Center indicator

My fifth-grade grandson recently came to me with a request: he needed to come up with a project for 3D printing, the kids from the internet would download toy soldiers, but he wanted to make something useful – could I help?

A tin can caught my eye.

– Try to find the center of a circular part.

– Well, I know that: we draw a diameter line, then make two marks with a compass, connect the intersection points – we get the center.

– That’s right, but in the workshop it’s more convenient and faster to use a special tool – a center finder. I suggest making that as a competition entry.

The device design is extremely simple – look at the drawing – it’s two side rulers fixed at a right angle, between which at 45° there is a third ruler positioned flat. We apply the side stops to the part and make a mark, then rotate the device at an arbitrary angle and mark a second line – their intersection will be the desired center.

The device can be made by printing it on a 3D printer, or the old-fashioned way – from plywood, plastic or metal plates joined with glue or welding. It’s only important to maintain the angles accurately.

…A week later, my happy grandson brought me a working sample of a self-made center finder as a gift, along with a diploma for winning the modeling competition. I don’t even know what to be happier about!

«Modelist-Konstruktor» No. 4’2025, Alexander ZHAROV