[modeleng] Re: Spinning
- From: "Jesse Livingston" <fernj1@xxxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Wed, 9 Aug 2006 06:11:07 -0500
Spinning tools I have seen being used were at commercial spinning
establishments and were almost as long as an American baseball bat. The
long heavy handle gave plenty of leverage against the lever support pivot
pin which was in a horizontal bar with numerous holes along its length so
the leverage point could be moved as work progressed. What little spinning
I have done on my 12 inch Atlas lathe has involved putting a tool holder in
a "lantern style" toolpost and using the set screw on the holder as my
leverage point. However you do it, the lever point must be kept very close
to the work. You start spinning way down at the bottom of the circle of
sheet metal, right up against the smallest diameter and work your way
outward in stages. Be aware that the metal thins as you do this and you
must at times press the tool back toward the centre to keep from thinning
the metal too much. Oh, a cup shaped live tailstock must be kept tightly
pressed against the disc to hold it and force it to turn.
I watched a professional spin a 10 inch disc of 18 Ga. alumimium to form a
decorative shade for a flood light and it took him remarkably a short time
to make the thing. He was demonstrating it to me at the time and so took
longer I am sure. In the case of the aluminum, he did not remove it from
the lathe until it was finished, but then, aluminium does not work harden
like copper or brass. He spun the sheet against the metal form (production
shop ya know) and forced the metal both ways to prevent the aforementioned
thinning.
If all of this sounds complicated, it is until you have seen the process
actually being done. Instead may I humbly suggest that you draw two circles
on a piece of flat material. The smaller one about the size of the chimney
bottom and the other one at a bit larger than the bottom of the petticoat
pipe and the distance between them the length of the petticoat pipe. Now
cut out the piece of metal and remove a pie slice shape from one side and
then simply form the piece into a truncated cone??? That is how I have made
mine as well as the diamond stack funnel for my Falk #1. :)
Unka Jesse in Tenneesse
MODEL ENGINEERING DISCUSSION LIST.
To UNSUBSCRIBE from this list, send a blank email to,
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.
Other related posts: