I bought this radius end mill from Arc Euro Trade.
The shank is 12mm diameter, the radius is 3mm. Which when I purchased this as a one-off I thought would be the most useful size.
Why do you need this when you can create the same with a file and some patience?
Well, this allows you to very rapidly create a very good result that would take you ages with a file.
I used this end mill to create the radius edges on this part for my beam engine.
I must admit that the blending of the radius does not look perfect, but that is down to accuracy of the part to the tool in all 3 axes.
That is the only difficult thing about using this tool that takes time is aligning it with the edges and then gradually making small cuts and moving the tool in in x or y to increase the cut.
The results are great. As stated earlier the only difficulty is aligning the edges and this does take time.
As you can see from the piece above the corners that you get look fantastic.
Radiused connecting rods, the formal way is to use a rotary table and an end mill. If you don’t have a rotary table you can make hardened filing buttons and use these to file a radius on the end of the rod.
However, another way is to use an axle and a fixed height milling bit.