Toolpaths different when changing tool

[cunnc1]

Hi guys, new to Fusion and CAM in general and I've really hit a brick wall!

So the part I'm trying to make is a specifically sized washer, OD 51.5mm, ID 14mm.

I originally used MeshCAM V6 to cut the part but with just a circular toolpath in 316 SS I quickly burnt out my favourite HSS end mill.

I figured the reason was that with a curcular toolpath 50% of my endmill was always in contact with the SS.

So I thought it time to knuckle down and learn Fusion360.

I came up with this what I figured would be a perfect toolpath which I've attached below.

I then realised that I still had my old end mill selected.

So I made a new tool, same feedrate, plunge rate etc, just with the new dia.

When it rewrites the toolpath I get back to a circular toolpath which I just cannot for the life of me get back to the one screenshotted.

Any advice would be a MASSIVE help before I outsource these to be lasercut.

Many thanks, Craig

[jeff.walters]

Did you select the new tool in the operations? It would help a lot if you could post your file so we can see what you have set where.

[cunnc1]

Thanks for the reply Jeff.

http://a360.co/1S60Xhs

I hope that is the correct way to share things here.

When I realised I selected the wrong tool, I edited the dia of the selected tool to find it ruined my toolpath. So I undid that then created a new tool and even then I couldn't get my desired toolpath back.

Thanks, Craig

[jeff.walters]

So are you trying to cut this from sheet stock or disks?

[cunnc1]

It will be cut from sheet. So my thinking being a helical decent into the sheet, then circular motions to clear about 10mm of material around the washer to save burning up more pieces.
I couldn't find much info on milling sheet metal from my searches as I can only assume a lazy cutter would be the best tool for the job.