Andrew VK3BFA wrote:
wrote:
Does anyone have or can they direct me to a couple of "splined"
tuning shaft adapters that fit the ARC-5 Command Set receivers?
I'd like to adapt some of the ganged variable capacitors from
those sets into some homebuilt equipment...lovely antibacklash
gear reduction on them.

Hi Len,
nope - rare as rocking horse manure. I machined ones from brass rod -
receiver end, a press fit on the splines, other end, quarter inch for
knob.

Andrew VK3BFA.

Thanks, Andrew...I got that impression after several hours of web
surfing. :-) :-(

My 1948-acquired Command Set surplus stock has slowly
withered away ($6 for receivers, $12 for transmitters, $18 for
antenna tuning unit-modulator-Tx dynamotor at that time).
I'd gotten 4 of the tuning "knob" adapters back then, 2 got
traded-sold, 1 remains on a 6-9 MHz receiver, and 1 is lost
somewhere unknown.

Beautiful anti-backlash worm drive on those ganged capacitors.
Would be good for tuning anything.

Not being a machinist I was hoping someone would come up
with the correct words to describe the splined whatsis so that
I could haunt a few mechanical parts suppliers for something
that would mate smoothly with it. I tried some copper tubing
(pressed over splines) with marginal success (several
diameters, easy to get at do-it-yourself stores for various
small water piping uses) but those bend rather easily. [it's not
too swift when one's home machine shop consists of a Big Lots
table top drill press...:-) ]

I did come across a Magnificent website with Great pictures of
WW2 radio equipment in US military aviation: http://aafradio.org
Now there is a Collector! [and a consultant at the Smithsonian
Air and Space Museum]

Len Anderson wrote :
Not being a machinist I was hoping someone would come up
with the correct words to describe the splined whatsis so that
I could haunt a few mechanical parts suppliers for something
that would mate smoothly with it. I tried some copper tubing
(pressed over splines) with marginal success (several
diameters, easy to get at do-it-yourself stores for various
small water piping uses) but those bend rather easily. [it's not
too swift when one's home machine shop consists of a Big Lots
table top drill press...:-) ]
============================
Not knowing the equipment being discussed ,I could suggest the following
general method of extending a 6 -6.35 mm shaft . (6.35mm equals 1/4 inch)

Take 2 (if possible identical) non metallic knobs for the shaft diameter
concerned ,for example the push-on potmeter knobs found on almost any
VDU or older TV and BC radio sets , used to push onto splined potmeters .
Equipment from Asian origin is always metric ,hence shafts dias are 6 mm .
Fit the 2 knobs concentrically piggy back ,with either epoxy or 2 or 3
bolts /nuts either metallic or non-metallic (say nylon).

Push/fix 1 knob onto the splined shaft to be extended.
Fit tubular/solid extension shaft into other side.

If alignment with front panel opening is a problem , glue flexible
material (for example rubber ,dense foam or expanded polystyrene )in
between the 2 knobs . Of course all this provided there is enough
space in the enclosure.

This method is also very suitable for applications involving components
with a rotary shaft which should be kept free from ground ,like in
antenna matching units (tuners) .

If the to be driven shaft has a 1/4 inch diameter the mating knob must
suit this ,but the other knob can be for a 6mm dia shaft and final front
panel knob There is a lot of flexibility.

Frank GM0CSZ / KN6WH

Len Anderson wrote :
Not being a machinist I was hoping someone would come up
with the correct words to describe the splined whatsis so that
I could haunt a few mechanical parts suppliers for something
that would mate smoothly with it. I tried some copper tubing
(pressed over splines) with marginal success (several
diameters, easy to get at do-it-yourself stores for various
small water piping uses) but those bend rather easily. [it's not
too swift when one's home machine shop consists of a Big Lots
table top drill press...:-) ]

Len, today is your lucky day. I have ONE splined whatsis, the tuning knob
that was included in every maintenance kit for the BCxxx series. Steel with
a heavily knurled 1/2 inch knob.

Send me your snail mail address, pretty sure I'm not going to be using it.

W4ZCB

Highland Ham wrote:
Len Anderson wrote :
Not being a machinist I was hoping someone would come up
with the correct words to describe the splined whatsis so that
I could haunt a few mechanical parts suppliers for something
that would mate smoothly with it. I tried some copper tubing
(pressed over splines) with marginal success (several
diameters, easy to get at do-it-yourself stores for various
small water piping uses) but those bend rather easily. [it's not
too swift when one's home machine shop consists of a Big Lots
table top drill press...:-) ]
============================
Not knowing the equipment being discussed ,I could suggest the following
general method of extending a 6 -6.35 mm shaft . (6.35mm equals 1/4 inch)

Take 2 (if possible identical) non metallic knobs for the shaft diameter
concerned ,for example the push-on potmeter knobs found on almost any
VDU or older TV and BC radio sets , used to push onto splined potmeters .
Equipment from Asian origin is always metric ,hence shafts dias are 6 mm .
Fit the 2 knobs concentrically piggy back ,with either epoxy or 2 or 3
bolts /nuts either metallic or non-metallic (say nylon).

Push/fix 1 knob onto the splined shaft to be extended.
Fit tubular/solid extension shaft into other side.

If alignment with front panel opening is a problem , glue flexible
material (for example rubber ,dense foam or expanded polystyrene )in
between the 2 knobs . Of course all this provided there is enough
space in the enclosure.

This method is also very suitable for applications involving components
with a rotary shaft which should be kept free from ground ,like in
antenna matching units (tuners) .

If the to be driven shaft has a 1/4 inch diameter the mating knob must
suit this ,but the other knob can be for a 6mm dia shaft and final front
panel knob There is a lot of flexibility.

Frank GM0CSZ / KN6WH

Good tip, Frank! Thanks but I've tried that before. Depends on the
polymer of the knobs...some can take moderate flexure (usually
polypropylene?) but others (polystyrene) can't.