To cut perfectly even circles from sheet material of various diameters, you can make a milling compass. It allows you to do this as quickly and efficiently as possible at home using ordinary power tools. This is a simple device that will take no more than 1 hour to make.
Materials:
- Steel strip 20 mm;
- 1/2 inch pipe;
- thin tube 10-12 mm;
- broken metal crown.
Compass manufacturing process
A piece of strip is taken as the basis of the compass. Its length should be slightly greater than the required maximum radius of the circles to be cut later.
In the strip you need to make a longitudinal cut 6-7 mm wide. Holes are simply drilled at its extreme points, between which a groove is cut with a grinder in 2 passes.
On one side, the end of the workpiece is ground inward, and on the other, its corners are ground. A handle needs to be welded to the resulting workpiece.
On the groove side, a piece of half-inch pipe 50 mm long is welded. Then a thin tube 30 mm long is welded onto the strip itself in front of the cutout. Between them we make a handle, also from a thin pipe.
Now you need to weld the guide bushing into the half-inch tube of the compass. A part from a broken metal crown can be used as it. From the latter you will also need to cut off and set aside the part with the screw for clamping the centering drill.
Next we need to make the axis of rotation of the compass. To do this, you need to weld a piece of the same thread onto the head of the M6 bolt. This part will be inserted into a groove in the compass and clamped with a wing nut. The device is now ready and can be painted.
To make a large hole in sheet material or cut out a disk, you must first drill into the workpiece with a 6 mm drill. The compass axis is inserted into it.
Now we take a regular drill, put a stop on it, made from the top of the crown, and clamp it into a drill or screwdriver. After this, we cut with a drill in a circle through the compass bushing like a milling cutter.
