I am going up on the Teflon and spacer thickness to 3/8 inch from 1/4 inch.
Too hard to fasten the 10-32 throttle cable to the button.
It makes a marginal connection to a button only 1/4 inch thick.
If you use the 3/8 Teflon then McMaster Carr has off the shelf steel
spacers
that will work as buttons. Much, much, much easier than making your own.
You would need a lathe anyway. I spent four hours today fooling
around trying to make a good button.
McMaster Carr 3/4 inch OD 3/8th inch long 5/16th ID steel spacer part
number 92415A455 $3.32 well worth it.
Also buy the precision ground blanks in Teflon. McMaster Carr
part number 9711K2 for 3/8 thick 4 inches wide and 12 inches long.
Expensive but well worth it. +-.005
I got some 1/4 Teflon sheet and the thickness was all over the place.
Too wavy. Sure to lead to problem. +.038 - .019 in 3/8 thickness.
I thought a lot about this and this is still the best way to
go. It is way over kill but you don't want the throttle cable
to become disconnected from the slide. One of those things
you don't want to fool around with.
Paul Lamar
Here is the 3/8th thick on the left and the 1/4 inch thick on the right.
Much more robust connection between the throttle cable and the slide.
Paul Lamar
Paul,
OK here's the problem. You mention it in one of your later postings. Your
water pump belt takes out your throttle cable on take off, or worse just as
you decide you need to overshoot, what happens ? Might I suggest placing
your button as far from the throttle cable end as possible, 2 1/2" or so.
Bore the hole for the cable oversize and install a Teflon tube. Insert a
compression spring into the tube and run the cable through the center of
both the tube and the spring. If the cable fails, the spring should push the
throttle slide full open. If there isn't enough room in the slide for the
tube perhaps it could be incorporated into the spacer.
John
Yes I think that would work but do you really want a spring on your
throttle? The friction lock then becomes essential and a strong
one at that. That would also be a major redesign. I think you would
need a spring with a free length of 4 inches or more to accommodate
two inches of travel. Another way is to put a button on the other
end of the Teflon slide and a screen door spring pulling on a tension wire
running through another small hole in the other end of the spacer.
Easier to build and no redesign necessary.
A belt shield is a good idea in any event. Here is one Chuck Dunlap installed.
Paul Lamar
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