[fjd]

Its been too long and i have forgot how to program in gibbs
a tapper bore.
What i have is a casting (steel) with 7 inch hole by 4.5 inch.
I am needing to bring the bore out to 9.5 inchs. iam wanting to
use a 6" face mill and cut depth of .115 inchs and redusing the
the diam by .005 on each pass.
I am just drawing a blank here.

[HuFlungDung]

Create a spiral helix. Subtract the diameter of the cutter from the diameters of the hole, top and bottom, to find the actual radii for whatever your "draw helix" function would call for. I don't have Gibbs, but this is how I would do it in OneCNC.

[fjd]

Thanks HuFlungDung
I find it in Gibbs milling i had to click on the wall angle.
was able to change the ange to get it to drop .0025 in the
ID per pass. i used .5 deg

Thanks again
fjd

[Gibbsgod]

You can do this 3 ways (more also but, these are the most common)

#1 If you have Solids, just select the faces of the taper hole and use a contour operation.

#2 Create a helical taper with the "Create Helix" Plug-in from the pulldown menu (plugins pulldown)

#3 Create a contour operation and change the wall angle to our desired taper. (The icon next to the tool depth settings in the contour process)

Good luck.

GG

[fjd]

I am a little slow at replying Gibbsgod #3 worked great
for what i need to do .Some time you can't see the
forest for the trees.

Thanks again