Especially when taking stuff apart, you often come across screws that you just don't have the right driver for at hand. You could always borrow/buy/order a proper tool somewhere, but that takes time and possibly money. When those two are not available in sufficient quantities (or you're just impatient/bored/like to make stuff), then you might consider crafting the necessary tool yourself. In this Instructable, I demonstrate how to make a #6 Torx and a 1.3mm Allen key from wire, using just a triangular file.
Step 1: The Set-Up
The need first arose when a friend called me up late one evening in dire need of a 5 point Torx screwdriver. He'd had a bit of a beverage related incident with his Macbook Pro (Unibody, aka no removable parts). To prevent further damage, he wanted to unplug the battery and remove the mainboard to check for spillage there. Now you can easily remove the back plate of the Macbook with a Phillips driver, everything inside is held in place by the battery, which in turn is fastened by the aforementioned odd-toed Torx. Now I didn't have such a tool either, but still grabbed some tools and went over there to A) try kludging it, B) gloat about him having purchased this utterly unservicable machine, and C) hold his hand if anything goes wrong.
Now I had thought the easiest would be to just make a fitting flat-head driver and try that, but it didn't work. In the end it was quickest to just make a complete 5-wing Torx.
I didn't take pictures back then, and the original remained with my friend, so I wanted to see if that was just dumb luck, or if the result could be recreated. I got some gadgets from a Flea market today, among which an Ipaq with dead battery, and a bluetooth gps dongle. These have some screws which are slightly smaller than the smallest bits I've got in my toolbox, so I gave it a try. So
(BTW, the camera is from the same flea market, so I'm trying that out at the same time... Excuse the image quality.)
Step 2: Ingredients
-A File: A triangular, fine metal file should do the trick
-Wire: I used a clothes hanger because I happened to have it, but it proved to be a good compromise in strength while still being able to file it. Copper is too soft, piano wire is not easily filed.
-Pliers: Give you a better grip. If you have plier-like hands, you might skip these. Freak.
Step 3: The Blank
Cut off a straight piece of wire, and file the ends plane. For filing on the sides I like to grip the wire as shown in the second image. The pliers can accommodate a bit of wire, and you don't want the tip to stick out too much, so use a reasonable length.
Step 4: Start Filing the Faces
Chances are, that the wire is has more diameter than desired. I've found that filing all around is tedious and makes the rest just more difficult. So I start by filing a flat face into the side, and then another just opposite of it.
If you're confident, and actually bothered to measure, you could already make this the final thickness between two faces. I eyeballed it and rather left a bit more flesh, then to end up too thin.
Next I file perpendicular to the first to faces, to make a rectangle. These temporary faces contain the edges of the remaining faces. Again, one could measure the distance between two corners to determine the distance between these faces. Again, I eyeballed.
To make the edges visible in the following step, I color the small faces with permanent marker.
Step 5: File Remaining Faces
The remaining faces are done by filing at an angle from the middle of the small face into the large face. The marker helps as a reference to find the center.
If all went well, this should result in a Hex key of sorts. I go around all the sides until they are even, and hope that it is still thick enough, when they are. If you're making an Allen key, file down all sides until it fits the screws.
In the next step, we'll start from this to make a Torx. For this the Hex shape can still be left a bit too large.
Step 6: File the Torx
What's left is to file the notches. For this I hold the wire between my fingers, so that I can easily align the file and not slip. Try to keep the notches centered on the faces, and just get each one started. Then deepen them all around.
Getting it to fit the screws takes a bit of patience. At least Torx have some redundancy, if some of the wings are less pronounced, it will probably still work.
Step 7: Results
I think the outcome is quite acceptable. I actually completed the Torx before starting the Allen key, so I did some things different then shown here. That caused it take a bit longer, maybe 45-50 minutes including taking pictures and other stuff. After that I started the Allen key, and when it was done, it wouldn't grip the screws at all. I almost gave up on it, but ended up successful after filing a bit off the end. It's probably a good idea to make the hexagonal section tapered, so that you can vary the thickness a bit.
All in all, the Torx is probably more suited to this method. Even though it appears more difficult, it is actually more forgiving in performance, once it fits. For the Allen key, the margin between fitting in, and slipping is very small. The soft metal used here also makes it easy to over-tighten the screws, damaging the screw driver. If that happens you have to file the damaged area away... An upside to this is that it is nearly impossible to damage the screws themselves. A big plus when trying to remove recessed screws.
Below you can see that the screwdrivers fit well enough for the screws to stick, just from the friction.
This completes my first instructable, I hope it will be of some use.