Re: Winding a Spiral Primary

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Esondrmn@xxxxxxx 

I slide one of the inexpensive tubing benders on to the coil of 
tubing before I start.  These look like a hollow, tight coiled 
spring.  This comes in handy for working the inside few coils that 
need to be wound tighter than the original coil of tubing out of the 
box.  I tie down one spot then work the tubing into the approximate 
correct location for the whole next turn then tie the next spot, 
etc.  I use the shank of a drill bit of the correct diameter to 
continuously check and adjust the spacing between adjacent turns.

Ed Sonderman

In a message dated 11/26/2005 4:01:24 PM Pacific Standard Time, 
tesla@xxxxxxxxxx writes:
At 12:55 PM 11/26/2005, Tesla list wrote:
>Original poster: Drbillpmt@xxxxxxx
>Hi All,
>
>I'm having a problem winding spiral flat coils of 1/4" and 3/16"
>copper tubing. Som of the pictures posted show flat coils that are
>works of art! I'm usually pretty good at things mechanical, but I
>just can't seem to be able to devise a way to repetitively, and
>accurately, wind many coils necessary for a customer order.
>
>The center of the spiral is quite small.
>
>Dr. Bill

A few strategies spring to mind..

1) use some form of guides and carefully transfer the coils from the
box the precoiled tubing came in (the usual TC approach, but tough to
get really tight tubing

2) A spool with two flanges spaced by the thickness of the tubing and
then you wind under a fair amount of tension.  Might want to fill the
tube with sand or lead first to prevent crimping with small radius turns

3) A "three roller" kind of tubing bender where you carefully change
the ROC as you go.