What is a metal hole drill?

Isn't every drill a hole cutter? We're almost reaching philosophical levels here on the BAER blog. The answer is: well, sort of – but no. A hole cutter for metal or plastic is a tool that has very little in common with the familiar twist drill bit.

Things become somewhat clearer if we look at what else the hole cutter is called. The correct term is actually hole saw – the name describes what happens when the tool is used much more clearly.

Why do you still come across references to a hole cutter from time to time, how exactly does this tool work and can it also be used for thread machining? We asked ourselves the same question, and you can read what we found out in this blog post.

By the way, there's no doubt about where you can find high-quality tools on the subject of thread production. Why not visit the BAER online shop!

Saw or drill – How the confusion arises

We encounter these cases frequently in this blog too: in everyday language, terms are established that don't actually match the actual product designation. The phenomenon exists among DIY enthusiasts just as much as in professional circles, and as long as everyone knows what is meant, it's not a problem. To prevent ideas from drifting too far apart, it's advisable to remind ourselves from time to time what things are really called.

Admittedly, the hole saw doesn't make it entirely easy either. With its hard metal teeth, it is strongly reminiscent of a saw on the one hand, but the circular shape, the use in drilling machines and the fact that a centre drill is an integral part of the assembly speak very much for the designation drill.

However, in this case at least, appearance isn't what matters, but rather the process, and here the situation is crystal clear: the hole saw does not saw and drill. So keep that in mind the next time someone mentions a hole drill. But enough about terminology, back to the topic.

Perfect for large diameters: How does the bi-metal hole saw work?

Hole saws are used primarily when the goal is to create round openings with a large diameter in thin workpieces. The maximum thickness is limited by the height of the hole saw (i.e. the cutting depth). Since, unlike actual drilling, only a small amount of material is removed here, it is also not possible to create blind holes this way, as the drilling core remains and would have to be removed laboriously.

Classic applications are therefore primarily sheets and metal plates made of steel, stainless steel, wood, plastic or plasterboard, through which pipes are to be routed or into which socket outlets or device boxes are to be inserted. This is where the hole saw can demonstrate its strengths. It can be used in pillar drills, hand drills and even in cordless drills, provided the torque is sufficient.

Various saw blades can be inserted into the arbour of a hole saw, allowing you to produce a range of diameters with the same tool (e.g. 32 mm, 40 mm, 60 mm or 68 mm). In the professional sector, hole saws are also used where the arbour plate and saw blade are permanently connected to each other. In these cases, you need a separate tool for each diameter.

In the centre of the chuck sits the associated centre drill, which hits the material first, carries the saw blade with it and ensures that the hole is perfectly circular in the end. Incidentally, it actually drills and doesn't saw.

Can a hole saw create a core hole diameter for thread cutting?

In theory this is conceivable, but in practice it is almost impossible to implement. The idea already fails on a few simple prerequisites. Hole saws do produce perfectly circular holes at first glance, but they are not primarily designed for precision and they also leave a relatively rough surface. Precision and surface finish are, however, two central criteria that are decisive for the quality of your thread drilling core hole diameter.

Regardless, you will not easily find a hole saw with the appropriate dimensions for your thread. You have little room for manoeuvre here, as the specifications are strict when it comes to the diameter of the core hole – otherwise the tool will break quickly during work or become jammed.

And finally, the maximum material thickness will also be a limiting factor, because at this point the application range of the hole saw is very restricted and overlaps only very little with components in which threads are typically cut. It is therefore always a good idea to fall back on classic core drill bits.

What do I do if I need a hole with a large diameter when thread cutting?

If the hole saw can only provide limited help with thread cutting, then you naturally need an alternative as soon as you are dealing with large diameters. In industry, where sectors such as mining or shipping sometimes require really enormous thread sizes, core drills or mills in CNC machines are used. For everyday work or threads in your next DIY project, you are well served with the larger sizes in the range of twist drill bits.

In the BAER online shop you will find twist drill bits made from high-performance high-speed steel in many designs for drilling holes of up to 30 mm diameter (also available with reduced shank featuring a 13 mm shank diameter). With these, you can quickly create a core hole diameter of the correct size and with high surface quality, into which you can then cut your precise threads.

In addition to twist drill bits, our shop also offers you an extensive range with all the tools you need for thread machining, plus plenty of helpful accessories. Fair prices and rapid shipping are standard with us. Convince yourself! If you have any questions, our competent customer service is always at your disposal.