The Ultimate CHEAP Wooden Linear Slide & other Rambelings

[scratch_6057]

OK, I really haven't had anything to say lately so
I’ve been keeping my mouth shut.

I keep seeing this

"Hello scratch_6057 it appears that you have not posted
on our forums in several weeks, why not take a few moments
to ask a question, help provide a solution or just engage
in a conversation with another member in any one of our forums?"

SO, I'll post something even though I STILL really don't have
ANYTHING to say.

The Ultimate CHEAP Wooden Linear Slide
http://www.rockler.com/product.cfm?page=198&cs=1

With enough coats of something THICK to seal it and take the
slop pot and then LOTS of sanding / finish work, someone may
find it usable on a VERY basic Entry Level machine. Might
actually be useful to someone who is just wanting to sample
what CNC is all about, I wonder if they would work with NEMA 17
Floppy Drive steppers?

On a slightly more serious note, I know it’s been brought up on the Zone
from time to time but I’ve never really seen a positive response (if there are any).
So I’ll ask again (please don’t SHOOT ME, or run me off). "Has anyone done any
work with HDPE / UHMW Plastic for supported slides?" I came across some
0.125 Wall UHMW ‘U’ or ‘C’ Channel on mcmaster.com Part Number:8672K31
Leg Length 3/4" (Height) Outside, Base Length 1-1/4" (Width) Given
the above measurements the inside of the channel should be 5/8 (height) by 3/4 (wide).
Seems to me that could be mounted to a base (counter sunk screws thru the bottom)
for guide ways then use 3/4 by ??? HDPE or UHMW for the rails attached to a table.

The Channel Costs $2.04 (8 Ft & up) - $2.36 per ft. (2 - 7 ft)
3/4" By 1" for rails is
High-Density Polyethylene (HDPE) 8671K15 $1.66 per Ft.
Ultra-High Molecular Weight Polyethylene (UHMW) 8702K112 3.08 per Ft.

(FYI HDPE on HPDE slides rather well, almost as good as fresh 'Dog Squat' in the yard)

I got my copy of the Rockcliff plans a couple of days ago, that’s what got me
thinking in this direction.

[bp092]

Linear wood rails? How could you ever compensate for expansion and contraction? It doesn't matter if you dip the thing in a thick epoxy, it will expand and contract depending on moisture/temperature changes no matter what. Even if its a cheap machine it probably wouldn't even be good enough for that.

[pminmo]

UMHW is used for bearings against polosed/smooth metal surfaces as is acetel. Look at 8020's bearings. It does wear, so if the surface is not polished it will wear more quickly.