How to square a round hole with files?

29th February 2020


	How to square a round hole with files


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			If you have a round hole cut into a piece of metal that needs to be turned into a square slot, you can do it using files.

			Preparing your workpiece
			First of all, you will need to apply a layer of layout ink around the general area where your hole has been cut.

			Using a straight edge and a scribe, you will need to carefully mark out a perfect square. Each edge should touch the circle.

			Clamp your workpiece securely in a vice with the marked surface pointing towards you. Don’t forget your filing block!

			Reshaping the slot
			For this task, you’ll need a three square file, a square file and a pillar file.

			You’ll be working on one corner at a time.

			Step 1 – Cut notch The first job is to cut a notch that will give you a platform for rapid material removal. For this you will need a three square file.

			The acute angle at the edge of the three square file allows you to cut into the edge of the circle without having to worry about your file cutting into the material anywhere else.

			This is why a square file is not used for this part of the process, as there would be more corners on your tool that you would have to worry about.

			Step 2 – Remove metal You can now switch to a square file and file away the metal until it’s close to the lines you have marked out.

			Step 3 – Finish Using a pillar file, you can now file right down to your lines.

			The safe edges on the pillar file mean that you can file right up to the corner without worrying about accidentally cutting into a second surface.

			Step 4 – Repeat Once your first corner has been filed square, rotate your workpiece and begin working on the second, then the third and the fourth.