Subject: Making a corkscrew coil?

From: [email-masked] (Laughing Larry)
Date: Sun, 28 Jan 1996 00:34:40 GMT

I need some info on how to design and make a corkscrew helix.
I am not talking about a simple coil of 1.5mm wire, but a proper
corkscrew shape, with a solid core and shaped spiral.
Is there some method of working out the cross section and how do
i go about machining such a thing?

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From: [email-masked](Dale A. Keltie )
Date: 27 Jan 1996 18:17:06 GMT

In <[email-masked]> [email-masked]
>i go about machining such a thing?

Larry - 

Would coarse screw threads, single-point cut using a taper attachment,
work for this?

Regards, Dale

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From: [email-masked]
Date: Sat, 27 Jan 1996 19:42:24 GMT

>i go about machining such a thing?

Such an item would be made by milling between centers.  The horozontal
feed is geared to the rotational feed of the centers.  So, as the mill
progresses horozontally, the part rotates to produce the helix.
Depending upon how deeply you cut with the mill, you can leave a
central shaft or just a spiral flute.  

This can be accomplished several ways.  If you are patient, you can do
it manually by making a set of setting tables that will allow you to
coordinate the X axis and rotational movements.  You wil generally get
some steps that must be blended out by hand.  

You could also set up the mill with a pulley and belt setup that will
drive the rotation of the part between centers at the horozontal
movement is advanced.  Depending on the size of the pulleys you
select, you can end up with a long or short spiral helix.  

All of the above methods are outdated with the advent of CNC, but for
a home shop machinist, the methods above will work.  

J. M. Stuart

Engineer / Inventor / Patentee

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From: [email-masked] (Edward Haas)
Date: 27 Jan 1996 12:08:40 -0800

--If you mean to wind a coil of material that is fairly thick, 
check out the article I wrote in a recent issue of Model Engineers 
Workshop (don't remember which issue). It talks about constructing a coil 
for a mass-driver, using "wire" measuring 1/8in. by 1/4in. cross-section, 
which was bent so that the 1/8in. sections were laying one atop the other 
in a one-layer coil. The trick is to feed the stuff through a channel 
that's clamped onto the toolpost of your lathe. This makes sure the wire 
doesn't deviate from its course on the way to the winding mandrel. The 
other trick is to turn the mandrel around with a hand-crank, due to the 
slow deposition rate of wire onto the coil.
-- 
	"Steamboat Ed" Haas	:	...Yet another
	phone: 	(805) 968-7534	:	crackpot...
	FAX:	(805) 562-8928  :	
		---Decks a-wash in a sea of words---

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From: [email-masked] (william thomas powers)
Date: 27 Jan 1996 15:14:27 -0500

>i go about machining such a thing?

I would forge it!  use a slightly undersize swage to create the
flanges and hot twist it to shape.

(I never understood why folk want to machine things that are much
easier forged.  A friend of mine took a gunsmithing course and
one of their assignments was to file out a flintlock lock. He
looked at the specs and forged it--faster and you get the advantages
of grain alignment--. They downchecked it because it was supposed to be
filed because "No one does forging anymore".....)
Thomas
Columbus, OH