The Murphy Builders Site

I sanded off the paint and still had to sand the delrin blocks as well.
I don't believe the movement will wear looser in service but the Crown
brand silicone spray may help a little. Some of us also reinforced the
bottom of the horizontal bulkhead with a piece of stringer or angle left
to right. That is to keep the bulkhead from flexing down which may cause
some binding on the CC-68 delrin bearings when the rudder cables are
tensioned.

Ken

Joel Jacobs wrote:

Hi,
I've been working on the elevator controls where I'm mounting the
CC-68 in the RP-13 bearing blocks on the aft horizontal bulkhead. The
bearing blocks are a really tight fit. So, do I just enlarge the
holes in the bearings or should I start by removing the paint on the
CC-68 where it goes into the bearing. Does the paint wear off anyway?
I guess what I want to avoid is enlarging the bearing for a good fit
and then having the paint wear off and making the fit to loose. I'll
be having the same issue with the rudder pedals.
Thanks much,
Joel

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On my Moose I scraped away the excess material until I had smooth movement.
I did this for both rudder tubes about 7/8" and elevator torque tubes about
2.0" diameter's. I did remove the paint from the steel tubes and polished
them with very very very fine emery cloth.
I used a single edge raiser blade to remove material where it was a bit too
thick, I feel that sanding would leave a rough surface, I wanted a "window
glass smooth surface". This was the same procedure my grandfather used back
in the days of early automobile engine repairs when it was necessary to pour
a Babbitt bearing then scrape away the excess material to have a proper oil
clearance on a crankshaft.

By doing it this way I did not have any fine slivers of delrin to cause
interference, or make a change in the friction at these bearings.

My manual insists NO LUBRICATION on the delrin

Dick Wampach SR-108 N331RW



-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Saturday, October 24, 2009 7:12 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Derlin bearing block fit


I sanded off the paint and still had to sand the delrin blocks as well.
I don't believe the movement will wear looser in service but the Crown
brand silicone spray may help a little. Some of us also reinforced the
bottom of the horizontal bulkhead with a piece of stringer or angle left
to right. That is to keep the bulkhead from flexing down which may cause
some binding on the CC-68 delrin bearings when the rudder cables are
tensioned.

Ken

Joel Jacobs wrote:

Hi,
I've been working on the elevator controls where I'm mounting the
CC-68 in the RP-13 bearing blocks on the aft horizontal bulkhead. The
bearing blocks are a really tight fit. So, do I just enlarge the
holes in the bearings or should I start by removing the paint on the
CC-68 where it goes into the bearing. Does the paint wear off anyway?
I guess what I want to avoid is enlarging the bearing for a good fit
and then having the paint wear off and making the fit to loose. I'll
be having the same issue with the rudder pedals. Thanks much,
Joel

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I could never get the fit I wanted with the delrin bearings scrapped them
and made new ones out of aluminum after fitting sent away had coated with
teflon to make a lifetime slippery surface. Made a tighter fit also when
mounting to the floor.. Dale N269DF SR-033




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I used a rotary file in the drill press and took a few passes around the circumference of each block. worked great.

Date: Sat, 24 Oct 2009 22:12:07 -0400
From: klehman@albedo.net
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Derlin bearing block fit

I sanded off the paint and still had to sand the delrin blocks as well.
I don't believe the movement will wear looser in service but the Crown
brand silicone spray may help a little. Some of us also reinforced the
bottom of the horizontal bulkhead with a piece of stringer or angle left
to right. That is to keep the bulkhead from flexing down which may cause
some binding on the CC-68 delrin bearings when the rudder cables are
tensioned.

Ken

Joel Jacobs wrote:

Hi,
I've been working on the elevator controls where I'm mounting the
CC-68 in the RP-13 bearing blocks on the aft horizontal bulkhead. The
bearing blocks are a really tight fit. So, do I just enlarge the
holes in the bearings or should I start by removing the paint on the
CC-68 where it goes into the bearing. Does the paint wear off anyway?
I guess what I want to avoid is enlarging the bearing for a good fit
and then having the paint wear off and making the fit to loose. I'll
be having the same issue with the rudder pedals.
Thanks much,
Joel

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_________________________________________________________________
Windows 7: Simplify your PC. Learn more.
http://www.microsoft.com/Windows/window ... en1:102009



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Wow Dale, sounds like you took care of that problem for good! I can
see why you did that, after getting mine just right I bolted them down
and the material deformed so much it got real draggy. If I tighten the
bolts just till the slop is gone and maybe just a tad more then it moves
just fine. I'd like to have the bolts tighter but I don't see how with
the delrin blocks.
Joel

Dale Fultz wrote:

I could never get the fit I wanted with the delrin bearings scrapped them
and made new ones out of aluminum after fitting sent away had coated with
teflon to make a lifetime slippery surface. Made a tighter fit also when
mounting to the floor.. Dale N269DF SR-033




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