Machining Characteristics of Plastics
 

Go over to rec.crafts.metalworking and post your question there. While the
group is nominally about metalworking, the machinists there know a lot about
the machining characteristics of various materials like the plastics.

Tom Dacon

"Geoffrey W. Schultz" wrote in message
. 16...
I have a KISS wind generator that develops vibration at certain wind
speeds. The problem is that there's a PVC fitting that goes over a 2"
stainless schedule 40 support pipe that is loose fitting. I want to
machine one with a sleeve bearing on a lathe and make it out of plastic.
However, I really don't have any experience machining plastic, I've been
looking at www.mscdirect.com under Raw Materials/Plastic Material/Rods for
3" material. To keep costs under control I'm looking at the following:

Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall strength
of
these would be greatly appreciated.

-- Geoff

Machining Characteristics of Plastics
 

It's definately a blade balance issue, but I've carefully run through
the balancing instructions and I can't find any blade that's heavier
than the others. I'm sure that there are some harmonics that are
causing it, but I haven't been able to figure out how to balance it.

None of the PVC fittings that came with it provided what I would call a
snug fit. There was a good 1/16" clearance around the pipe, which
certainly is enough to allow vibration.

-- Geoff


"Doug Dotson" wrote in
:

What kind of speeds are producing this effect? My KISS doesn't
produce any significant vibration up to 30 kts or so. That is as fast
as I have run it. Have you checked the balance of the blades? A
slight unbalance in the blades might induce a vibration in the
mounting. I chose to use 2" SS tube rather than sched 40 pipe. The
PVC fitting is a snug fit. The KISS came with an assortment of
fittings to fit a number of different kinds of pipe. If the 2" tube
fits the KISS better than the sched 40 pipe, perhaps attaching a short
length of 2" tube to the top of the pipe for mounting would be a
simpler solution.

Doug
s/v Callista

"Geoffrey W. Schultz" wrote in message
. 16...
I have a KISS wind generator that develops vibration at certain wind
speeds. The problem is that there's a PVC fitting that goes over a
2" stainless schedule 40 support pipe that is loose fitting. I want
to machine one with a sleeve bearing on a lathe and make it out of
plastic. However, I really don't have any experience machining
plastic, I've been looking at www.mscdirect.com under Raw
Materials/Plastic Material/Rods for 3" material. To keep costs under
control I'm looking at the following:

Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall
strength
of
these would be greatly appreciated.

-- Geoff

Machining Characteristics of Plastics
 

It's definately a blade balance issue, but I've carefully run through
the balancing instructions and I can't find any blade that's heavier
than the others. I'm sure that there are some harmonics that are
causing it, but I haven't been able to figure out how to balance it.

None of the PVC fittings that came with it provided what I would call a
snug fit. There was a good 1/16" clearance around the pipe, which
certainly is enough to allow vibration.

-- Geoff


"Doug Dotson" wrote in
:

What kind of speeds are producing this effect? My KISS doesn't
produce any significant vibration up to 30 kts or so. That is as fast
as I have run it. Have you checked the balance of the blades? A
slight unbalance in the blades might induce a vibration in the
mounting. I chose to use 2" SS tube rather than sched 40 pipe. The
PVC fitting is a snug fit. The KISS came with an assortment of
fittings to fit a number of different kinds of pipe. If the 2" tube
fits the KISS better than the sched 40 pipe, perhaps attaching a short
length of 2" tube to the top of the pipe for mounting would be a
simpler solution.

Doug
s/v Callista

"Geoffrey W. Schultz" wrote in message
. 16...
I have a KISS wind generator that develops vibration at certain wind
speeds. The problem is that there's a PVC fitting that goes over a
2" stainless schedule 40 support pipe that is loose fitting. I want
to machine one with a sleeve bearing on a lathe and make it out of
plastic. However, I really don't have any experience machining
plastic, I've been looking at www.mscdirect.com under Raw
Materials/Plastic Material/Rods for 3" material. To keep costs under
control I'm looking at the following:

Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall
strength
of
these would be greatly appreciated.

-- Geoff

Machining Characteristics of Plastics
 

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, 11 Nov 2003 15:23:37 -0500,
Glenn Ashmore wrote:
My bookmarks are so disorganized that I wish there was something like
google to search them. I have everything from thermodynamic formulas
for steam engines to how to make springs to the Forest Products Lab
encyclobedia of woods and timber production. From the Billboard top 50
archive to NPR's essential library of classical music.

What was that old Heinlein quote? "A man should be able to change a
diaper, plan an invasion, butcher a hog, sail a ship, design a building,
write a sonnet, balance accounts, build a wall, set a bone, comfort the
dying, take orders, give orders, cooperate, act alone, solve equations,
analyse a problem, pitch manure, program a computer, cook a tasty meal,
fight efficiently and die gallantly. Specialisation is for insects."

I may not be able to do them all but I can find out how somewhere in my
bookmarks. :-)

Jim Woodward wrote:



Try Mozilla, you can search the bookmarks, in the manage bookmarks mode.
Search on URL, name, descriptin, keywords. You can even save the search
terms as a bookmark. :) This makes dealing with hundreds of bookmarks
(no, that's not a typo...) possible for me.

Of course, you can also export them as tags, and grep through that, but
that's a little more work.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.3 (GNU/Linux)

iD8DBQE/sguMd90bcYOAWPYRAn5BAJ9rc3emjrltzh4f0d2CIhFGDz0Elw CdE70i
lNpkASEtZFMQISAm2k6l6Qw=
=BadB
-----END PGP SIGNATURE-----

--
Jim Richardson http://www.eskimo.com/~warlock
Orwell and Roddenberry weren't just writers, they were prophets.

Machining Characteristics of Plastics
 

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, 11 Nov 2003 15:23:37 -0500,
Glenn Ashmore wrote:
My bookmarks are so disorganized that I wish there was something like
google to search them. I have everything from thermodynamic formulas
for steam engines to how to make springs to the Forest Products Lab
encyclobedia of woods and timber production. From the Billboard top 50
archive to NPR's essential library of classical music.

What was that old Heinlein quote? "A man should be able to change a
diaper, plan an invasion, butcher a hog, sail a ship, design a building,
write a sonnet, balance accounts, build a wall, set a bone, comfort the
dying, take orders, give orders, cooperate, act alone, solve equations,
analyse a problem, pitch manure, program a computer, cook a tasty meal,
fight efficiently and die gallantly. Specialisation is for insects."

I may not be able to do them all but I can find out how somewhere in my
bookmarks. :-)

Jim Woodward wrote:



Try Mozilla, you can search the bookmarks, in the manage bookmarks mode.
Search on URL, name, descriptin, keywords. You can even save the search
terms as a bookmark. :) This makes dealing with hundreds of bookmarks
(no, that's not a typo...) possible for me.

Of course, you can also export them as tags, and grep through that, but
that's a little more work.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.3 (GNU/Linux)

iD8DBQE/sguMd90bcYOAWPYRAn5BAJ9rc3emjrltzh4f0d2CIhFGDz0Elw CdE70i
lNpkASEtZFMQISAm2k6l6Qw=
=BadB
-----END PGP SIGNATURE-----

--
Jim Richardson http://www.eskimo.com/~warlock
Orwell and Roddenberry weren't just writers, they were prophets.

Machining Characteristics of Plastics
 

Use a high speed bit with a lot of rake,and hone the point to about .010"
radius.UHMW and nylon will machine like butter,and do fine.

Benny
S/V Panacea

Machining Characteristics of Plastics
 

Use a high speed bit with a lot of rake,and hone the point to about .010"
radius.UHMW and nylon will machine like butter,and do fine.

Benny
S/V Panacea

Machining Characteristics of Plastics
 

The 2" tubing gives is good fit and since it is polished to a high
finish, it swivels nice and smooth. I was originally going to use
sched 40 pipe but the guy at the stainless place (KATO Marine
in Annapolis) talked me out of it. Said sched 40 pipe was very
heavy and cost 3x what the tubing did. Also, the tubing is polished
to a high luster so it looks really nice. As I suggested earlier, it
might be good just to have a 6" piece of tube welded onto the
top of the pole. The instructions said that the PVC collar would
have to be slightly enlarged to accomodate the tube, but that
turned out not to be the case. 2 collars were provided, one fit
the tube perfectly.

Doug

"Geoffrey W. Schultz" wrote in message
.17...
It's definately a blade balance issue, but I've carefully run through
the balancing instructions and I can't find any blade that's heavier
than the others. I'm sure that there are some harmonics that are
causing it, but I haven't been able to figure out how to balance it.

None of the PVC fittings that came with it provided what I would call a
snug fit. There was a good 1/16" clearance around the pipe, which
certainly is enough to allow vibration.

-- Geoff


"Doug Dotson" wrote in
:

What kind of speeds are producing this effect? My KISS doesn't
produce any significant vibration up to 30 kts or so. That is as fast
as I have run it. Have you checked the balance of the blades? A
slight unbalance in the blades might induce a vibration in the
mounting. I chose to use 2" SS tube rather than sched 40 pipe. The
PVC fitting is a snug fit. The KISS came with an assortment of
fittings to fit a number of different kinds of pipe. If the 2" tube
fits the KISS better than the sched 40 pipe, perhaps attaching a short
length of 2" tube to the top of the pipe for mounting would be a
simpler solution.

Doug
s/v Callista

"Geoffrey W. Schultz" wrote in message
. 16...
I have a KISS wind generator that develops vibration at certain wind
speeds. The problem is that there's a PVC fitting that goes over a
2" stainless schedule 40 support pipe that is loose fitting. I want
to machine one with a sleeve bearing on a lathe and make it out of
plastic. However, I really don't have any experience machining
plastic, I've been looking at www.mscdirect.com under Raw
Materials/Plastic Material/Rods for 3" material. To keep costs under
control I'm looking at the following:

Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall
strength
of
these would be greatly appreciated.

-- Geoff

Machining Characteristics of Plastics
 

The 2" tubing gives is good fit and since it is polished to a high
finish, it swivels nice and smooth. I was originally going to use
sched 40 pipe but the guy at the stainless place (KATO Marine
in Annapolis) talked me out of it. Said sched 40 pipe was very
heavy and cost 3x what the tubing did. Also, the tubing is polished
to a high luster so it looks really nice. As I suggested earlier, it
might be good just to have a 6" piece of tube welded onto the
top of the pole. The instructions said that the PVC collar would
have to be slightly enlarged to accomodate the tube, but that
turned out not to be the case. 2 collars were provided, one fit
the tube perfectly.

Doug

"Geoffrey W. Schultz" wrote in message
.17...
It's definately a blade balance issue, but I've carefully run through
the balancing instructions and I can't find any blade that's heavier
than the others. I'm sure that there are some harmonics that are
causing it, but I haven't been able to figure out how to balance it.

None of the PVC fittings that came with it provided what I would call a
snug fit. There was a good 1/16" clearance around the pipe, which
certainly is enough to allow vibration.

-- Geoff


"Doug Dotson" wrote in
:

What kind of speeds are producing this effect? My KISS doesn't
produce any significant vibration up to 30 kts or so. That is as fast
as I have run it. Have you checked the balance of the blades? A
slight unbalance in the blades might induce a vibration in the
mounting. I chose to use 2" SS tube rather than sched 40 pipe. The
PVC fitting is a snug fit. The KISS came with an assortment of
fittings to fit a number of different kinds of pipe. If the 2" tube
fits the KISS better than the sched 40 pipe, perhaps attaching a short
length of 2" tube to the top of the pipe for mounting would be a
simpler solution.

Doug
s/v Callista

"Geoffrey W. Schultz" wrote in message
. 16...
I have a KISS wind generator that develops vibration at certain wind
speeds. The problem is that there's a PVC fitting that goes over a
2" stainless schedule 40 support pipe that is loose fitting. I want
to machine one with a sleeve bearing on a lathe and make it out of
plastic. However, I really don't have any experience machining
plastic, I've been looking at www.mscdirect.com under Raw
Materials/Plastic Material/Rods for 3" material. To keep costs under
control I'm looking at the following:

Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall
strength
of
these would be greatly appreciated.

-- Geoff

Machining Characteristics of Plastics
 

On Tue, 11 Nov 2003 14:45:26 GMT, "Geoffrey W. Schultz"
wrote:


Nylon
Acetal
UHMW
LDPE
HDPE

Comments on the machining qualities, UV resistance, and overall strength of
these would be greatly appreciated.

I have limited experience in the others but like Delrin (Acetal). It
is very durable, easy to work with (for an amateur like me), and is
easy to get a good finish on in a machine. It is also available in
versions with very good UV resistibility, much better than Nylon.

http://plastics.dupont.com/NASApp/my...0&locale=en_US

http://www.sdplastics.com/ultravioletresistance.html



/Marcus

--
Marcus AAkesson
Gothenburg Callsigns: SM6XFN & SB4779
Sweden
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