[sdiy] Why I was asking about UNEF etc.

[John L Marshall]

I use an aluminum block with guide holes. Place the block with the
appropriate hole against the hole to be tapped then insert the tap through
the block. This should yield perpendicular taps every time.

Take care,
John
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Pacific Northwest Synthesizer Meeting
August 9, 2003
www.sound-photo.com
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----- Original Message ----- 
From: "Simon Gatrall" <gatrall at pacbell.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, May 16, 2003 8:33 PM
Subject: Re: [sdiy] Why I was asking about UNEF etc.


> At 9:45 PM -0400 5/16/03, harrybissell wrote:
> >my $.02
> >
> >The tapped hole in the front panel is prlly fine for 1/4-32 threads...
> >
> >Aluminum usually taps poorly, so be very careful... a sloppy tap will
> >ruin the panel.
> >
> >If you can fit a jam nut from the back of the panel, that could work
> >as well...
> >
> >you might try getting knurled round nuts with slots like some 1/8"
> >jacks use...
> >or similar dress nuts...
> >
> >If you do the tapped panel thing... use a good dab of RTV silicone on the
back
> >of the panel to the pot body... one dab on a side would be fine.
> >This will really
> >discourage
> >the pot from rotating,
> >
> >IMHO if you do not use the anti-rotation tab of the pot... it WILL
eventually
> >start
> >to turn. The RTV could help a lot by making the rotation small until you
can
> >effect
> >a repair.
> >
> >OK that was $.04 worth
> >
> >H^) harry
>
> Harry's ideas about how to prevent the pot from rotating are good.
> There is however one problem that you (JH) may not have thought of
> until you actually start tapping the panels - if you are doing it by
> hand, it may be difficult to tap the holes normal to the panel.  You
> may end up with your pot shafts coming through the panel at random
> angles.  It's especially difficult as the hole size increases
> relative to the panel thickness.  A thick part with a small whole
> will tend to self-align the tap, but with a thin part with a large
> hole, it is easy to get the threads crooked.  With a 1/4" hole in a
> 1/8" panel, you're probably safe, but it could be tricky.  Certainly
> I would try the idea with some scrap before committing to a design
> based on your chosen assembly scheme.  You can also use a drill press
> to hold the tap vertical while you tap the panel (just use the drill
> press to guide the tap, don't turn it on).
> -- 
> Simon Gatrall
> gatrall at pacbell.net
>