I am working on an idea that involves a guide rod (3 actually) sliding back
and forth in a "bushing" with some degree of accuracy. Actually the guide
rod would be in two different bushings about 2.75 inches apart. Side load
would be very light, but there would be some. (less than inch pounds in
most cases) During the course of use the guide rod might have to move 0.050
40-50 times, and have continuous movement from .001 to .009 for a 20 minute
job.
Some small amount of side play would be tolerable but experimentation is
required to determine how much. Greater for some jobs. The idea is that
the bushing can be pressed out and replaced periodically as needed.
1. If you were to do this ideally what would you use for the bushing and
the guide rod?
2. If the ideal materials where not available what would you use that is
commonly available?
3. What would you use that is commonly available and cheap?
Due to space limitations I am looking at a guide rod diameter of
approximately .25, but I could redesign for up to .375. Extra mass could
have a negative impact on the intended direction of travel, but mass could
be removed elsewhere.
I was thinking of something like this for the bushing. The guide rod will
be fixed and not rotate in the bushing. Just slide back and forth. The
guide rod will be vertical. Side load (minimal) will be in any and all
directions at one time or another.
http://tinyurl.com/yjub9ak
And something like this for the guide rod.
http://tinyurl.com/yzhmvlm
I would add that the over tool body would be aluminum (for weight) and the
guide rod would be fixed into the carriage or moving part of the tool
directly either by a press fit or possible with green Loctite bushing and
sleeve locker. This would make a stainless alloy for the guide rod
desirable.