ARC-5 Tuning Shaft Adapters
 

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.

Been trying to search the 'web (at the usual suspects such as
Fair Radio, Toronto Sales, etc.) but no joy. Yes, I know that
some consumer radio plastic knobs will fit, but those also
break very easy making the MTBFs very low indeed.

I would suppose that there is a mechanical description for the
splines and diameters but, alas, I ain't one of those. I've a feeling
that several mechanical hardware suppliers have them in stock.

Will appreciate any info, will trade assorted items for a couple of
metal adapters to metal shafts.

ARC-5 Tuning Shaft Adapters
 

you mite be about 50 years late
good luck
seel a used arc5 recver on ebay
ken uhrick
On 18 Sep 2006 21:03:02 -0700, "
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.

Been trying to search the 'web (at the usual suspects such as
Fair Radio, Toronto Sales, etc.) but no joy. Yes, I know that
some consumer radio plastic knobs will fit, but those also
break very easy making the MTBFs very low indeed.

I would suppose that there is a mechanical description for the
splines and diameters but, alas, I ain't one of those. I've a feeling
that several mechanical hardware suppliers have them in stock.

Will appreciate any info, will trade assorted items for a couple of
metal adapters to metal shafts.

ARC-5 Tuning Shaft Adapters
 

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.

ARC-5 Tuning Shaft Adapters
 

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]

ARC-5 Tuning Shaft Adapters
 

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

ARC-5 Tuning Shaft Adapters
 

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

ARC-5 Tuning Shaft Adapters
 

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.

ARC-5 Tuning Shaft Adapters
 

ORIGINAL MESSAGE:

On 18 Sep 2006 21:03:02 -0700, "
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.

------------ REPLY FOLLOWS ------------

Agreed, those are among the best variable capacitors ever made.

My first radio in 1957 was an ARC-5 a friend gave me. It had a shaft
made from a piece of 1/4 inch copper tubing, carefully drilled out so
it was a very tight force fit. No glue, set screws or anything like
that, just a very tight fit that had to be driven on with a hammer. I
used that RX for a couple of years and the shaft performed perfectly.

Hope this helps.

Bill, W6WRT