I did a little digging..."music wire" as supplied by McMaster Carr is AISI
1080 steel ASTM A 228 wire spec...wow...strong stuff. I was running with
the AISI 1080 formed properties for a quick reference manual. Here's a
link to wire properties:
_
http://www.matweb.com/search/datasheet.aspx?matguid=4bcaab41d4eb43b3824d9de
31c2c6849&ckck=1_
(
http://www.matweb.com/search/datasheet.aspx?matguid=4bcaab41d4eb43b3824d9de31c2c6849&ckck=1)
Yield is about 231-399ksi ! Sort of changes the game plan from when I
said 60-80 ksi yield...sorry about that.
In any event, one could pull to breaking on a sample and then mike it along
the way of progressive pulls...sort of like rubber testing? Then pick the
thick sections(?)
Rick Pangell
Editor of "The Max-Out" Newsletter of
The Magnificent Mountain Men FF Club of Colorado
In a message dated 7/28/2011 8:12:51 A.M. Mountain Daylight Time,
leop_at_lyradev.com writes:
Tapio,
The 20 pounds of force, using a 10kg hanging mass, does not provide the
stress necessary to get to the yield point of 0.35mm (about 0.0137") music
wire. The wire will not straigten with that force. The average breaking
point of 0.013" music wire is just over 50 pounds of force (hanging a 23 kg
weight will do just fine). The yield strength of good music wire is about
85%-90% of the breaking strength. Thus, you would need to hang at least a
20kg weigh on the wire to see any straigtening.
One needs to be careful straigtening music wire by stretching with a
weight. If the yield point is exceeded by too much, the wire necks down and
weakens in some places (using stretching to straigten wire causes a permanent
slight reduction in the wire diameter), so the wire should be checked
afterward for sections that have thinned down by more than a few thousands of a
millimeter.
When I need to straighten music wire (guitar strings, usually), I stretch
it out tight. Then I further stretch it out by a bit more than 1% of the
original length (1% elongation or 1 cm for a 1 meter guitar string). This
takes about 45-50 pounds of force and usually gives a reasonably straight
piece of wire. Most of the time, a 0.013" guitar string breaks where the it
is wrapped around the bobbin at about 35-40 pounds of force (15kg-18kg of
hanging mass). However, the guitar string is still fairly straight even
then.
I hope this helps.
Leo
--- In Indoor_Construction_at_yahoogroups.com, Tapio Linkosalo
<tapio.linkosalo_at_...> wrote:
>
>
> Thanks to all for the tips on the F1D prop shaft. As I wrote before, I
> have a scroll of 0.35mm wire from Blashewicz (ukraine), so I tried to
> straighten that. I calculated that the pull force would be about 4 to 5
> kilos, pulled it up to 10kg (20 pounds), but it remained curved. I then
> tried the "rotate and pull through an inclined hole" -method, but this
> only produced a wire with a nice corkscrew pattern... :-) Luckily I
> found another short piece of 0.35mm wire, where I managed to salvage
> enough straight parts for 2 hubs; this probably originates from my time
> spent in Montreal.
>
> I guess I need to go to guitar string shop next. I did that several
> years ago when I started to build pennyplanes or F1M's. That was not a
> good experience, but the strings that I bought were rather mellow steel,
> easily bent, but also lost their shape too easily. Are there different
> brands of guitar strings, and what to look for to get "springy" wire?
>
>
>
> -Tapio-
>
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Received on Thu Jul 28 2011 - 08:33:14 CEST