Re: how to finess a knob off

Don Black <donald_black@...>

We used to do a similar think with tight TV knobs. We used a strong length of twine (string - builders line is good) and just wrapped a single turn around the shaft behind the knob. Then pull both ends hard away from the panel and the knob should come off. It stops marking from something like a screwdriver, just look at each situation to make sure it won't do anything bad like snap a thin section knob. usually works a treat.

Don Black.

On 17-Jun-13 12:02 AM, Brad Thompson wrote:

On 6/16/2013 9:28 AM, Jerry wrote:
> hello all/ need some Ideas how to remove a knob on inner shaft of a
> horizontal position control /inner is the 10x switch/needed to be
> removed to access the screws under the thin nameplate panel to remove a
> board for repair / board is broken /but pulled to hard and shaft now
> pulled out of control/ hopefully repairable/ its not set screw type knob
> just the splitshaft type knob still cant pull it from shaft/ any ideas
> appreciated

By coincidence, I just posted the following suggestion to another
newsgroup. While I doubt that it's applicable to Jerry's predicament,
it may help someone else avoid damaging an expensive or hard-to-find
instrument control knob. [1]

Before you damage a knob, try this:

If the knob in question is fastened to its shaft with a setscrew,
remove the screw and place a droplet of Kroil or other penetrating
oil in the setscrew hole.

Next, obtain a short length (i.e., a few inches) of ribbon cable
as is used in computer disk-drive cables. Using a sharp knife,
separate the conductors in the cable's center, approximately
halfway along the cable.

Push the ribbon cable's opening over the knob and slip
the conductors under the knob between the knob and panel.
Grasp the cable's free ends and gently pull. With any luck,
the knob should slide off without damage.

In contrast to the "pry with a screwdriver" approach,
the ribbon cable applies even pressure to two sides of
the knob.


Brad AA1IP

[1]: note that some knobs are held to their shafts by a
split nut hidden beneath a removable cap set in the
knob's center. Pry off the cap and you'll find a brass
insert that clamps to the control's shaft.

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