Re: Tek Knob Project - scan and make

Chuck Harris

The knobs are plastic primarily for cost of manufacture.

The plastic defines the color, through-and-through, and
makes the knob feel neutral in temperature... the aluminum
hub provides the strength. Injection molding of knobs is
a mature, automated, process by which they could crank
out knobs by the millions without any operator intervention.

I had a friend that bought one such machine from a bankruptcy
auction, and he just had to fire it up. He filled the hopper
with some miscellaneous plastic pellets that came with the
machine, installed the mold, and filled the other hopper with
aluminum hubs, and set it going. Within an hour his hoppers
were empty, and he had more of these weird colored knobs than
he could ever sell.

However, aluminum, milled, or molded, and then painted
would be an acceptable solution. Its problems of conductivity
are shared with the plastic in that the setscrew, and the
underskirt, provide a pathway for electricity to the
operator. The ridges on the knob are high pressure points
where the paint will wear away eventually.

The conductivity isn't really a problem, as you are supposed
to be a "trained operator", and know that the scope must
be grounded.

Machining the knobs is simple, but highly repetitive. The
dies used in the injection molding process were machined,
and polished.

-Chuck Harris wrote:

I second the 10x for sharing!

Is there any reason some of these knobs could not be machined out of aluminum (or other material); other than non-originality?

Would aluminum pose any ESD or shock hazards? I see some knobs are made out of aluminum (completely). Why some, why some not?

Some, seem like pretty simple machining to me. Of course it's easier said than done (I am a novice still).



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