[sdiy] Why I was asking about UNEF etc.

[Tim Parkhurst]

Hi JH,

Personally, I'd say you're asking for trouble by threading a pot directly
into an aluminum panel. In a relatively thin sheet of aluminum, you're not
going to get too many threads. For example, even if the panel were 1/4"
thick (about 6.3mm), you are only going to get 8 threads. If the panel is
1/8", you're only getting 4 threads. You won't be able to get enough torque
on the pot to hold it in place reliably and this means that it is going to
be VERY easy for the threads to strip. Also, even if most of the pots hold
in place okay, if you strip out just one you're going to have to put a nut
on it anyway. Are you using panel nuts? They're special purpose nuts that
are very thin. Again, they'll only have 4 or 5 threads, but because they're
made of steel they are much stronger and will hold just fine.


Tim Servo (mechanical engineer kind of guy)

"To announce that there must be no criticism of the President, or that
we are to stand by the President, right or wrong, is not only unpatriotic
and servile, but is morally treasonable to the American public."
-Theodore Roosevelt

************************************************
> -----Original Message-----
> From: jhaible at debitel.net [mailto:jhaible at debitel.net]
> Sent: Friday, May 16, 2003 7:07 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Why I was asking about UNEF etc.
> 
> Thanks to all who answered - I think I have understood this
> now.
> 
> Why have I been asking?
> 
> I have made a little redesign of my 3200 front panel.
> The 16mm knobs for the temperament pots were too bulky,
> compared to the 21mm knobs I'm using for the pull-pots
> of the regular parameters.
> 
> Now I found a nice little 11mm knob that matches the
> bigger ones - so cute and tiny, and they fit on
> a 1/8" shaft of these Bourns 9mm conductive plastic
> potentiometers. (Bourns 3310Y)
> And while this _does_ work when I mount the pots with
> a nut, the drawback is that I must avoid the knob
> to touch this nut. (The knob is larger than the nut,
> so it will be covered. But it's not large enough for
> nut to dissapear inside the inner hole of the knob's
> skirt.)
> 
> So I wonder if I could just make a thread into the
> aluminium panel and crew the pots in from the rear,
> _without_ a nut on the front panel.
> 
> I don't know if this will work, becaus ethe pot will
> get some rotational force from turning the knob in
> normal use, so I fear I could loosen the pot in the
> front panel, if it's just screwd in from the rear.
> It _might_ work, because the plastic thread of the pot
> might give enough resistance if it's srewd in with enough
> force; and I also have locking washers I can use (also
> on the back side of the front panel).
> 
> Is there any chance this will work?
> If it doesn't, I can still apply the nuts from the
> front, so I guess I don't take any risk.
> But maybe somebody has tried this before and can tell
> me if it will work, or if it won't.
> 
> (Of course I cannot predict the end position of
> the rectangular potentiometer body if I do this,
> but this doesn't hurt becaus eth epots are so tiny,
> and sealed.)
> 
> Any helpful comments ?
> 
> JH.
> 
> 
> 
> 
> 
> 
> -------------------------------------------------
> debitel.net Webmail



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