For accurate drilling, a drill press is a much better choice. While the drill press isn’t portable and is hard to use with large objects, anything which can be put onto its table and fit under the drill chuck, it provides much more control and accuracy versus a handheld drill. More than anything, a drill press provides a sure way of maintaining the drill bit perpendicular to the work piece.
While electric hand drills are the most common and oldest portable electric hand tool on the market, they still have limitations. When one needs accuracy, a hand drill isn’t the best way to go. Accuracy with a handheld drill is totally dependent upon the skill of the operator, being able to hold the drill steady and exactly perpendicular to the material being drilled. For most people, this is a problem. While some electric drills have built-in bubble levels to help, it still requires a fair amount of skill on the part of the operator.
Another advantage of drill presses over handheld drills is the speed on a drill press can be accurately controlled. Many drills offer variable speed trigger, allowing the user to use a fast or slow rotational speed as they want for the particular cutting operation they’re doing. However, there’s no accurate way of judging the speed the drill is moving at. On the other hand, all drill presses, from the least expensive up, have systems for accurately setting the rotational speed through a series of pulleys.
Hard materials, such as stainless steel, require a slow cutting speed. High speeds only cause excessive friction which heats up the drill bit and strips its temper. Low speeds allow the drill bit to work the material without creating excessive heat.
Drill presses also offer much more power than hand drills as it’s possible to find drill presses with up to 5 hp motors. While these are very expensive tools, the extra power is needed when large holes need to be drilled in extremely hard materials.
Finally, drill presses offer the ability to control depth of cut accurately. A gauge and depth control is attached to the side of the spindle, which can be used to either see how deep a cut has been done or set to stop the travel of the spindle when the hole is at the desired depth.
Drill presses can be fitted with a table vice to hold the workpiece which helps ensure accuracy and they can also be fitted with a X-Y table for simple machining projects. While this won't make a drill press into a machining mill, it will simulate one well enough to complete an AR-15 80 percent lower receiver. That's not the world's most accurate milling requirement but it's a whole lot more than you can do with any handheld power tool.
While drilling into wood with a hand drill isn’t difficult, metal is another story. In most cases, a drill press will provide a much easier and faster way to cut through the material, especially harder metals, such as steel or stainless steel. It’s highly recommended to use cutting oil when using a drill press to cut holes into metals. This reduces wear on the drill bit, providing for a longer drill life.
Selecting a Drill Press
There are several different things to look at, when trying to choose a drill press. First of all, you'll need to know the type of work that you are going to do with it. Most specifically, you need to have an idea of the types of materials you are going to use, the size of the workpieces and the size holes you'll need to bore through them.
Physical Limitations
Don't even bother looking at a drill press that won't accommodate the physical size of the pieces you want to drill. That means a combination of the distance between the chuck and the table, and the distance from the chuck to the column, or throat depth. Throat depth isn't always provided for drill presses so you may have to estimate it based upon the dimensions given. However, the distance between the chuck and table is the standard dimension by which drill presses are sized; in other words, a 13" drill press is 13" from the chuck to the table.
You will need to decide on whether you want a bench mount or floor mount drill press. This will be determined more than anything by the amount of vertical height you need between the drill chuck and the table. Floor mounted drill presses allow for larger workpieces.
Motor Size & Speed
Motor size is the most important factor for the size holes you can drill and what type of material you can drill them in. When you start working on metal or start drilling large holes, such as with hole saws, you will need a lot of power. Just to give you an idea, cutting a 1" hole through mild steel strap with a hole saw can bog down a 3/4 HP motor if you don't take it slow.
The motors will be connected to the spindle with a belt or belts. There is a series of pulleys, which allow for adjusting the spindle speed of the drill press and while all drill presses pretty much cover the same range of spindle speeds, the larger the drill press, the more adjustment steps it typically has. Lower speeds are needed for cutting harder materials to prevent the drill bit or cutting tool from overheating, losing its temper and getting dull.
Stroke Length
Another very important specification that most people don't pay much attention to is the stroke length. This is the distance that the spindle can travel downwards, from the resting place to its maximum depth of cut. A drill press with a short stroke length will limit what tasks you can use it for.
The Table
Tables on pretty much all drill presses are adequate with most of the smaller to mid-sized drill presses having round tables which tilt and turn. They will be slotted for mounting a drill press vice or for using hold-downs for your workpiece. The larger drill presses will have square tables, which are T-slotted for mounting to. This is more like a mill's table is designed, allowing the workpiece to be clamped to the table in a variety of ways.
Other Options to Consider
While the major specifications are really the deciding factor in buying a drill press, some manufacturers add on extras to their products, making them easier to work with.
Depth Gauge
One of the most useful extras to find is a depth gauge. These might be a rotary gage that goes around the stroke handle or a linear gage attached to the spindle. Either way, they allow you to know how deep you are drilling into the material.
The depth gauge will usually have some sort of a stop on it, allowing you to pre-set how deep you will drill and then stop. This prevents drilling all the way through the workpiece, a very useful feature when milling on a drill press.
Worklight
You might also find that a drill press comes with a light attached. These can either be on a gooseneck or mounted to the head behind the spindle and they're extremely useful for improving visibility of your workpiece.