Cheap Drill Conversion




About: College student perusing a degree in electrical engineering

This is a super easy way to make your cheap drill run as either a corded or cordless drill, that way you dont have to throw away the battery. It took me about 15 minutes to do it and it can be done with just about any drill.

Step 1: What You Will Need.

Any drill that is battery operated expensive or cheap you wont be damaging it,

A Direct current (DC) power supply the same or greater voltage of the battery, when it is running the drill it will have a considerable drain on it so dont worry if you go over, I did a 24 volt one and my drill is 12 volts.

Wire cutters or something sharp

An alligator clip, one that works well and is got the plastic shield covering part of the clip is best.

A soldering iron, and solder, you will only need if for a minute.

Electric tape.


Step 2: Step One

As you can see with my drill it has 2 different leads coming out of it that would connect to the battery, at first i was going to solder the wires directly to it then i thought just clip them on.

so you will take your gator clips and cut them in half at the middle as pic 3 shows, then you want to strip about 3/8ths of the end of them, get all the plastic off,

do this for both ends, then twist the copper so it will not fray.

you can strip them easily by using the pliers to score the plastic in a circle all the way around then pull, be careful as you don't want to break the copper wires.

Step 3: Step Two

This is pretty easy, all you have to do is attach them to the drill leads and make sure they fit and dont come in contact with each outer. As you can see with mine they fit perfectly.

Step 4: Step 3

now take your ac to dc converter and cut the end off where you would have the round plug make sure not to cut the end connected to the square converter box.

Plug in you soldering iron so it can heat up.

Now take the end of the wire and split it so it looks like a Y see pic 2

Once again you need to strip the wire like you did for the gator clips, and twist it when finished. yours should look like mine in pic 3

Step 5: Step 4 Connecting the Wires.

so now you can take your gator clips and the ends of the power converter, and put them together, like shown in pic 1,

then twist the two together so they are making good contact an wont fall apart.

do so with both clips and in the end it will look like pic 4

Step 6: Step 5 Solder

for this you will need to solder the ends so they cannot separate, you want to do each area that you just twisted this way the gator clips and power supply will be locked together,

Next tape each end separately so there is no exposed wire,

next tape both ends together, this will help them not break form movement.

Step 7: Last Step Hooking It Up and Testing It Out.

This is the easy part

take each clip and put it on a different lead like I did in picture one, it dose not matter which, as your drill will be a dc motor which works regardless of polarity,

next plug in the power supply and test the drill it should run just like normal, two things can go wrong

either you don't have a big enough power supply and the drill runs slow or you have too big of one and it goes way too fast, either way it shouldn't be a big problem you can switch out the power supply or put a resistor in series with it all to burn up excess power.

then unclip the gator clips and hook the normal battery up, it will work either way,

overall this will give you the ability to make a drill work as either a plug in or cordless depending on your choosing

it is a easy and cheap project,

if you have any thoughts or insight or whatever just leave it in the comments and i will read it.

thanks for looking and have some fun.



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    14 Discussions


    1 year ago

    how to make small laser hair removal machine. Like this handy machine or very laser hair removal machine


    3 years ago on Step 5

    Great 'ible - I didn't know you could go over the "rated" voltage of the drill with the supply as I've got a 14v and 18v that could both be converted with just 1 supply instead of two now.

    Only minor thing I would suggest is splicing / soldering the wires together this way as then you won't get that odd kink in the line that can snag and possibly be pulled apart:


    4 years ago on Step 7

    Your instructable is great for illustration and description of the steps, and well done for that. But the theory is completely wrong and you don't yet understand the way this setup (drill or modification) works. If you put a very small engine in a big truck (or maybe just attach a strongman to the front with a rope!) it can be pulled along OK, but as soon as you meet increased resistance it will stop. The DC motor in the drill will free run at a speed set by the applied voltage and when it meets resistance (drilling into something, not just holding the chuck) it will slow, draw more current to try and restore its speed and in doing so it will take more power. If the current source can supply this demand, everything will work as it should, but if it can't then the drill speed will drop and it will stall. In the process you may be trying to take far more current from the supply than it is rated for and its wires, fuses or whatever will melt. I suspect that when you connect your 24V supply it is capable of supplying up to 600mA, which is fine to run the motor off-load. If you measure the voltage at that time it will probably have dropped well below the 24V; if you grab the chuck it will draw far more current than 600mA but for a short time, will not melt. So it looks OK. The limitation on a DC motor is the current through it, not the applied voltage. If you draw too much current through it, it will be destroyed as the windings will overheat.

    As has been suggested, the way to operate a DC drill with an external supply is to keep to the rated voltage and make sure that the supply has enough power to give the necessary current; and connect the two with wires which can safely carry that current. In your case, an old car battery with an in-line 30A fuse and heavy wires would do the job perfectly. Check by looking at the Wattage on the drill rating plate and make sure that the supply has a similar rated wattage and voltage.

    By the way, a DC motor is very much sensitive to the polarity of the supply - I think you may be confusing it with an AC/DC motor, which is not polarity-specific.

    I hope you aren't discouraged by this, it's good to use your resources in innovative ways to save time, trouble or costs; but you do need to understand exactly what you are doing. As my Mum used to say, "A little knowledge is a dangerous thing".

    2 replies

    Reply 4 years ago on Step 7


    I greatly appreciate you taking the time to post this, i enjoy you input, and i understand you concerns/advice, just to clarify about my project

    i think this is key, my project was not designed to work perfectly i did not try to make a perfect match, otherwise i would have done what you had said and use a power supply which produced more amps,
    the power supply i used was the biggest i had, the next was 5v 1A which would not work much better,

    furthermore keep in mind the entire point of this project was to give my old drill (which i got for free) a final chance at use before i got rid of it, the power supply was also free, making this a cost free project for me, which is what i wanted to do.

    Although you all are right the drill is designed for specific current and voltage, they do work with variations of the two, if anyone was to do this project the idea was they could use what they had on hand instead of buying a perfectly matched adapter but then that would defeat the idea of low cost. with the idea of using "close to" it gives more people the ability to make this.

    Even though the drill is not rated for the voltage i gave it, or supposed to use that low amps, it has functioned fine, at no load it will spin just like normal, under load it is perhaps 10-25% slower than it was on the battery, i have used it for a week and the only bad thing to happen is the power supply box broke when it got hit by something so now it exposes all the circuitry.

    I hope you keep in mind that in theory this should not work properly at all, but theory and application do have some difference this will happen all the time, in almost any situation what you design on paper can very easily not work when you build it.

    Once again the truck engine was an easy way to explain what i was doing. I do suppose you are correct as far as Dc motors, when i said it would not be affected by reverse current i meant that it would still run, although backwards. when i define affected by the reverse i would say it does not work.

    I hope this addresses all you points, and thank you again for posting a comment i do value all of your input and will take it into consideration for my future instructables, which i hope you check out.

    -Transistor 2


    Reply 4 years ago on Step 7

    I suppose the old proverb applies here, about the honey bee which can't possibly fly because it's clearly too fat for its wings and yet it flies around anyway. I really didn't mean to sound patronising, and I agree that it's better to re-use something in any capacity rather than throw it away because it isn't perfect - Instructables has the very purpose of showing others how to make-do. If you have safely re-used your available resources and gained something useful out of it then you deserve our congratulations. I'm afraid that it's very common these days for online posts to be misunderstood or attacked violently for very little reason, usually by ignorant morons who have no business being part of a civilised community. Courtesy costs nothing and is worth much. Thanks for your contribution and keep up the recycling.


    4 years ago

    Pretty cool, of you wire a lot check out my diy, it would help:)


    4 years ago on Introduction

    Your problem is amperage not voltage. You cannot do this with a normal wall wort power adapter. you need a power adapter that has close to the same voltage but high enough amperage to power the device. For most 18 volt drills you're going to need at least 20 amps. I did this project a few years ago with an old Dewalt drill I used an 18 volt 350 watt power supply I had laying around and mounted it inside the small plastic tool box. I also added a small cooling fan inside the toolbox to keep the heat down. I found an almost identical power supply just now in I'm sure you can find one cheaper for you may have one laying around like I did. Just thought it would be a good example of what you do need to make this work.

    Also going over the voltage to the tools rated for his mistake. You can afford to go a few volts over or under in the motor will function just fine but when you start going double the voltage you're risking burning out the motor. There's no reason to increase the voltage you need to stay around what drill is rated for that's why I suggest with an 18 volt drill that you stick with 15 to 20 volt power supply. perferrably using and actual 18 volt power supply with the proper wattage so you have ample amperage to power the drill's motor.

    1 reply

    Reply 4 years ago on Introduction

    you are correct, the motor needs more amps than volts in this instance, yet due to the goal of making this for no extra cost i just used the best I had lying around, keep in mind as you reed this the project is supposed to be ultra cheap and easy using whatever you may have around the house, yes i would love to have a power supply like you mentioned but i didn't want to spend the money. but the drill still works after 3 days of use, so i would say it is a victory.


    4 years ago on Introduction

    it worked for me, you should try again with a bigger addaptor maybe 75% more than what the battery puts out volt wise

    2 replies

    Reply 4 years ago on Introduction

    1. Did you try to actually drill/drive a long screw into something?

    2. Are you sure that the difference between 24 and 12 is less than 75 %?

    3. The voltage rating of the adapter should be as close to that of the battery as possible, what really makes the difference is the internal resistance (Ri) of the power supply, i.e. how much current it can provide.

    Learn Ohm's law...


    Reply 4 years ago on Introduction


    1, i have not had enough time to screw something i have run the drill and it worked just like it was new i applied pressure to the end and it was fine.

    2 although you make a valid point i know 24 is not 75% more than 12 i just used it for a basic starting point to look for, ideally one would want to have the same power output from the converter as the battery, amps times volts. but because this is such a basic motor and stuff you can have some room for error in witch the device will still function ie. mine with 12 and 24 volts.

    3 yes i would want to match the battery at maximum levels and all, but i dont need to to still make it work, take a truck you can have a big truck with a little engine and it will run where as you can have a little car with big engine although there will be limits it is the same idea with the drill and power supply,

    4 the power supply was just fine it didnt explode or anything all it does is put out a certain supply, what would break is the drill motor if i had say 120 volts it would be too much, but this works, as for amps i can be a little low that is ok as long as i compensate by adding more volts

    5 although this isn't perfect it works and achieves my purpose very well, if you would like to do the math and find the optimal settings for everything be my guest i will add you in if your correct and give you credit,

    6 should you not believe me i will try to get a video up as soon as possible to show it in action and have it drill things,. until then i appreciate you insight and curiosity.


    4 years ago on Introduction

    This is BS. The DC adapter you have there puts out 600 mA at 24 V while the drill is rated for 12 V but 10-15 times the current, maybe even more. You'll fry this adapter as soon as you turn it on. You need an adapter that does at least 12 V at 10 A (120 W), like an old computer power supply (ATX), and appropriate wires that won't create a big voltage drop across them (at least 2.5 mm^2 or 13 AWG)...


    4 years ago on Introduction

    I have tried this... with such a small AC->DC converter this will not work. The current needed by the power tool is much more than the adapter can provide. These batteries used in the tools can provide quite a bit of current!