Bit Size Understanding

#1

I have a file that calls for a tapered ball nose bit and it’s listed in the program as Shank Dia .25
Side Angle 3.5
Tip Radius (R) .0313
My smallest tapered ball (SpeTool) is listed as R0.25 1 1/4" D1/4"
I measured the tip of this tool and it looks like it’s .0175

Is there an easy way to convert the Marking on the package of R0.25 by dividing it by 1/8 lets say for example and have that what I need to enter into the tip radius. .25 / .125 = .03125 pretty close to what the original file called for. Thanks

#2

I believe that is just a 1/16" TBN Endmill with a 1/4’ Shank, since it says Radius… Similar to this example from Amana

Amana Tool 46281 CNC 2D and 3D Carving 3.6 Deg Tapered Angle Ball Nose x 1/16 D x 1/32 R x 1-1/2 CH x 1/4 SHK x 3 Inch Long x 3 Flute SC ZrN Coated Upcut Router Bit

#3

Thank you very much.

#4

One more question, where do you get the 1/16" measurement from.on a unmarked 3" long 1 1/2" total tapered bit. All my bits are 3" with 1 1/2" tapered. And are marked R0.25 R0.50 etc

#5

Usually, there is just a part number and you will need to know the manufacture and then just look it up on their website. You will find that you have your favorites bits and will have them memorized like kids, not that you have a favorite kid, but you know everything about them once you have them for a while.