Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.

In article , xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please.

IIRC, the navy has used both Lignum Vitae (oily enough by itself) and
hard maple vacuum impregnated with oil. Both will probably wear better
than plastics.

Delrin, umhw or acetal (which may be delrin again, off-brand) might all
work from the plastic end, I generally prefer the moly-filled versions.
Teflon is slippery, but a bit on the soft side.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

"Ecnerwal" wrote in
message
...
In article , xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts,
suggestions
for bearing materiel please.

IIRC, the navy has used both Lignum Vitae (oily enough by itself)
and
hard maple vacuum impregnated with oil. Both will probably wear
better
than plastics.

If you don't have a vacuum chamber, heating the wood in oil (or wax)
forces out the water and much of the air, and the liquid will be
sucked in as it cools.

jsw

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.

I've seen ceramic bearings advertised and wonder if they'd be good in
a watery scenario. Ball bearings would be much better than bushings.

--
Stay centered by accepting whatever you are doing.
This is the ultimate. -- Chuang-tzu

"xpzzzz" wrote in message
...
Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.


No answers to your questions, however something you may be interested
in.....

I saw some video of a pedal powered kayak thingo on TV the other night. It
had "push pedals" (left pedal went down / right came up sort of thing) and
flaps underneath rather than a rotary propeller. It seemed quite efficient
and worked very well.

I could not find any images online but I found this link which discusses
rotary v flap propellers.

http://wavewalk.com/blog/2010/10/11/...ishing-kayaks/

On Wed, 29 Aug 2012 05:55:46 -0700, Larry Jaques
wrote:

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.

I've seen ceramic bearings advertised and wonder if they'd be good in
a watery scenario. Ball bearings would be much better than bushings.

I've used ceramic bearings in hot corrosive service, but not
submerged. I think the difficulty in getting a complete seal and
particulates in the water would cause ball bearings to fail sooner and
more catastrophically than bushings.

Dad tried roller bearing pillow blocks on his rice field levee rollers
once(4500# concrete spool, mild steel axle). They failed in less than
a year. Big loads, lots of dirt, slow speed, side of the field
storage. The maple blocks we boiled in old oil usually lasted at
least a decade.

Pete Keillor

On Wed, 29 Aug 2012 08:17:01 -0500, Pete Keillor
wrote:

On Wed, 29 Aug 2012 05:55:46 -0700, Larry Jaques
wrote:

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.

I've seen ceramic bearings advertised and wonder if they'd be good in
a watery scenario. Ball bearings would be much better than bushings.

I've used ceramic bearings in hot corrosive service, but not
submerged. I think the difficulty in getting a complete seal and
particulates in the water would cause ball bearings to fail sooner and
more catastrophically than bushings.

Dad tried roller bearing pillow blocks on his rice field levee rollers
once(4500# concrete spool, mild steel axle). They failed in less than
a year. Big loads, lots of dirt, slow speed, side of the field
storage. The maple blocks we boiled in old oil usually lasted at
least a decade.

But would they have worked as well on a pedal-powered unit?
Anything you can do to reduce friction or inefficiencies on a
human-powered device is a real must.

--
Stay centered by accepting whatever you are doing.
This is the ultimate. -- Chuang-tzu

In article , xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please.


PV will be VERY low... on stainless, HDPE, UHMWPE, or acetal will all work
submerged. Nylon is a No-No, because it absorbs water, and will swell.

LLoyd

On Wed, 29 Aug 2012 06:36:25 -0700, Larry Jaques
wrote:

On Wed, 29 Aug 2012 08:17:01 -0500, Pete Keillor
wrote:

On Wed, 29 Aug 2012 05:55:46 -0700, Larry Jaques
wrote:

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.

I've seen ceramic bearings advertised and wonder if they'd be good in
a watery scenario. Ball bearings would be much better than bushings.

I've used ceramic bearings in hot corrosive service, but not
submerged. I think the difficulty in getting a complete seal and
particulates in the water would cause ball bearings to fail sooner and
more catastrophically than bushings.

Dad tried roller bearing pillow blocks on his rice field levee rollers
once(4500# concrete spool, mild steel axle). They failed in less than
a year. Big loads, lots of dirt, slow speed, side of the field
storage. The maple blocks we boiled in old oil usually lasted at
least a decade.

But would they have worked as well on a pedal-powered unit?
Anything you can do to reduce friction or inefficiencies on a
human-powered device is a real must.

Some of the plastics are pretty slick, especially in water. A low
friction ball bearing isn't so low friction when it fails, which is
what I think would happen. Ceramic ball bearings are pretty
expensive, too.

I don't know what type of pedal powered boat he's considering. The
old paddle wheel things are horribly inefficient anyway, but good
exercise. Due to the miter gears, I'd guess he's planning on using a
prop. You'd only need the plastic for an outboard bearing, but the
major drag on efficiency would be a shaft packing gland or seal,
followed by the miter gears themselves.

A prop for pedal power would probably be larger diameter and higher
pitch due to the low speed. If he could avoid the miter gears, it'd
help. Maybe a timing belt with a twist? and angle the shaft enough to
avoid a seal, although that introduces another source of inefficiency.

I don't know how good the pedal powered kayaks are. Where I use a
kayak fishing, I think they'd draw too much. A lot of it is very
skinny water.

Personally, I'd stick with paddles or oars.

"Pete Keillor" wrote in message
...

Some of the plastics are pretty slick, especially in water. A low
friction ball bearing isn't so low friction when it fails, which is
what I think would happen. Ceramic ball bearings are pretty
expensive, too.


FWIW, these are home-made stainless steel needle bearing wheels on a
hydraulic lift that lives in an area outdoors that floods every
spring:
https://picasaweb.google.com/KB1DAL/...44353392854802

It's made of stainless pipe, round stock and TIG welding rod, and
fitted loosely enough to tolerate mud.

You also need a prop thrust bearing unless you plan to misuse the
miter gears for it.

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.

I've used UHMW blocks just drilled for the stainless shaft for 25
years now in my apple water bin dump. No lube, never maintained. look
like they may wear out in another 25 years or so.

Karl

On Wed, 29 Aug 2012 06:36:25 -0700, Larry Jaques
wrote:


But would they have worked as well on a pedal-powered unit?
Anything you can do to reduce friction or inefficiencies on a
human-powered device is a real must.

The standard "cutless" bearing on a prop shaft is a hydrodynamic
bearing made of rubber. The bearing surface is a number of flat pads
with grooves between that draw a layer of water between the shaft and
bearing. They work fine with both bronze and stainless shafts.
http://www.deepblueyachtsupply.com/F...ringQuote.aspx

Re plastic ball bearings:
http://www.igus.com/wpck/default.asp...ring&C=US&L=en

Plastic ball bearings have been used on sailboat blocks for many
years. The first I remember seeing had Delrin balls and hard anodized
aluminum races.

If the shaft speeds are too low for a cutless bearing, I'd go to Igus'
website and go thru the selection procedure to pick the best material.
Igus has no minimum and is very reasonable for small orders.
http://www.igus.com/wpck/default.asp...7103&C=US&L=en

--
Ned Simmons

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.
Since you are pedaling the boat the best material will be Delrin AF.
Delrin AF is teflon filled and is very low friction. The next choice
would be UHMW or nylon. Nylon absorbs water so it is best to rough
machine, soak in water for a week, and then finish machine. Then keep
the bearings submerged or put the boat in the water a week before the
season starts. But I would strongly suggest Delrin AF because it
performs VERY WELL with water as a lubricant when running stainless
shafting.
Eric

"Ecnerwal" wrote in message
...
snip--

Delrin, umhw or acetal (which may be delrin again, off-brand) might all
work from the plastic end, I generally prefer the moly-filled versions.
Teflon is slippery, but a bit on the soft side.

In such a case, consider Delrin AF.

Harold

wrote in message
...
On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.
Since you are pedaling the boat the best material will be Delrin AF.
Delrin AF is teflon filled and is very low friction. The next choice
would be UHMW or nylon. Nylon absorbs water so it is best to rough
machine, soak in water for a week, and then finish machine. Then keep
the bearings submerged or put the boat in the water a week before the
season starts. But I would strongly suggest Delrin AF because it
performs VERY WELL with water as a lubricant when running stainless
shafting.
Eric


I see you beat me to it, Eric. Good advice.

Harold

xpzzzz wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.
I built a wet bearing for a pump in an etching machine entirely out of
Plexiglas. It worked very well, but was used for continuous rotation
with minimal side thrust. I'd think delrin, nylon or similar material
should work fine. W. M. Berg, SDP and such outfits have all sorts of
gears in plastic, but again, fairly small sizes and certainly not cheap.

Jon

Pete Keillor wrote:
On Wed, 29 Aug 2012 06:36:25 -0700, Larry Jaques
wrote:

On Wed, 29 Aug 2012 08:17:01 -0500, Pete Keillor
wrote:

On Wed, 29 Aug 2012 05:55:46 -0700, Larry Jaques
wrote:

On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.


Most pedal boats use Delrin for the bushings, usually they are 1-1.5"
wide They are set up so they don't run below the waterline as well.

http://www.recumbents.com/wisil/hpb/compact_drive.htm will give you
some drive ideas.

--
Steve W.

On Thu, 30 Aug 2012 08:17:07 GMT, "Harold & Susan Vordos"
wrote:


wrote in message
.. .
On Wed, 29 Aug 2012 10:50:09 +0000 (UTC), xpzzzz
wrote:

Thinking of making a pedal-powered boat, stainless shafts, suggestions
for bearing materiel please. And sources for suitable plastic mitre
gears in qty=2 pairs, smallparts has some but they may be too small.
Since you are pedaling the boat the best material will be Delrin AF.
Delrin AF is teflon filled and is very low friction. The next choice
would be UHMW or nylon. Nylon absorbs water so it is best to rough
machine, soak in water for a week, and then finish machine. Then keep
the bearings submerged or put the boat in the water a week before the
season starts. But I would strongly suggest Delrin AF because it
performs VERY WELL with water as a lubricant when running stainless
shafting.
Eric


I see you beat me to it, Eric. Good advice.

Harold
Thanks Harold. I get it right once in a while.
Eric

On Thursday, August 30, 2012 11:51:26 AM UTC-5, Jon Elson wrote:
xpzzzz wrote:



Thinking of making a pedal-powered boat, stainless shafts, suggestions

for bearing materiel please. And sources for suitable plastic mitre

gears in qty=2 pairs, smallparts has some but they may be too small.

I built a wet bearing for a pump in an etching machine entirely out of

Plexiglas. It worked very well, but was used for continuous rotation

with minimal side thrust. I'd think delrin, nylon or similar material

should work fine. W. M. Berg, SDP and such outfits have all sorts of

gears in plastic, but again, fairly small sizes and certainly not cheap.



Jon

McMaster has delrin bearings. Not very expensive either.

Polyacetal (delrin is one trade name) is OK for low load work, on a scale of performance friction/wear/compressive sterngth/thermal dimensional change

Maritex 1-50 is one of the top plain bush materials, it has high MoS2 content and graphite. Better than teflon which is a soft material.

Seeing as someone mentioned rubber, nitrile rubber has been used for hydrodynamic bearings but it's wear rates aren't that great when compared to modern composites. Wear only occurs in start up and run down when the bush is effectively running dry, hence ships that are deep water and don't stop the shaft see longer lives in bearings.

For pedal power a very simple cheap solution will be adequate, but...be very careful with the running clearance and how you fit the material. Running clearance needs to allow for dimensional change from moisture absorption as well as thermal swell, if you press fit you will reduce the bore size. What you really don't want is a bearing that under some circumstances gets tight. This has bee the benefit of many of the new composites as they can have very low thermal swell and moisture swell, at the same time as being hard and with low dry friction properties, but they're not cheap. They are used on things like submarine dive planes in the US now.