Here is a step by step tutorial of how to make your own cutters.
First take a length of gauge plate or sometimes called ground stock, do not attempt making it from mild or stainless steel because ordinary mild steel does’nt contain the correct mixtures that aid hardening, like tool steel has.
Here I’m using 15.00×5.00mm gauge plate, drilled a 8.00mm hole in one end leaving 6.00mm of stock at the top side of the hole.
Round over the top of your bar.
Now using a hacksaw or dremel cutting disk, cut down at an angle from the top centre of the bar so that the cut lines up with the indide edge of the hole you drilled at the start.
Leave a gap at the top of around 5.00mm between the two angled cuts.
Next using a saw file, file the vee into one side until you have the two clearing ears, be careful not to file into the opposite edge, leave slightly flat tops to the ears so you can hone them up later.
Your cutter done it is now ready for hardening and tempering.