Re: lathe arcs

If it's a one-off thing hit the grinding wheel and make a form tool.

Can you do multiple plunge cuts to create segmented arc? tool radius
and angles might give you a smoothe enough finish to get the job
done. If you're feeeding 0.005" per revolution, then a 0.005"
seperation between plunges would give the same finish.

Slow and tedious but sometimes ya just need to get the job done.

Dave





--- In CAD_CAM_EDM_DRO@..., "Carey L. Culpepper"
<mr.c@b...> wrote:

> I am in need of some help. I am doing lathe work on my cnc converted
> Hardinge hlv-h lathe. I am making forming rollers for specialized

sheet

> metal shapes. The first sets of rollers were strictly angular flats

and

> angles. The next stages require arcs (fillets). I cannot get my

machine

> to cut the arcs. It machines all of the flats and angles perfectly

but

> does weird things when it gets to the arcs. The drawings and gcodes

are

> Vector 8.2 generated. I even went back and altered a previous BobCad
> drawing(which was used to make the previous rollers without problem)
> with some fillets. Same type of problem. I have been working on

this for

> several long frustrating days. I have talked with Fred and tried

some

> things and emailed Doug and tried doing it with relative coordinates
> which did result in some arcs but still not accurate to the

drawing. I

> am using CNCPro as a control program. I have tried drawing in

different

> quadrants, all manner of different things- all wrong. This is

probably

> something really simple as far as setup(to the experienced

operator) but

> I just haven't found it yet. I made up a pen holder to draw the tool
> path on the lathe and have gotten some rather unusual shapes. Fred

and

> Doug have been very helpful but it is the weekend and I am

desperate.