If you are working with metal, then chances are that at some point not only will you need to drill through it, but you also may need to enlarge existing holes. You might need to do so to insert bigger bolts and nuts, to pass cables through, or for any other such purpose.
The point here is that you now need to enlarge an existing hole in metal, but you don’t know how.
Can You Enlarge a Hole in Metal?
The fact of the matter is that if you can drill into metal and cut it apart, then there is no good reason as to why you couldn’t enlarge an existing hole.
OK, so enlarging an existing hole in metal is harder than doing so with wood, mainly just because metal is of course a lot harder than wood, but with that being said there are still many good methods at your disposal for accomplishing this task.
Let’s move on and discuss all of the different methods for enlarging an existing hole in metal.
5 Ways to Enlarge an Existing Hole in Metal
If you are planning to enlarge an existing hole in metal, then there are five good methods at your disposal, so let’s take a quick look at each of them.
1. Metal File
If you can’t be bothered to use or buy any power tools then the best method at your disposal for enlarging an existing hole in wood is to use a long and thin metal file. Something that you do need to remember here is that holes are of course circular, so if you want to achieve that perfect circular shape, you will want to use a rod file.
In other words, you need to use a metal file that is circular in shape, not square, much like a piece of sharpening steel that you would use to sharpen knives. As long as you have a very tough, high-quality, coarse, and circular metal filing rod, then you should have no problems grinding away that extra material.
Yes, it will take a bit of muscle for you to accomplish this task, as well as a good bit of time, but it is doable, and thanks to the fact that this is a manual task, you have the ability to be very precise because things just don’t move very quickly, thus giving you plenty of time to think.
2. Specialized Sandpaper
The next option that you have at your disposal here is to use sandpaper. What you need to be aware of here is the fact that you cannot use normal or plain sandpaper for metal. In other words, you cannot use the same sandpaper that you would use to sand down wood as you would for metal.
Sandpaper designed for wood will not work on metal as it’s just not tough enough. What you need is a special kind of sandpaper known as silicon carbide sandpaper. All you really have to do here is to get your silicon carbide paper in hand and then get sanding.
If you don’t want to use your hands, or if for some reason you cannot get your hands into the hole, then what you can always do is to wrap a layer of silicon carbide sandpaper around a small wooden dowel. Doing this will allow you to insert the sandpaper-covered dowel into the hole to enlarge it. This also helps make life easier because it provides you with a good handle to hold onto.
3. Tapered Reamer
A tapered reamer is a very special tool that is specifically designed for this task. A tapered reamer kind of looks like a very thin and narrow ice cream cone, something that comes to a point at the front and features a wide handle at the end, complete with the tapered design.
This is a tool that is designed to enlarge holes in metal, as well as to remove burrs from metal holes that have already been drilled. If you just have a couple of holes that need to be enlarged, then this is a great method to go with because all you have to do is to hold the tapered reamer at the handle, insert the front end of it into the hole, and then apply a good bit of pressure, while twisting back and forth in order to enlarge the hole.
This is actually a very precise way of enlarging an existing hole in metal, because it is quite a slow process, and when you work slowly, it does allow for precision. That said, you do of course need a good bit of muscle for this task, as well as a tapered reamer too.
4. Jab Saw
For those of you who don’t know, a jab saw is also known as a keyhole saw or an alligator saw, and the defining feature of this tool is that it features double-sided teeth that make cuts on both the upstroke and the downstroke.
As you are probably aware, if you’re going to use a saw for metal, then you do need to have the right kind of blade. A good type of way to go with for this purpose is a carbide blade, but there are others too.
The blade of this saw is tapered, which is perfect for enlarging existing holes, especially when the current hole is very small. All you have to do is to insert the end of the blade into the existing hole, cut out to the edge of the new hole in which to cut, and then cut out the hole along its diameter. If you are looking to save time and you have a jab saw on hand or you are planning to invest in one anyway, then this is a fantastic option to consider.
5. Hole Saw
The other option that you have at your disposal here is to use a good old hole saw. Just remember that the hole needs to be fitted with a bit that is specially designed to drill through metal. Also remember that you will first need to make a wooden plug to fit into the guide section of the hole saw, as there is no existing metal for the pilot bit to grab onto.
Measure and cut a wooden plug that will fit into the guide of the hole saw bit. Of course, also make sure that the bit of the hole saw matches the diameter of the new hole that you wish to drill. Once you have the plug created, you can then simply drill out the new hole.
Whether you want to call this enlarging an existing hole or simply drilling a larger one over the smaller one, the result is the same.
Mistakes to Avoid, Tips & Tricks
Lastly, before letting you go, here are some extra tips on how to make the process smoother:
- Metal shavings can be extremely dangerous, so always wear the proper eye protection.
- Metal shavings and those burrs can also be very sharp, so we recommend wearing some very thick word gloves when drilling and working with metal.
- While the manual methods that we discussed today work just fine, they do require a whole lot of effort because, as you probably know, metal is very tough. So, any of the options that we discussed above that use power tools are probably the best ways to go.
Summary
OK, so now that you know what the five best methods for enlarging an existing hole in metal are, you can choose the one that works best for you.