Belcrank with brass bushing

[Fred Quedenfeld jr]

I saw a picture of a Sig belcrank with brass bushings where the lines go through
Anyone know where I could buy the bushings?
or the whole belcrank
I am not ready for the $35 carbon ones from RSM
Fred Quedenfeld

[Donald Main]

Hi Fred,
  I use 1/16 brass tubing and put the lead out wire thru and bend and bind the leadouts

[Istvan Travnik]

Do not use metal-metal junction, if you want to get durable mechanism.
Simply buy a piece of 1/3 or 1/4 " thick textile bakelite ( Textolite or so on) plate, and saw & drill the proper shape & holes.
If want better try to find ZX100 plastic plate.

[MikeyPratt]

Hi Fred,
For the Sig 4” crank, use the 1/16” brass tubing from K & S for the lead-out cable's.  Drill out the bell-crank with a .040 drill bit and chamfer each side of the bell-crank (where the lead-out cables are attached).  Ive been doing it this for a long time and it always worked just fine with 1000’s of flights.  If needed, I can provide photos of doing it this way.

Mikey

 

[FLOYD CARTER]

The brass tubing idea does indeed result in metal to metal...brass against aluminum.  However, like many others, I have used this idea for years.  There is wear, but it would take a very long time and lots of flights to wear it out. I don't think any of my planes ever lasted 1000 flights, so I don't know.  Do you really expect 1000 flights?

[Istvan Travnik]

Dear Floyd  & friends,
Bellcrank is that part which won't be seen anymore after building (in good case)
So it needs blind trust, it must be really foolproof. 1000 flights looks to be many, but if you do not produce new plane in every 2-3-4 years, it can be collected normally.
And vibration is always present, mostly by IC engines. Proper plastics have better vibration damping features than brass/bronze etc.
These aspects look to be philosophical, but deserve to think over...
Istvan

[Air Ministry .]

Thats a Brodak 1/32 I.D. eyelet . I was looking for a SIG Ferrule . However you spell it .

Getting it just right with a centerpunch , & washer . Or a damp rag & pre tinned , with a quick dab .
Bit like the welding a fuel tank - Filled with water . As water dosnt explode very well , as its cool . Or Melt .
Or is it allready melted . 

[Phil Spillman]

Hi Fred, I used to bush all my Combat planes' Bell Cranks with lengths of 3/32 brass tubing as follows: Cut the brass to a length of about 3/16, use a nail set or some other tapered tool to flair out the first side of the work, of course you must drill out the Aluminum crank to receive the length of brass tubing first, then peen the flared tube over with a small ball peen hammer, turn the work over and repeat on the other side of the bellcrank. Run an appropriate drill through  the hole, add a length of schrink tight tubing on to the cable, run  the cable through the work and  wrap appropriately, shrink the tubing to adhere the whole job. I've got several bell cranks set up like this which are still performing after over 50 years! I used ball point pens for the pushrod areas of these old planes and once every thing is completed I added heavy bearing grease to all moving surfaces! Last a very long time!

Phil Spillman

[ericrule]

Fred:

RSM sells the SIG 3" nylon bell crank which we modify with the brass bushings (the picture you saw was likely one we modified) . In addition the 4" carbon fiber bell crank we sell costs only $19.99 not $35.00.