Tim Wescott wrote:

John Flanagan wrote:

On Mon, 15 Aug 2005 20:24:27 +0200,
(=?ISO-8859-1?Q?Nick_M=FCller?=) wrote:


John Flanagan wrote:


I've got a part I need to machine (repeatedly) and was wondering if
anyone might make a suggestion for an effective and inexpensive
method. A photo of the cut that needs to be made can be found he


Does the part really have to look that way? I would say that the
designer has only seen a shop from the outside.



Ow, that hurts :^). But yes, it does. The part rotates in a sleeve.
The 90° cutout allows the part to rotate but it's rotation is limited
by a pin placed in the sleeve.

I've made these before just by chucking it in a fixed 5C holder on the
mill and by unchucking, rotating a little and then rechucking. Time
consuming PITRE plus it makes an ugly faceted surface. I was looking
for some method that would be faster and give a nice smooth surface
where the cutout meets the cylinder.


John

Please note that my return address is wrong due to the amount of junk
email I get.
So please respond to this message through the newsgroup.


If the pin is round then the edges of the cut don't have to be square,
right? I've seen a method where you mill on the end of a piece while
rotating it a controlled amount -- that sounds bad, let's try again:

* Use a milling cutter the same size or a bit smaller than your pin.

* Chuck the piece up in something that'll let it rotate, on an axis
parallel to the round axis of the piece and your milling cutter.
* Have stops that'll keep you from going to far in either direction.
* Use a _long_ handle (since you don't want to use a rotary table).

* Advance the piece into the mill, so the flange has a square side and a
round bottom -- ooh pictures would be nice here, wouldn't they?

* Rotate the part through to the other stop. Having the mill climb will
keep you out of danger (why don't you want a rotary table?).

* Back the piece out of the mill, for another square side.

Somewhere on http://staff.dstc.edu.au/chernich/ron/index.html there's a
discussion of how to make nice round ends on model engine connecting
rods this way.

http://staff.dstc.edu.au/chernich/ron/index.html, look at picture 41 and
it's caption.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com