[NiCu2829]

I've attached the blueprint of the part to be made, photos of the actual part, the drawing of the carbide tool (it’s custom) and actual photos of the tool that I'll use to cut the feature in question.
I'm making this part on a Citizen L32 (Swiss machine). This operation is taking place on the main spindle, in guide bushing mode. The tool is running in an ER20 live tool. The material is 4140.
The tool is 1.000” diameter (.500” radius) and the blueprint calls for a .500” radius so initially I tried plunging the tool to depth. The photos of the part show the results of this, it chattered. I’ve just discovered the tool doesn’t have the proper relief behind the cutting edge (see photo) and is rubbing, causing a heavy burr and excessive tool pressure, which I’d say is contributing to the chatter.
Considering cycle time, I thought plunging would be the preferred method, agreed? Now I’m beginning to think that I should try and interpolate this feature, any thoughts?
Any help/insight will be greatly appreciated!

[deadlykitten]

hy nicu, the reason why some teeth do not have a relief, may be because that is a wild tool

such tools have consecutive teeth with relief on alternative sides; in other words, look for relief on the 'other side'

half of all teeth are for cutting up, while the other half are for cutting down

if you are not certain about that tool, and it's geometry, etc, try to take it to a local tool grinding shop, and talk with the guys & girls from there / just saying, they should have the experience to analize it and maybe regrind it


about plunging, hmm, better try to interpolate; if you interpolate, you may also use a smaller tool, and this means that cutting will be smoother, less vibrations, etc

the drawing of the carbide tool (it’s custom)

maybe you can replace your custom tool with :
... normal end mill +
... mini indexable T mill, from iscar : https://www.iscar.com/eCatalog/Famil...pp=63&GFSTYP=M

or use upper combo for roughing, and finish with your custom tool, so to make that custom tool last longer / kindly