At the other end of the scale, my favorite shop, Tool King, which I mentioned in my previous article, had the set of tiny drill bits shown below:
These are just what every DIY PCB maker needs -- 10 each of various sizes from 0.4 to 3.2mm. In the image above I have shown them with a Pin Vise -- a small holder for small drills or other tools that is very useful for cleaning up holes or enlarging them to fit a large component wire. (This was not included in the set.) You can drill holes in PCBs by hand with one of these, but there are better ways to do it, like the small drill and press shown below, which I purchased years ago from a Tandy in Paris.
This is not particularly high quality, and the drill tends to wander if you are not careful, but it is adequate and very useful for the small amount of PCB work that I do. It comes with three collets (jaws) for the chuck that let it use drill bits up to about 2mm. You can also remove the drill to use it hand-held. It runs off 12V, but I usually put it on my variable power supply so it does not run so fast, because the stated 15,000 RPM off-load is too high for most drill bits. One day I will make a proper speed control for it …
If you want a high-quality small drill, you cannot pass up those made by Dremel. Apart from a range of tools (not just drills, they do so much more), they also offer a seemingly endless array of drill bits, grinding bits, burrs, saws, polishers, and other accessories, along with various mounts for use with them. I have the one shown in the image below that I acquired many years ago, and which has had a lot of use. As per the label, it was made in the US, but I don't know if they still are (their website does not have much info on that).
The manual (which I still have) says that the speed is around 30,000 RPM. This is really too fast for drilling, so a speed control is a good thing to have if you use if it for this purpose. For use with a grindstone as shown, 30,000 RPM is great. The last time I used mine, it sounded labored and got quite hot, so I think the lubricants may have dried up and it needs a service. As I have been in the throw-away society of Australia for 12 years now, I am thinking about buying a new one instead. (Note to self: don't be such a sheep, Australia has enough of them [LOL]. I might write to Dremel and ask for an opinion.)
If you have to drill different sized holes in sheet metal -- as I often do -- then please allow me introduce you to stepped drill bits as shown below. I really cannot recommend these too highly.
On the right we see a set -- 3/8", 1/2", and 3/4" -- on their holder, with a larger 6-36 mm bit on the left. I bought two of these for my workmate and me when he was looking for something to drill a hole for 32mm Conduit. After looking all over town and getting quoted over $100 to order one, I found these at an auto parts store for $14.95 -- how good value is that!
I regularly need to make holes for antennas, cables, etc., so I use these all the time -- they are soooo handy. They give a reasonably clean and smooth-edged hole and -- if you can get to both sides of the hole -- you can clean any "flash" off the back edge by just putting the drill into the hole from the other side. When you have to make a hole up to a bit over an inch, and don't have a drill bit, a stepped bit like this will save you having to look for a … well, let's move on to the next picture …
There is more than one way to skin a cat, as they say. Similarly, there is more than one way to make a hole. For neat, clean, precision holes in sheet metal, you cannot neglect a chassis punch. These work by starting from a pilot hole, through which runs a bolt that draws a cutter and a receptacle together.
They usually come in single sizes and need a spanner or an Allen key to use. I obtained this set when I was about 17 years old and I still have it. It is unusual in that the cutter of one size forms the receptacle for the next size down. This set has three sizes in all, and it also has a T-bar so you don't need a spanner or an Allen key. Chassis punches are not as convenient as stepped drill bits, but they do make a really nice neat hole, and are available in larger diameters -- up to 2" or more -- for things like meters and larger connection sockets. You used to be able to get them in unusual shapes for things like D-connectors as used on serial and parallel PC ports as well, but regrettably I don't have any of those …
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