How to widen hole with cup saw?

The theme of our article is a hole with a cup saw, but first, we have to ask, do you know what a cup saw is? What is the application of the cup saw and what types of cup saw exist? In addition to answering these questions, in this article, we will show you how to correctly use a cup saw and how to enlarge a hole with the cup saw, come on guys!

What is a cup saw?

It is a widely used tool among electricians! The cup saw can be found in various diameters and each model has specific technical characteristics for its application. The models vary according to the material your teeth were made of, there is a steel and diamond cup saw.

When buying a jigsaw, it is important to look at all these characteristics and see if it has all the teeth, if it is not burnt and when the model is diamond-shaped, check if the teeth have a light diamond layer.

How to use a cup saw?

To use the glass saw correctly, you need to follow some useful tips that we will present. First, you must know that you can use the saw to drill different materials such as wood and various metals, but for that, it is necessary to choose the appropriate saw.

In order not to reduce the service life of the saw, it is essential to operate with the recommended RPM for the specific diameter being used. In this table below you can find the ideal RPM for each diameter according to the material to be drilled.

Table saw RPM table

At the time of drilling, you must exert sufficient pressure to cut the material, avoiding sudden chip movements. Another important recommendation at the time of drilling is regarding the cooling of the saw, ie, if you do not follow these tips, it will certainly decrease the equipment’s life. Never use fluids to pierce molten steel because the chip comes out in a very small size, it can lock and with that, it will inevitably damage the saw.

If you want to use the power saw in a portable drill, you will need to use a drill bit as a guide. It is the most efficient way to guarantee the lock on the material you want to drill. It is important to inform that it cannot be any drill, it must be approximately at the height of the teeth of the saw.

How to widen the hole with cup saw?

Now we are going to show you how to widen a hole saw using another hole saw. For this we will need to use this OPA support from Starrett that is shown in the image below.

How to use the OPA cup saw holder?

If you don’t know it yet, this OPA support can make your life a lot easier when it comes to widening a cup saw hole, let’s see how it works! Note that in our example, a hole was made with a 32mm cup saw, as shown in the image below.

Example of drilling with 32mm Starrett cup saw

If you simply change the saw for a larger one, you will have a huge problem, since after the hole has already been drilled, you will not be able to increase it using just another saw because it no longer has the surface reference for the guide drill.

It is precisely in these situations that we need to use OPA support. Then just replace the guide drill with the OPA support that has two threads, that is, it is possible to fit two saws. Now just fit the larger cup saw and then fit the smaller cup saw, as shown in the image below.

With Starrett’s OPA support you can use two cup saws

With the two chainsaws already fitted to the Starrett OPA support, it is now possible to widen the hole because the smaller cup saw will serve as a guide for the larger cup saw as shown in the image below. Now just drill the new hole and that’s it, problem solved!

See that the smaller cup saw serves as a guide for the bigger cup saw!

If you still have doubts about choosing a body saw, we will indicate this video from the Mundo da Elétrica channel, where the types of cup saw and the recommendations for use for each one are shown, it is worth checking out!

As already said, it is very important to use the correct cup saw for the material to be cut, just as it is important to make the drilling with the proper rotation and always cooling the cup saw so as not to damage it. If you follow the tips we give you correctly, you will certainly do quality work!