Re: [CAD_CAM_EDM_DRO] internal contouring with cnc

Hi Gerry:
The success you have will depend largely on the length to diameter ratio
of the bore.
CNC implies single point boring for this application.
You will need a long and skinny boring bar, and it will vibrate because it
is sticking out so far and cuts in an unbalanced manner.
If your bore has a variable diameter, you cannot get around this basic
principle and CNC will not help you overcome it.

As I see it, you have three choices:
You could split the bore up into shorter segments so you can use a stubbier
bar.
You can split the bore lengthwise into halves, mill your profile into each
half, and then glue it back together.
You can get better and faster at making reamers.

Each of these options implies different equipment and a different focus on
how you intend to get where you want to go.
I have no idea whether this kind of work is permissive with respect to
splitlines and their orientation, but once you've determined that, there are
lots of smart guys on this list who can help you tune the method that you
end up choosing.

Do some experiments to find out which of these basic methods has the most
promise and then get back to us.
Cheers

Marcus

----- Original Message -----
From: "caerbr" <somersgarry@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, August 09, 2002 4:48 PM
Subject: [CAD_CAM_EDM_DRO] internal contouring with cnc


> Hello - I am an amateur flutemaker, working in wood and delrin(a
> polymer), and I have been wondering about the possibilities which a
> CNC lathe might offer for creating the bore of the instruments. The
> bore profile of wooden flutes is rarely a simple cylinder, and varies
> from flute to flute, and is one of the most time consuming parts of
> the whole job. Small changes in bore profile also have a crucial
> effect on the qualities of a flute. The traditional method of making
> a flute is to take a wooden blank of the correct size, drill a pilot
> hole and then use a specially constructed reamer in the lathe to get
> the final internal profile of the bore. Problem is - you have to make
> a new reamer every time you want to modify the bore profile - which
> makes prototyping a very slow business. So I have been wondering if
> there is some technique available(not too expensive!) using a CNC
> setup and a controlled adjustable boring tool which I could program
> to cut a given bore profile, which I could then easily when I wanted.
> This would eliminate the time and effort involved in making new
> reamers every time I want to experiment with a new bore contour. So
> there it is - any help or suggestions would be much appreciated.
> Thanks in advance.
> gerry