machineing radius edges

[charlieuk]

Im after a few ideas as its come up recently on another project that zeeflyboy very kindly helped me with but now its come up again.

I am trying to make this part not necessarily all on a cnc but however possible and that will be the easiest and cheapest way for a bit of a test.

basically the bit im stuck on is I want to put a 8mm radius on the edges of a bit of 25mm aluminum stock.

im not sure if my current cnc is going to be up for cutting ali but I could give it a try I guess.


What are my best options/methods?

many thanks

[magicniner]

If you want 8mm radii and that sharp step in size as in the image you can only do this as a 4 Axis milling job, CNC or Manual.

[m_c]

Radius cutter, however 8mm may be a bit big for anything but a reasonable size machine with a relatively slow spindle.
I've just checked the first cutter I found (arc euro trade), and an 8mm radius cutter is 24mm OD, with 8mm centre, and a 16mm shank, so a failry substantial machine would be needed.

Removing the bulk of material using a normal endmill and several passes would mean minimal cutting for a final finishing cutting pass.

Other option would depend on how good a radius you want. You could probably get a reasonably OK finish using a ball end mill and multiple passes.

[magicniner]

But how do you transition from one size to the other with a radius cutter?
I suppose you could clean the transition up with a file?

[m_c]

But how do you transition from one size to the other with a radius cutter?
I suppose you could clean the transition up with a file?

He only asked about the radius edges, not the stepped bit ;-)

It all depends on the quality of finish required.

[magicniner]

[charlieuk]

cool wasn't aware you could get something like that for metal, I was searching for round over bits but only found wood type ones. I may be able to put that in my x2 mini mill just. I can get away with not having the step for the prototype . I guess the best way to get that would be on a 4 axis machine, if anyone thinks they can cnc this if its not going to cost a fortune just drop me a pm

many thanks