On Tue, 26 Mar 2013 15:19:52 -0400, "Existential Angst"
wrote:

OK,

Apropos of my wiper Q, here's more info, with another Q.....

Since I don't think this wiper thing is going to be so easy to solve, and
since from a sliding/friction pov it don't get much worse than alum on/in
alum, I'm experimenting with making the slider ITSELF out of a
nylon-ish/UHMW material. Altho I would still like a wiper, a plastic slider
(and the lubricity thereof) should intrinsically help, from a
friction/galling pov.

So the Q is: what would be a good substitute for the alum slider? I'd like
a good combo of strength and lubricity, as stuff is attached to this slider,
via 10-24 screws, 3/16 pins, etc. The 10-24 screws will not be threaded
into the slider itself, but rather thru the slider and into another pc of
substantial alum.

I've always liked nylon, delrin, teflon. Nylon seems to be a kind of ref.
std, ito plastic strength, durability, and it seems that altho it doesn't
have the lubricity of delrin, it's OK. Would delrin be better? Anything
else?

fyi, the actual size of this particular slider is approx. 3/8 x 3/4, with a
1/8x1/8 rabbet on each side (so the captured sliding part is 1/4 x 3/4),
with a 4.5" L

Any class of materials I should specifically avoid?

Idears, opinions?

I suppose I could test various materials, by buying or making something of a
power hacksaw, and just let various materials reciprocate for a few days,
see what stuff looks like at the end. Hopefully I won't have to go that
route, tho.
For the best combination of slippery and mechanical strength Delrin AF
would be best. It is very slippery, more rigid than UHMW, machines
easily without making problematic chips, is easy to deburr without
making another burr. It's expensive but then you would only need to
make it once. It is about as slippery as UHMW.
Eric

wrote in message
...
On Tue, 26 Mar 2013 15:19:52 -0400, "Existential Angst"
wrote:

OK,

Apropos of my wiper Q, here's more info, with another Q.....

Since I don't think this wiper thing is going to be so easy to solve, and
since from a sliding/friction pov it don't get much worse than alum on/in
alum, I'm experimenting with making the slider ITSELF out of a
nylon-ish/UHMW material. Altho I would still like a wiper, a plastic
slider
(and the lubricity thereof) should intrinsically help, from a
friction/galling pov.

So the Q is: what would be a good substitute for the alum slider? I'd
like
a good combo of strength and lubricity, as stuff is attached to this
slider,
via 10-24 screws, 3/16 pins, etc. The 10-24 screws will not be threaded
into the slider itself, but rather thru the slider and into another pc of
substantial alum.

I've always liked nylon, delrin, teflon. Nylon seems to be a kind of ref.
std, ito plastic strength, durability, and it seems that altho it doesn't
have the lubricity of delrin, it's OK. Would delrin be better? Anything
else?

fyi, the actual size of this particular slider is approx. 3/8 x 3/4, with
a
1/8x1/8 rabbet on each side (so the captured sliding part is 1/4 x 3/4),
with a 4.5" L

Any class of materials I should specifically avoid?

Idears, opinions?

I suppose I could test various materials, by buying or making something of
a
power hacksaw, and just let various materials reciprocate for a few days,
see what stuff looks like at the end. Hopefully I won't have to go that
route, tho.
For the best combination of slippery and mechanical strength Delrin AF
would be best. It is very slippery, more rigid than UHMW, machines
easily without making problematic chips, is easy to deburr without
making another burr. It's expensive but then you would only need to
make it once. It is about as slippery as UHMW.
Eric

I just happen to have an AIN plastics by me (part of the Thyssen Krupp
CorPirate juggernaut), went over there, asked about Delrin AF (various
types, btw, of "blends"), it's $250/sq ft.... !!!!!! Holy ****....

MDS Nylons (molybdenum disulfide impregnated/lubricated), and some other
stuff a guy there recommended, is $25/sq ft.

I brought some my scrap collection, most of which he identified. I have some
nice HD polyethylene, which is basically white cutting-board material.
Corian, iiuc, is also a HDPE.
My HDPE scraps feel like nylon, but more slippery. Should do me for now,
he's going to try to throw me some factory cut-offs/drops, to try out.
We'll see what happens.

For kicks, look up Vespel, by DuPont.... It's about as expensive as gold,
and places that carry it keep it in a vault.... holy ****.....

These materials are big chemical bidniss, sophisticated stuff.
Unfortunately, most of it is not supplied in alum-type cross-sections, so
you gotta cut most stuff out of sheet, plate, another pita.
--
EA

On Wed, 27 Mar 2013 22:33:47 -0400, "Existential Angst"
wrote:

wrote in message
.. .
On Tue, 26 Mar 2013 15:19:52 -0400, "Existential Angst"
wrote:

OK,

Apropos of my wiper Q, here's more info, with another Q.....

Since I don't think this wiper thing is going to be so easy to solve, and
since from a sliding/friction pov it don't get much worse than alum on/in
alum, I'm experimenting with making the slider ITSELF out of a
nylon-ish/UHMW material. Altho I would still like a wiper, a plastic
slider
(and the lubricity thereof) should intrinsically help, from a
friction/galling pov.

So the Q is: what would be a good substitute for the alum slider? I'd
like
a good combo of strength and lubricity, as stuff is attached to this
slider,
via 10-24 screws, 3/16 pins, etc. The 10-24 screws will not be threaded
into the slider itself, but rather thru the slider and into another pc of
substantial alum.

I've always liked nylon, delrin, teflon. Nylon seems to be a kind of ref.
std, ito plastic strength, durability, and it seems that altho it doesn't
have the lubricity of delrin, it's OK. Would delrin be better? Anything
else?

fyi, the actual size of this particular slider is approx. 3/8 x 3/4, with
a
1/8x1/8 rabbet on each side (so the captured sliding part is 1/4 x 3/4),
with a 4.5" L

Any class of materials I should specifically avoid?

Idears, opinions?

I suppose I could test various materials, by buying or making something of
a
power hacksaw, and just let various materials reciprocate for a few days,
see what stuff looks like at the end. Hopefully I won't have to go that
route, tho.
For the best combination of slippery and mechanical strength Delrin AF
would be best. It is very slippery, more rigid than UHMW, machines
easily without making problematic chips, is easy to deburr without
making another burr. It's expensive but then you would only need to
make it once. It is about as slippery as UHMW.
Eric

I just happen to have an AIN plastics by me (part of the Thyssen Krupp
CorPirate juggernaut), went over there, asked about Delrin AF (various
types, btw, of "blends"), it's $250/sq ft.... !!!!!! Holy ****....

MDS Nylons (molybdenum disulfide impregnated/lubricated), and some other
stuff a guy there recommended, is $25/sq ft.

I brought some my scrap collection, most of which he identified. I have some
nice HD polyethylene, which is basically white cutting-board material.
Corian, iiuc, is also a HDPE.
My HDPE scraps feel like nylon, but more slippery. Should do me for now,
he's going to try to throw me some factory cut-offs/drops, to try out.
We'll see what happens.

For kicks, look up Vespel, by DuPont.... It's about as expensive as gold,
and places that carry it keep it in a vault.... holy ****.....

These materials are big chemical bidniss, sophisticated stuff.
Unfortunately, most of it is not supplied in alum-type cross-sections, so
you gotta cut most stuff out of sheet, plate, another pita.
It kinda depends what your application is whether you want to spend
the money. I had an application that required a plain bearing running
at fairly high speed without lubrication. The original bearing was
nylon. It lasted for a for a while. I next tried MDS filled nylon.
That bushing lasted about 9 hours. I finally used Delrin AF and the
bushing has over 50 hours on it. This bearing (bushing) is used as a
tensioning idler on a rototiller. I kept wasting time with inferior
materials. So decide which material will work best and how many times
you want to make the thing and how much your time is worth.
ERic