centex_buggier - 18-12-2008 at 06:40 PM
I have gone through several harness spreader bar pulleys that are phenolic and I want to make a new roller out of aluminum that hopefully will last
longer.
A friend of mine modeled one up in solid works and I am going to send it out for quotes. Anyone have experience with this that can comment on the
design? It will be a shoulder bolt with two oilite bushings and locked to the spreader bar with a locknut.
speleopower - 19-12-2008 at 07:57 PM
Concept Air used to make a metal roller years ago. If you can get them made for reasonable cost I would be interested in one for my spreader bar.
Scott
centex_buggier - 19-12-2008 at 08:22 PM
I'll send it out for quotes and see what the setup charges are vs the lathing charges. If they can do it without a jig, it might not be bad.
Here's another image, do you think it's deep enough?
Steve.
NPWfever - 19-12-2008 at 08:28 PM
I may consider making it the same width, but a little shorter, so the "cup" is more pronounced so the strop doesnt come out
speleopower - 19-12-2008 at 08:35 PM
Get a standard Dakine roller from a Dakine spreader bar and that would be the perfect shape. Has worked for me for years
Scott
centex_buggier - 19-12-2008 at 09:25 PM
He actually started with the standard Dakine pulley and rounded the rims a little more. I had him make it symetrical so that the top and bottom rims
are the same diameter. The Dakine one has a larger top rim than the bottom for some reason. I figured it would be less likely to slip off the bottom
if it was larger. It's the same width as the Dakine even though it might not look like it.
I could have him make the rims a larger diameter or decrease the width.
The mounting system will be far more robust than the Dakine too.
krumly - 20-12-2008 at 08:11 PM
I'd approach using oilite bushings in aluminum with caution. Bronze and aluminum are generally not a good mix due to galvanic corrosion, especially
around salt water. Aluminum and stainless are acceptable. I'd use some lanocote or other anti-seize at a minimum where the metals touch each other.
krumly
WELDNGOD - 21-12-2008 at 06:22 AM
ditto, what krumly said.You'll be makin a battery ,at the alloys expense.I have to repair all kinds of thing that get EATEN by electrolysis .Even
with anodes .
I wonder if you could find needle bearings for it ,so it will have next to no rolling resistance.
I pondered this very same thing, then realized that I need a QR. And sometimes you get snatched so hard you physically can't unhook. So I made the
$115 Q.R., instead. Just somethin to think about 
acampbell - 21-12-2008 at 06:32 AM
Have you tried the Peter Lynn pulley spreader bar? Nice big pulley with roller bearings. I'd be suprised if you wore one out in a hurry.
centex_buggier - 21-12-2008 at 07:50 PM
The guy that came up with the design is aware of the incompatibility of dissimilar metals and said he chose 6061 Aluminum alloy that should not have a
problem with the bronze bushing around salt water. Though I did say I would be using it to buggy on the beach, I'll make sure he understands that we
want to use it immersed in salt water too. I'll talk to him about it again.
I haven't used the Peter Lynn pulley spreader, but it will be a candidate if this doesn't work out.
centex_buggier - 22-12-2008 at 09:25 AM
The bronze oilite bushings are seated in the pulley and the bearing surface is between the bushings and the stainless sholder bolt. The aluminum to
bronze interface is not designed to move.
Steve.
WELDNGOD - 22-12-2008 at 01:44 PM
I just replaced 4 flanges for the Navy, that were 6061. They were eaten almost in two by electrolysis. Heat treatment doesn't mean corrosion proof.
You can Anodize aluminum for protection. And that is as good as it gets.
