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Pedal torque tube bushings? Question?

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darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Sat May 27, 2006 5:02 pm Post subject: Pedal torque tube bushings? Question?

I am assembling my rudder pedals on my series 7 and the torque tube bushings are bolted to the brackets and torqued to 35-40 in-lb.  This holds them tight against the brackets and does not allow for any movement with the pedals.  Obviously these bushings are not meant to rotate with the torque tube around the bolt but rather the torque tube rotates on the bushing.  My problem is that these bushings are significantly larger than the I.D. of my torque tube and will require significant sanding to allow for a smooth movement of the pedals.  Does anyone have some input on this?  My inclination is that I would rather have the tube and bushing rotate as one around the bolt but this won't allow for the proper torquing of the nut/bolt combination.  I don't see that as a huge problem as the load on the bolt is purely shear and not tension.  The nuts are nylon lock nuts so they should not back out.  Any thoughts?  Or what have others done.  Thanks,



Darin

smokey_bear_40220(at)yaho
Guest

Posted: Sat May 27, 2006 5:44 pm Post subject: Pedal torque tube bushings? Question?

Darin,



I had to remove all the paint out of the inside of the

tubes and deduce the bearings until it all fit.  I

spun them on a drill press and sanded them down.  The

first time I did it, the pedals would not return well

from spring tension alone.  You need to have it really

work smoothly to get it right.



After I worked everything to fit, I lubricated the

bearings too aid in smooth runner ops.  If you leave

it tight, the cables can go slack and possibly catch

on something or jump off track.



Also I had to shim the mounts, or they would bind as

torque was applied.  It seems the angle is just a tad

off so the mounts don't line up with the tubing.



It is worth it to make this operate well.  You just

have to keep at it.



Kurt S.  S-5/NSI tirbo



--- darinh <gerns25(at)netscape.net> wrote:



 	  Quote: 	
		   I am assembling my rudder pedals on my series 7 and

 the torque tube bushings are bolted to the brackets

 and torqued to 35-40 in-lb.  This holds them tight

 against the brackets and does not allow for any

 movement with the pedals.  Obviously these bushings

 are not meant to rotate with the torque tube around

 the bolt but rather the torque tube rotates on the

 bushing.  My problem is that these bushings are

 significantly larger than the I.D. of my torque tube

 and will require significant sanding to allow for a

 smooth movement of the pedals.  Does anyone have

 some input on this?  My inclination is that I would

 rather have the tube and bushing rotate as one

 around the bolt but this won't allow for the proper

 torquing of the nut/bolt combination.  I don't see

 that as a huge problem as the load on the bolt is

 purely shear and not tension.  The nuts are nylon

 lock nuts so they should not back out.  Any

 thoughts?  Or what have others done.  Thanks,

 

 Darin


	


__________________________________________________

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Sat May 27, 2006 6:53 pm Post subject: Re: Pedal torque tube bushings? Question?

Kurt,



Do you see anything wrong with having the bushing and torque tube rotate as one around the bolt as with a typical bolt/bearing combination?  This is the way I have it now and it is as smooth as silk with not side to side play or slop.  As mentioned, the bolts are only in shear and therefore the full tension strength of the bolt or nut is not needed as long as the nut does not come loose.  Being that they are nylon lock nuts, this won't be a problem.  I figure the wear of the bearing from the torque tube rotating around it would be more than that of the bolt because of the much larger contact area.  The bolt/bearing fit is much more precise and therefore much smoother.  Do you see anything wrong with this approach.  Maybe it would be best to install an AN4-11 bolt and castle nut with cotter pin, that way I would be assured that it would not come loose.  What do you think?



Darin

smokey_bear_40220(at)yaho
Guest

Posted: Sat May 27, 2006 8:56 pm Post subject: Pedal torque tube bushings? Question?

Hi Darin,



I forgot, but I think that the bolt is not threaded

under the bearing, correct?  It is a smooth contact? 

If not, you certainly would get a lot of wear.



Actually the pressure is spread out more on the

bearing to tube contact than the bearing to bolt

contact.  It should wear longer as planned.  Remember

that you can put up to 300 lbs of force on the pedals

in a panic and a pretty good amount in nornmal

rudder/brake usage.  The bolt hole in the bearing

might elongate under use if it rotates, but the tube

to bearing hole shouldn't.



I think it is definately better to use a castleated

nut and cotterpin on any rotating parts.  If you stick

with the bearing rotating on the bolt, you need the

castle nut/pin.



I got tired of trying to make this go together right

at first, but had to go back and fix it later when my

plane was done.  It is best to do it right at the

start.  As I said, you can put the bearing-bolt

assembly in a drill and file or sand it down while

spinning.  Try to keep it even and not tapered or

rounded.  After a bit it does go pretty fast and you

will like the results better.  Don't take too much off

though.



You always have a few "I-should-haves" when your plane

is done.  The fewer the better and none should be

after an accident.  In my case, I should have put

blind nuts under the fuselage so that the peddal

assembly can be removed and replaced entirely from

above.  As it is planned, you could be required to

remove the engine and firewall to get at the nuts.



Kurt S.



--- darinh <gerns25(at)netscape.net> wrote:



 	  Quote: 	
		   Kurt,

 

 Do you see anything wrong with having the bushing

 and torque tube rotate as one around the bolt as

 with a typical bolt/bearing combination?  This is

 the way I have it now and it is as smooth as silk

 with not side to side play or slop.  As mentioned,

 the bolts are only in shear and therefore the full

 tension strength of the bolt or nut is not needed as

 long as the nut does not come loose.  Being that

 they are nylon lock nuts, this won't be a problem. 

 I figure the wear of the bearing from the torque

 tube rotating around it would be more than that of

 the bolt because of the much larger contact area. 

 The bolt/bearing fit is much more precise and

 therefore much smoother.  Do you see anything wrong

 with this approach.  Maybe it would be best to

 install an AN4-11 bolt and castle nut with cotter

 pin, that way I would be assured that it would not

 come loose.  What do you think?

 

 Darin


	


__________________________________________________

steade(at)btinternet.com
Guest

Posted: Sun May 28, 2006 1:12 am Post subject: Pedal torque tube bushings? Question?

Darin



This is a common problem. Most people I know reduce the bushing =

diameter. Also you may have to shim the brackets where they bolt to the =

fuselage to make sure they are square to the pedal tubes. I don't think =

it is a good idea to allow rotation on the bolt.



Regards



David

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Sun May 28, 2006 6:16 am Post subject: Re: Pedal torque tube bushings? Question?

Ok, thanks for the remarks.  I definately don't want the "I should have" scenario so I will go with the application as outlined in the manual.  I have already removed a bit of bushing by sanding in a press so a little more shouldn't be a problem.  It is that alignment thing that I don't want to deal with but...



Thanks guys,



Darin

smokey_bear_40220(at)yaho
Guest

Posted: Sun May 28, 2006 7:36 am Post subject: Pedal torque tube bushings? Question?

darin,



I agree with David that shimming will fix the

alignment problem.  I shimmed the pedals and had to

shim the stick controls too in order to reduce bearing

binding.



You won't later regret smooth controls that you are

confident in.  



Kurt S.



--- David Steade <steade(at)btinternet.com> wrote:



 	  Quote: 	
		   Darin

 

 This is a common problem. Most people I know reduce

 the bushing =

 diameter. Also you may have to shim the brackets

 where they bolt to the =

 fuselage to make sure they are square to the pedal

 tubes. I don't think =

 it is a good idea to allow rotation on the bolt.

 

 Regards

 

 David


	


__________________________________________________

bnn(at)nethere.com
Guest

Posted: Sun May 28, 2006 11:20 am Post subject: Pedal torque tube bushings? Question?

At 07:53 PM 5/27/2006, you wrote:

 	  Quote: 	
		  Do you see anything wrong with having the bushing and torque tube rotate 

as one around the bolt as with a typical bolt/bearing combination?


	


         I don't like it, as the bearing area and therefore wear area is 

much smaller. Your bushings will wear much faster. Now if you really wanted 

to do it right, you could replace the bushings with sealed ball bearings. 

I'll bet you could find some that fit.

         You must also use a castle/cotter combo on anything that rotates 

directly on the bolt. (AC 43-13)

 	  Quote: 	
		  


	


Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

smokey_bear_40220(at)yaho
Guest

Posted: Sun May 28, 2006 12:06 pm Post subject: Pedal torque tube bushings? Question?

Guy is right!  Ball bearings are the way to go for top

rated controls.  Just depends upon how good you want

it.



Makes me think of John King's planes, Rick's Soob

engine (I should have bought), or a new KitFox company

in the right hands....  I am convinced there are

people here that could team up and make a flying

carpet company.  "DreamFox"?  Guy's controls.  Don S.

for safety, Torgier for research... we got them all

here.



I can dream too..... 



I wonder what the Extra 300 uses?  Unless you have

felt the controls on one of those, you don't know what

you are missing.  Talk about smmmoooooth....  Probably

ball bearings throughout.  Best I have ever felt

anyway.



Kurt S.



--- Guy Buchanan <bnn(at)nethere.com> wrote:



 	  Quote: 	
		   .............  Now if you really wanted 

 to do it right, you could replace the bushings with

 sealed ball bearings.

 
	


 	  Quote: 	
		   I'll bet you could find some that fit.

 You must also use a castle/cotter combo on

 anything that rotates directly on the bolt. (AC

43-13)
	


 	  Quote: 	
		   >

 Guy Buchanan

 K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob

 Ducar.


	


__________________________________________________

ddsyverson(at)comcast.net
Guest

Posted: Sun May 28, 2006 1:58 pm Post subject: Pedal torque tube bushings? Question?

Darin,



I also have a model 7 and found out that everything worked out perfectly on 

the rudder pedal torque tube mounting doing a couple things:



1) Inside the torque tube ends to the lenght of the bushing insertion, make 

sure that there is no paint, lumps of any other kind present and that the 

inside of the torque tube ends are perfectly round and smooth - I finished 

off this task by putting a folded strip of 240 grit wet/dry sandpaper onto a 

split dowel (cut lenghtwise with a bandsaw about an inch) then used a drill 

on the dowel to polish up the inside of the torque tubes.



2) Thereafter, chuck the bushings in a drill press and work them down till 

they fit the torque tubes nicely. Be sure that the bushing is worked down 

evenly (no grooves or taper) - backing up a piece of fine sandpaper with a 

flat stick works, also touching up with a straight cut file with the bushing 

spinning works too. An inside/outside micrometer will help a person gauge how 

much material is being removed so you don't go too far.



In 1) & 2) above - finish off with 400 grit wet/dry sandpaper - the finer 

finish leaves much less friction.



End result - very smooth operation, close tolerances and no binding. I think 

lubrication is a good idea, but primarily for corrosion prevention on the 

inside of the torque tube.  



The bushing is not supposed to rotate on the bolt, the torque tubes should 

rotate on the bushing.



Dave S

St Paul, MN



On Saturday 27 May 2006 8:02 pm, darinh wrote:

 	  Quote: 	
		   



 I am assembling my rudder pedals on my series 7 and the torque tube

 bushings are bolted to the brackets and torqued to 35-40 in-lb.  This holds

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Sun May 28, 2006 4:17 pm Post subject: Re: Pedal torque tube bushings? Question?

Well, I reworked the pedals and now they are smooth and rotate on the bushing.  I used a similar method to what Dave S. described.  The controls are smooth but the ball bearings would be a great addition.  I think I may look into this option as I have a bearing supply house close.  A nice press fit on the bearings with some loctite and those pedals would be like butter!  Anyway, thanks for the input...It is great to know when I have a question I can have it answered right here from someone (a bunch of people in most cases) who has "been there, done that".  Now on to the next item of business, the rudder and then wings.



Darin

lcfitt(at)sbcglobal.net
Guest

Posted: Sun May 28, 2006 4:18 pm Post subject: Pedal torque tube bushings? Question?

I put ball and needle bearings in my camera mount system replacing Delrin 

and got a significant improvement in smoothness.  One thing I noticed is 

that with the delrin bushings, if the systam was left in a set position for 

any time, any lubrication was squeezed out of the pivot and the first 

movement was a pop or jerk then smooth movement as the lube took over.



Actually the reason for the post is the bearing source I found - good 

service, any quantity and they deal with people like us - hobbyists.



http://www.bocabearings.com/



Lowell



---

smokey_bear_40220(at)yaho
Guest

Posted: Mon May 29, 2006 10:11 am Post subject: Pedal torque tube bushings? Question?

Based upon what someone posted a while back on the

list, I started using chain lube last year for these

type applications.  It flows in very well, but forms

kind of a wax coating that seems to stay put.  Also it

does not soak in dirt like oils do.



I was once told that oils attack these bearings

anyway, but haven`t tested that.



I have also used silicon spray, and it works, but only

for a short period.



In some places I use silicon grease at that is a bit

better, but holds dirt.



Anyone have any better lubricants to use?



Kurt S.



--- Lowell Fitt <lcfitt(at)sbcglobal.net> wrote:



 	  Quote: 	
		   I put ball and needle bearings in my camera mount

 system replacing Delrin 

 and got a significant improvement in smoothness. 

 One thing I noticed is 

 that with the delrin bushings, if the systam was

 left in a set position for 

 any time, any lubrication was squeezed out of the

 pivot and the first 

 movement was a pop or jerk then smooth movement as

 the lube took over.

 

 Actually the reason for the post is the bearing

 source I found - good 

 service, any quantity and they deal with people like

 us - hobbyists.

 

 http://www.bocabearings.com/

 

 Lowell


	


__________________________________________________

skyflyte(at)comcast.net
Guest

Posted: Tue May 30, 2006 12:48 pm Post subject: Pedal torque tube bushings? Question?

Good choice Darin.  Your previous description of the bearings rotation on a bolt and nyloc nut were not the right way to go.  Any bolt subject to rotation should be secured with a castle nut and cotter pin, something which would be difficult to inspect on the rudder peddle bearings.

   Mike



-------------- Original message -------------- 

From: "darinh" <gerns25(at)netscape.net> 



 	  Quote: 	
		   

 

 Well, I reworked the pedals and now they are smooth and rotate on the bushing. 

 I used a similar method to what Dave S. described. The controls are smooth but 

 the ball bearings would be a great addition. I think I may look into this 

 option as I have a bearing supply house close. A nice press fit on the bearings 

 with some loctite and those pedals would be like butter! Anyway, thanks for the 

 input...It is great to know when I have a question I can have it answered right 

 here from someone (a bunch of people in most cases) who has "been there, done 

 that". Now on to the next item of business, the rudder and then wings. 

 

 Darin 

 

 

 

 

 Read this topic online here: 

 

 http://forums.matronics.com/viewtopic.php?p=37037#37037 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

<html><body>
	


<DIV>Good choice Darin.&nbsp; Your previous description of the bearings rotation on a bolt and nyloc nut were not the right way to go.&nbsp; Any bolt subject to rotation should be secured with a castle nut and cotter pin, something which would be difficult to inspect on the rudder peddle bearings.</DIV>

<DIV>&nbsp;&nbsp; Mike</DIV>

<DIV>&nbsp;</DIV>

<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">-------------- Original message -------------- <BR>From: "darinh" &lt;gerns25(at)netscape.net&gt; <BR><BR>&gt; --&gt; Kitfox-List message posted by: "darinh" <GERNS25(at)NETSCAPE.NET><BR>&gt; <BR>&gt; Well, I reworked the pedals and now they are smooth and rotate on the bushing. <BR>&gt; I used a similar method to what Dave S. described. The controls are smooth but <BR>&gt; the ball bearings would be a great addition. I think I may look into this <BR>&gt; option as I have a bearing supply house close. A nice press fit on the bearings <BR>&gt; with some loctite and those pedals would be like butter! Anyway, thanks for the <BR>&gt; input...It is great to know when I have a question I can have it answered right <BR>&gt; here from someone (a bunch of people in most cases) who has "been there, done <BR>&gt; that". Now on to the next item of business, the rudder and then wings. <BR>&gt; <BR>&gt; Darin

  <BR>&

 List C

bnn(at)nethere.com
Guest

Posted: Fri Jun 02, 2006 7:23 pm Post subject: Pedal torque tube bushings? Question?

At 11:09 AM 5/29/2006, you wrote:

 	  Quote: 	
		  Anyone have any better lubricants to use?


	


Well I don't know if it's better, but I've long used Tri-Flon for anything 

plastic. I used it in my sailing days exclusively. There's a new company, 

McLube, that also has a lot of lubricants suitable for plastics and other 

marine applications.



http://www.888teammclube.com/frames/sailkote/index.html

Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

ruebd(at)skymail.csus.edu
Guest

Posted: Mon Jun 05, 2006 7:32 am Post subject: Pedal torque tube bushings? Question?

Any good quality silicon spray lube, of which there are many now would

be better than any petroleum based lube, and they are easy to use.  Pick

one that has some body to it, rather than a thin one, you can test this

by spraying it on your finger and evaluating it.  I found that 3-In One

has a good one these days.  STP used to offer one in a smaller spray

can, which had good body (staying where you want it for longer periods).

The smaller can was great because that makes it easier to get the stuff

where you want it to go.  



Duane Rueb



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