[sdiy] Why I was asking about UNEF etc.

[jhaible]

Hi Theo,

thanks for shedding some light; to adress this clamping / vice stuff.

> When the pot is used with a nut, the rotation stop is primarily there for
> assembly purpose.
> While tightening the nut something has to absorb the rotational force
> applied.
> You don't like the PCB pins to do this job, this is where the rotation
stop
> comes in.

My hand will do the job (no jokes about the hand jobs, please!).
No PCB mounting here, of course.


> When you have the thread in the front panel you don't have the clamping
> force between pothousing and front panel to absorb rotation forces.
> This is the big difference between the two methods.

I guess this is the reason for my bad "gut feeling". But you have
pinned it down. Not 100% sure about the difference, though.
But the plot thickens.

> On the bright side the rotational forces involved are quite small.
> If you put a rotation stopping "star" washer between the pothousing and
the
> front panel you're probably ok.
> The "star" washer eats itself in both the front panel and the pot housing
> resulting in a form-closed assembly.

This is exactly what I menat with "lock washer". Is star washer the same
thing? This will be clamped between pot and panel. Not 100% sure
if it's as good as the normal solution, though.


> I tried 3310 pots for some modules.
> Think the 3.15mm plastic shaft is just too thin.
> The pots feel wobbly if you put a knob on them, not a good feel IMO.

I've tried them with RS Components knobs (259-6812) and this
combination just feels great, IMO. But these knobs are really tiny,
only 10.2 mm height, not much left to wobble here.

I had used thin, but rather high knobs with 3310's on another project,
and yes, there it was a little wobbly.


> Actually I disliked the 3310 that much that I decided to widen the holes
in
> all the 20 Schaeffer front panels I  already had made to fit a different
> model pot.
> I now use 174 series from Vishay for my modular.
> (Anyone wants to buy a pile of 3310Y 10K and 100K?)
>
> If its is for cheap small pots I would just consider the 11mm and 14mm
> snap-in pots of the RK11 and RK14 series.
> These are cheaper and don't wobble like the 3310 do.

You won't believe it, but I'm doing the exact contrary. I have already
soldered 25 of these 11mm pots onto a piece of veroboard, matched
the holes on the front panel, and bought all the knobs (not cheap). But
I think everything that fits on a 6mm axis is too bulky for this
application.
Now, with the 9mm pots and 11mm knobs, I have exactly that PS 3200
touch I was looking for.

JH.