Machining funnel shaped counterbore in ductile iron

[Trukker]

For a 12 mm diameter hole in a ductile iron part, I need to machine a funnel shaped counterbore (inverted frustrum of a cone). The entry diamter is 24 to a depth of 3mm then there is 45 degree taper for further depth of 3 mm. As can be calculated, The outer diameter of the flat land is 24 - (2 x 3) = 18. The inner dia is the hole dia i.e. 12 mm.
The two fillets created have 0.5 mm radius.

Can you please give me some ideas on how I can have this machined on volume basis.

Thanks for your help !

 

[mrainey]

I'd look into having a custom form tool made, either solid carbide or using indexable carbide inserts.

indexable carbide insert type - this is a good company

http://www.vermontindexable.com/

solid carbide - research some of these

http://www.thomasnet.com/products/carbide-cutting-tools-10631455-1.html

Software For Metalworking

http://mrainey.freeservers.com

 

[eromlignod]

Are you saying that the cone is a 45 deg. one? Couldn't you just use an ordinary metric countersink bit?

Don
Kansas City