Cordless Drill Upgrade for About $40




save hundreds on a drill by upgrading the power to 1.4 hp instead of buying new.

I needed a cordless drill to do some outdoor drilling, but I did not want to spend $200-$300 for a 18v-24v cordless from a store shelf. I got a cheap 6v cordless drill that I up graded by replacing the motor, the circuit ,the batteries; and I made box to hold the 16 C batteries. After the fabrication and assembly, I tested it and found that it was almost as powerful as my 120v AC corded drill from Skil. The price of this project would be $30 for the parts, $8 for the alkaline batteries, $40-$70 for nickel cadmium rechargeable batteries.The price depends on the quality of the drill I started with which would cost around 30$. If you have to buy an inexpensive cordless drill, and do this conversion, it will still be cheaper than an expensive cordless drill.

Please note that the photos are in mirrored image.

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Step 1: Tools and Parts List

the tools include :

1. soldering iron
2. circle guide or compass
3.solder (I suggest lead free)
4. electrical tape and masking tape
5. screw drivers
6. alligator clips
7. wire strippers
8. small hammer
9. red and black markers
10. drill
11. pliers
12. ruler
13. scissors
14. hand saw
15. file
16. pliers
17. wire cutters
18. super glue
19. volt meter or you could use a battery,
light bulb and wire instead to check conductance
20. drill bits
21.sand paper

22. hobby knife

parts include:

1. a metal or hard plastic box
2. metal sheet (I suggest aluminum)
3. battery holders
4. 24 volt motor
5. electrical connectors
6. insulated wire
7. small plastic box from an adapter
8. steel wire
9. 16 batteries
10. 4 button
11. coat hanger
12. CD box

The 1.4 hp motor it is normally used for RC cars, I got this one at a local hobby store for $10, if you can't find it locally you can get it at

I found a good source for rechargeable battery's at I suggest
that you only use nickel cadmium batteries because they can be charged easily, just supply power of 1.7V multiplied by the number of 1.2V batteries, connect in Series or 1.7x) other batteries need a more complex charger.

The four buttons on the second slide of this page are not the same. The two blue buttons are on when at rest and off when pressed and the two red ones are off when at rest and on when pressed.
This will be explained later .

Step 2: Disassembly and Modification

The first thing to do is to remove the screws on the drill, then take notes on the inner workings, this is important because you might not have the same drill. Remove the batteries because they might be leaking corrosive or toxic chemicals so take them to a poison control office or hardware store where there should be a bin for old batteries. Next remove the gear from the motor and leave the switches intact because they will be used later. Then finally cut away from the base because you will need to make space for 1 battery and the connectors. Now you have all the salvaged parts.

Step 3: The Battery Assembly Wiring

Here we will make the battery circuit and some of the attaching assembly.
Start by stripping the insulation on all the wires, then cut the wires on one of the battery holders then cut the battery holders. Connect all the battery holders into two sets of eight battery circuits. Place electrical tape on all the connections and place all of the battery holders in the battery box except for one. Trace the bottom of the drill then use another drill to make a quarter inch hole in the top of the battery box after removing the lid from inner components. Place the lid back on then feed the four wires though the hole. Place a connector on three of the wires and the fourth being connected to the last battery holder, then to the fourth connector. Be sure to lablel the connectors , remember there are two separate 12V circuits.

Step 4: The Battery Assembly Connecters

In the last step there was one battery holder outside of the battery, now you will make a smaller battery box out of aluminum. Start by making a paper model and check if it fits, then copy it in aluminum. The drill might require a spacer, so I used the converter box as a template to make one out of plastic, then used super glue to secure it. The final part is to drill some smaller holes and make a loop with some metal wire then use super glue to secure it.

Step 5: Clamp Asembly

In the last step there were four metal loops on the battery box that will be used to attach the drill to the battery box. Start by drilling the holes in the bottom of the drill then place some metal loops much like the last step, then make some clasps similar to the ones on a briefcase out of wire.

Step 6: The Mechanical Mechanism

In this step I placed the small gear on the motor then used a small amount of super glue. The plastic shell has rubber pads so the motor does not need to be glued in place. in my case the motor shaft and the motor was the perfect size, but if the shaft on the motor is too small you could add a small brass tube. If the shaft is to big you could drill the gear to make the hole bigger but if the hole is too big the gear will break apart. If the motor is too small then you could put a piece of pvc pipe around the motor so it will fit. If the motor is just slightly smaller then you could wrap the motor with paper and tape.

Step 7: Electronic Mounting

Remember the four buttons, the two blue ones are on when at rest and off when pressed, the two red buttons are off when at rest and on when pressed. These will be placed in this step
where we will be mounting the buttons in the shell of the original drill. The red button in the back is used to turn the motor on and off, and the other red button as well as the two blue buttons will be placed at the trigger arranged so that they will move as one and be used to change the voltage from 12v to 24v.

Step 8: Wiring

The first eleven images are about how to attach the female wire connector to a wire. Start by removing the metal insert then strip off the insulation and tie the wire to the metal insert. Then clamp the back end of the metal insert to secure the wire and finally put the plastic tube back in place.

This part is fairly simple but this can be frustrating if you don't know how the wiring is arranged. If you are uncertain with circuitry then I suggest that you follow my instructions exactly. if you are good with circuitry then you could make your own circuit.

Take note of of the battery pack, the four leads should be labeled P1,P2,N1 and N2 the P stands for positive and N is for negative, in my case P1 and N1 are connected and will have 12V and P2 N2 are the same but insulated .

For the wiring, refer to the twelfth, thirteenth, fourteenth and fifteenth pages
wile viewing page elven and twelve. Follow the wiring list given. All of the points on the list should be soldered as one in each column on the list .

w1 w 2 w 3 w 4 w 5 w6 w7

P1 N1 P2 N2 E2 M1 M2
C1 A1 C2 A2 D1 F1 F2
B1 E1 D2 B2

Once you have done all of this you might want double check the circuit for shorts or any other problems, then you would have what is seen on the first image.

Step 9: Completion

This is the final step, first put some electrical tape on all connections then put the mechanical components inside, cover and secure in place. Now comes the part you will have to repeat regularly. It is to attach the connectors and make sure that they are labeled, and now you are finished.

If you want to go beyond alkaline batteries and make your drill rechargeable, you need to get some Nickel-cadmium batteries. I suggest that you only use Ni-Cd batteries because they are easy to recharge ,you just supply power positive to the positive and negative to negative (the voltage to recharge is 1.7v multiplied by the number of battery's in Series or 1.7x) Other batteries such as Ni-Mh or especially lithium batteries need a more complex charger.

Whether you get Ni-Cd or something more advanced, you would insert all 16, 1.2V battery or 6, 3.6V lithium batteries (you will need to modify the battery box). Then what you do is to attach alligator clips to the battery leads then to the charger or power supply. You can get an advanced charger at and batteries at or at

Observe the last three images if you are unsure how to charge batteries.

I hope you enjoyed this project, leave a comment or questions and I will try to reply.

the image of battery is from

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    21 Discussions


    5 years ago on Introduction

    Good work. I'll pick up a Hammer Drill, battery & charger at Harbor Freight with a 20% discount which comes to about $47.00.


    6 years ago on Introduction

    Nice! Im looking for a way to power my 19.2 v DC craftsman saw with 120V AC because the battery drains down to quickly if I use it to cut anything bigger than 12" wide... even then i can only get a few cuts... and charging up 3 batteries just to do a small job seems nuts. id rather plug it in when i need to and still use it. Can this be done? Maybe use an old battrey as the "Plug" to plug the power into the saw?


    10 years ago on Step 8

    I assume you realize that 1.4 HP is almost 50 amps at 24 volts (1.4 * 750 / 24)

    That's more than enough current to melt those switches your using, my guess is that as with most cheap motors, its not putting out near what its rated at. Probably more around .3 - .5 HP

    But still, for a drill that's an awesome bit of power :D

    2 replies

    Reply 8 years ago on Introduction

    well, ni-cads put out 1.2 vdc ..
    and 16 of 'em can't make over 19 vdc or so ..
    And 750w/hp divided by 19 is about 39amps, lots less than 50 .. and its only drawing that much current momentarily/rarely , if it ever does!
    And that kind of amperage is a theoretical 'max' but is totally dependent upon the electron source being able to keep up with that demand ..
    What happens in reality is that the battery voltage will drop substantially , and not be able to put out that kind of power ( Iexp2xR).
    Motor specs are very different from power supply specs!

    The point is that your instructable does the job, was well-written, and was interesting to review!


    Reply 10 years ago on Introduction

    It's true that 50 amps will melt the inner components. You would only get 50 amps powering this drill if you hooked it up to two car battery. I tested this by powering it with two 6 A 12 V power Supplies, witch are more power full than 16 c batteries and it only withdrew 2.8 A with the motor staled. I wrote 1.4 hp because it's the greatest output of the motor, if you had a sports car, the manuel would say 300 hp but you would be lucky to get 250 hp. even though it doesn't have 1.4 hp the quote I said earlier about it being "almost as powerful as my 120v AC corded drill from Skil" is true.


    10 years ago on Step 9

    Good work on the instructions, how ever I'll stick with my $180aud 18v Ryobi.... It's gone through numerous brick walls without complaint!


    10 years ago on Step 9

    i just bought an extension cord. a 100 foot one. interesting hack though.

    2 replies

    Reply 10 years ago on Introduction

    an extension cord and a 120 V drill will be cheaper but it is not vary convenient being tied to a plug,


    Reply 10 years ago on Introduction

    It is also not very convenient to have to replace a bunch of disposable batteries plus it looks heavy. I converted from cordless to the 100ft extension method a few months ago and love it. That said, Good hack for the sake of hack.

    why bother with this conversion? 18V drills are now less than $100 bucks at most stores. I can appreciate wanting to recycle old technology but realistically you aren't saving any money here.

    3 replies

    if you all ready have a drill to start with and use the suppliers I suggested or a equal priced local supplier. Then this project will cost $40 for it to run on alkaline batteries, plus $12 to replace them, or $70 for it to run on rechargeable batteries. I ether way it will cost $70 or less.

    why wouldn't you want a drill to run on rechargeable batteries? using regular ones is just terrible for the evoirnment. You can go to HD and get drills for as low as 30 bucks during the holidays


    10 years ago on Introduction

    Very innovative and you should be proud of your work. I hadn't thought of using a rc motor in a drill. On the flip side, I bought a cheap 18v rechargable at harbor freight for 14$ on sale. Regular price is $20. It is a tad slow for drilling through steel, but it runs screws just fine. Granted it isn't as stout as my 279$ 18v Bosch Hammer drill (with charger and 2 batteries) but it got the job done for a few weeks until I could get my old drill replaced. Alternatively I just picked up a Ryobi combo (which are surprisingly good) that came with a drill a skillsaw two batteries and a charger + my choice of one other ryobi tool for $100 at home depot. Of course if you buy one, you loose the ability to tell folks you made it yourself. GS


    check the first slide after the intro and the first item on the parts list, and it will say "a metal or hard plastic box" I used a metal box because I couldn't find a plastic box the right size.


    10 years ago on Introduction

    I love it, too. There is a lot of innovation here. The idea of building a battery box, and the method of attaching it is ingenious. I would never have realized you could upgrade the motor so easily. All that said, I wonder how long this kludge (I use that word affectionately) will hold up...or whether it even matters. The gears, and the plastic housing them, are being subjected to a great deal more torque than for which they were designed. Some reinforcement of the housing is probably possible, but the gears themselves...not. Again, it might not matter. If it was put together for a single use--and it fulfills that need--it was worth it. Sometimes completing the project is it's own reward, if works at all...or if something is learned along the way. In closing; I'd love to hear how well it holds up over time. I'd also like to note that there are more powerful drills (than the original) available for much less than the several hundred dollar figure cited. Check pawn shops, auctions and yard sales for heavy-duty drills which are being discarded because replacement batteries are more expensive than buying a new drill. I have several 9.6v Makita drills which are much better suited to this project than the B&D used. I bought them at pawn shops, with serviceable batteries, several years ago. The batteries are almost all shot at this point. New batteries would cost more than I paid for the drills originally.

    1 reply

    Reply 10 years ago on Introduction

    Thanks for your compliment, as for the strength of the drill, you might have to do some observation of the drill you start with, the one I used had a hard plastic shell along with 3/8 inch thick gears and didn't have any delicate clutch so it's unlikely that it will break. if you are afraid of the drill you start with breaking, you could reinforce the shell by adding steel rods and epoxy, or reduce the voltage. Keep in mind that power tools are often made stronger then they have to be. And as for the price, I will admit the a used drill will be cheeper but you don't know what damages it might have also rechargeable battery wear down over time. Either way you would have to put some thought in to this project, and in my case this project was practical. thanks again for the comment, and if you decide to upgrade the Makita drill you have I would hope to see an image the end result.