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<div class="moz-cite-prefix"><font face="Arial">You probably nailed
it, Steve O, thanks!</font></div>
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<div class="moz-cite-prefix"><font face="Arial">Measured the water
displacement of one existing shoe. Then measured weight of that
one shoe (Zamak?) as 12 ounces. Calculated weight of a shoe if
aluminum would be 4.2 ounces. So everything jives within the
ballpark range of relative densities for Zamak and aluminum. <br>
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<div class="moz-cite-prefix"><font face="Arial">I'm doing more web
research into use of Zamac for centrifugal clutch shoes. Seems
to be used a lot. But most employ a thin bonded friction
facing. A disc could probably be cast from a 4-pound Zamak
billet ($13), then machined on a lathe like Steve W. suggested,
then cut into four pieces to replicate the shoes I need.</font></div>
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<div class="moz-cite-prefix"><font face="Arial">Two wild cards
remaining are whether there was a friction facing originally
installed on the shoes that got burned away; and if the bearings
got ruined because of the high heat. I plan to pull the clutch
this weekend to check.</font></div>
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<div class="moz-cite-prefix"><font face="Arial">And thanks for the
links to new clutches, Thomas. Trying to avoid this route
because of high cost, but might be a last resort.</font></div>
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<div class="moz-cite-prefix"><font face="Arial">- Richard</font></div>
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<div class="moz-cite-prefix"><font face="Arial">On 4/23/2021 7:01
AM, Stephen Offiler wrote:<br>
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<blockquote type="cite"
cite="mid:CAP6upcjti1zOGuit4KjB0ypp95KUsT9WRzLTbBeHrUukgcjV5g@mail.gmail.com">
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<div dir="ltr"><font face="Arial">I have to wonder if it's zinc
(or Zamak alloy). I can't say I've ever seen aluminum used in
a friction application. It just seems that it would gall and
wear rapidly. Zinc has much higher density than Al and you
did mention that it seemed heavy. Finally, zinc melts at a
lower temperature, roughly 700F vs. 1200F and you mentioned
that it melted.</font>
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<div><font face="Arial">If you look around the 'Net you'll find
various ways to determine whether it is Al or Zn/Zamak.
Oven cleaner is one trick. That stuff is lye-based and will
aggressively attack aluminum but not zinc.</font></div>
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<div><font face="Arial">SO </font></div>
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<div class="gmail_quote">
<div dir="ltr" class="gmail_attr"><font face="Arial">On Fri, Apr
23, 2021 at 3:01 AM Steve W. <<a
href="mailto:swilliams268@frontier.com"
moz-do-not-send="true">swilliams268@frontier.com</a>>
wrote:<br>
</font></div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><font
face="Arial">Richard Walker wrote:<br>
> <br>
>> Those wouldn't be that hard to turn on a lathe. I'm
guessing the <br>
>> originals were cast aluminum alloy, then final
machined. Could turn a <br>
>> solid piece with the step and slots for the
springs. Then cut them <br>
>> apart and finish the ends to size. If I had my
lathe still set up I'd <br>
>> do it. <br>
> <br>
> <br>
> Thanks, Steve. Already considered that as one option,
have lathe and <br>
> large hunks of aluminum round in my scrap bin. Springs
could be <br>
> generic, guesstimating the original tension by wire
gauge and coil <br>
> diameter. The wild card is whether the type alloy used
is critical to <br>
> the clutch's proper operation - its friction against
the cast iron outer <br>
> drum. The shoes seem noticeably heavier than what I'd
expect typical <br>
> aluminum to weigh. At the worst I'm out an afternoon's
machining to try <br>
> this approach. <br>
> <br>
> Wet pine needles got lodged between the chipper disc
and its housing, <br>
> which ultimately bound it up. As this was in progress,
the centrifugal <br>
> clutch started slipping and heating up, which I didn't
notice at first. <br>
> Eventually heat totally melted one of the four aluminum
shoes.<br>
> <br>
> Been the best mid-size chipper I've ever used. Billed
as an AV (All <br>
> Vegetation) unit by Vandermolen, it will literally chip
and shred <br>
> practically anything. First by the four knives in the
disc, then into a <br>
> hammer-mill chamber with swinging flails.<br>
> <br>
> <br>
> Richard<br>
> <br>
</font>
<font face="Arial"><br>
It could be some odd alloy but I would think it's a 300
series casting. <br>
Unless they used a slug of something inside the casting.<br>
</font>
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-- <br>
Steve W.</font></blockquote>
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