 4 separate 'Ibles. So you have extra value in this one.
I do hope that you are inspired to do at least one of the upgrades that I have described.
I am certainly happy with my 'cheap' drill after investing a little sweat and time.
I do hope you all agree that it represents a superb Before and After project.