Cable thimble bushing

[barnstmr]

Re: Cable thimble bushing

Tom,
Now that you have put this in writing, I recall having seen this numerous times in the past. Great stuff. This is exactly the kind of tribal knowledge that comes from this kind of forum interaction. Thank you Tom for sharing this and documenting it for the younger fellas in the group. Perhaps we need a whole section devoted to little known facts of tribal knowledge.

[Guest]

Re: Cable thimble bushing

I'm about to make new aileron cables for my '46 BC-12D.
My old aileron cables had small, round, plastic inserts inside the thimbles.
When I ordered "Thimble Bushings" from Spruce, I got the little plastic things on the left which are clearly not the right part.
Any idea where I can get the round-bore thimble bushings? Or what they are called?

They were probabaly cut from electrical grade phenolic tubing that was a common technology for various bushings on these old planes.

Its very likley that the AN110 cable end bushing will not fit properly into the belcrank or where ever this goes.

Here is an example link for a source of said tubing => http://www.mcmaster.com/#phenolic-rods/=mvhf30

The have a 1/4" o.d. x 3/16" i.d.

I have seen this little bushing in the rudder cable too and frankly I can't imagine how its plasticity matters squat. It has a steel bolt thru the middle, its not moving much and it does provide anti-abrasion protection to the thimble.

Dave

[TimHicks]

Re: Cable thimble bushing

Here's an update on my An111 test.
Putting an AN111 inside of an AN100 thimble actually works remarkably well.
See the pictures attached. I had to spread the thimble open to get the bushing inside.
Then I had to squish the thimble as far back together as I could after the bushing was inside.
I could never get the thimble as far closed as it originally came. And I buggered up one of them by trying too hard (vises and hammers used in conjunction, a bit too heavy-handed).

But once I made the loop, it seemed good enough. The AN111 actually is free to rotate inside the thimble (I didn't intend this, I was trying to get the assembly as tight as possible), but there is no way that it will ever come out.

The loop with the AN111 bushing measured 0.765" at the widest part of the minor axis. So it would still pass through my fuselage fairlead loops at 0.810" ID. But that is a little bigger than my test loop without the AN111 which measured about 0.675".

And the thickness of the AN111 is just about exactly the same as the thickness of the thimble (in the direction of the bolt hole). So it seems that it would fit nicely.

But finally, my plan is just to make new straightwall bushings out of phenolic like several tribemembers have suggested. I ordered some 5/16" OD, 3/16" ID tube from McMaster like Dave suggested. (5/16" OD fits the thimble a bit better than 1/4" OD). That way I won't have to open and close all the thimbles. And it will be a touch lighter (I know, I know, flame me if you must).