I like the aluminum knob I made for the PTO on my Corsair II. My lathe
is too light to do a good job knurling so I don't offer it for
production. Perhaps if I had a sturdier lathe, or made a knob to take
the rubber sleeve. I would rather go hire a machine shop to make a
bucket of them though. I might own a sturdier lathe in a year or two.
Alternatives I see, McMaster-Carr offers aluminum and steel knobs
without cranks in 2" diamter 1-1/8" standoff from the panel, not drilled
for shaft or set screw 6077K14 for under $15 in my vintage catalog and
in stainless steel 6077K42 for less than $25. These would be fairly
weighty. Or they offer a 2" diameter knob (material not listed) with a
finger tip spinner for a quarter inch shaft with set screw, 7354K13 for
under $4.
Mouser offers from Alcoswitch, machined aluminum knobs 1-3/4" diameter
for quarter inch shaft with set screw with finger spinner, natural
finish for $24.24 black for $21.50 in my lat 2008 catalog that is handy
to the computer. 506-KN1751AS1/4 or 506-KN1751BS1/4. Or from Eagle
Plastics with dual set screws and a crank knob 1-3/4" diameter, 450-1755
for $8.55.
73, Jerry, K0CQ
On 4/12/2010 1:36 PM, David Goncalves wrote:
You have it right...compared to the forces applied to the encoder from
the user (hanging your hand on the knob waiting for the other guy to
stop sending CQ, cranking through the band using one finger, etc) the
additional forces from the aluminum knob. I made a quick measurement
here with something similar, and got numbers within 50-80% of the
loading specifications. I wouldn't have a problem replacing the plastic
with the metal one, as long as it looked nice enough.
Not an experience I have enjoyed yet - all my TenTec stuff is either
computer control or PTO. I'm saving up my pennies, though!
David Goncalves
W1EUJ
On Mon, Apr 12, 2010 at 10:45 AM, Dr. Gerald N. Johnson
<geraldj@weather.net <mailto:geraldj@weather.net>> wrote:
I'd think that the side thrust from running a finger just under the knob
could be greater...
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