What is meant by "backed off" or "backing off" cutters?

[HMF]

Hey Guys.

Another dumb question from dumb Nelson,

What is meant by "backed off" or "backing off" cutters with respect to a milling cutter, and what is the purpose of it?

Thanks!!


Nelson

 

[HMF]

It has something to do with relieving the angle behind the cutting edge so that it does not rub. Rather like front rake on a lathe tool.

That was the explanation I saw elsewhere, and frankly, it makes no sense to me, so I was hoping one of you guys could explain it better.

Thanks,

Nelson

 

[bcall2043]

Re: What is meant by

The term "backing off" or "relieving" is used for some types of milling form cutters such as an involute gear cutter. If I have done it correctly the attachment is the US Patent #817885 showing how such a form cutter can be relieved or backed off in a lathe.

Regards, Benny
In middle Tennessee USA

 

[Hawkeye]

Re: What is meant by

I was wondering the same thing last week. Here's one of the videos I found.

[video=youtube;PTZBSlNyKi4] http://www.youtube.com/watch?v=PTZBSlNyKi4 [/video]

Watch the tool holder as it starts each cutting tooth at full height and takes a bit off on a slope toward the back of the tooth. As has been said, it stops the trailing part of each tooth from rubbing on the work.