interpolating a tapered hole

[dry run]

Thanks for all the looks at my julian date engraving question. I still have no solution. Todays problem is this: I need to do helical interpolation on a tapered hole. Actually I want to make a straight hole tapered by interpolation. On my Mazak HCN 6000 (running in EIA--0M Fanuc clone) I can do helical interp. easily with g2.1 or g3.1 (using a P value for z move per full circle), But I need to make diameter decrease by an 8:1 ratio (1/8" per 1"). I'm relatively new to parametric programming, but there must be a fairly easy solution. (custom macro b) Thanks for looking....any opinions would be appreciated.

[christinandavid]

Take a look at samu's post #14

http://www.cnczone.com/forums/fanuc/...3_fanuc-2.html

Bear in mind this method will not produce a perfect spiral, but I used the technique along with a Z feed to successfully rough out an insanely deep bore with a feedmill by creating a very slow taper.

Other options are 'involute' interpolation - if you have it...

I wrote a custom b macro that can do this kind of thing in linear increments. I have the luxury of a pretty decent look-ahead speed, but the 'resolution' can be adjusted to optimise the feedrate. Give us a shout if you want to try it...

DP

[dpuch]

Anyone interested also take a look at http://www.cnczone.com/forums/parame...engraving.html starting at post #10