"Searcher7" wrote in message
...
On Apr 12, 5:38 pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message
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On Apr 12, 3:23 pm, "Ed Huntress" wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in
messagenews:Xns9EC59A0326DF7lloydspmindspringcom@2 16.168.3.70...
"newshound" fired this volley in
:
Nope, Tim is right
Besides that, hard on hard of the _same_ hardness often induces
galling.
True, when neither journal nor shaft is hard enough to resist it.
Galling
is
the primary reason that soft steel on soft steel is such a disaster.
--
Ed Huntress
Considering the OP's low-end fabrication equipment, do you think
hardware store CRS or aluminum rod on nylon would be good enough?
These machines aren't going to be beaten up in arcades any more.
jsw
Likely so, but I want to have a better idea of how that rod moves around.
The advantage of nylon or Teflon would be that replacement bearings would
be
easy. If the loads are light, as I suspect, there's no reason to go to
hard,
unless slop in the bearing is a big problem.
The way he has it arranged now it looks like the fairly light loads are
concentrated at the contact points, which would be deadly for a plastic
bearing. It needs a bigger bearing surface -- a ball and socket, or
something like that.
But I'm not sure I have the movement figured out correctly.
--
Ed Huntress
I've been trying to figure out how to explain this without just
repeating what I said above.
Imagine a 1/16" metal sheet. Drill a 1/4" diameter hole into it. Stick
the end of a rod into it.
Allow the rod to turn back and forth over a 20° range maximum.
The rod will be at a diameter that will not allow it to turn freely
but without any discernible play along any singular plane.
I'd draw a 3D picture of what I just said, but that would be asking
too much of MsPaint.
Here is a picture of a new and a worn joystick.
http://i290.photobucket.com/albums/l...ystickWear.jpg
That center hole has widened to a larger diameter on the worn
joystick. As a result there is discernible play along any singular
plane.
I'm considering three design change, but that is not what this is
about. This is about the best materials to use for the parts that move
against each other.
From what I'm being told above, if either the rod *or* the hole were
made of Delrin the widening of the hole would occur at a slower rate
than the conventional metal to metal as shown.
Thanks.
Darren Harris
Staten Island, New York.
First I'd try one of these.
http://www.mcmaster.com/#sleeve-bearings/=byhhrr
It is for sheet metal a little thicker than yours, but for $1.61, whadda ya
have to lose.
Paul K. Dickman