Proctor turnbuckles.
 

Just wondering if anyone know how much force they can take. I see them used all the time on flying wires that have to take some pulling. I have them on the pull pull for the ailerons on my 1/4 cub and have used them for years. Now, I'm thanking bout putting them on the rudder, but they are only 2/56 threads. Looking for some input from others that have used them. When I used them on the ailerons I applied thick ca to the thread and then warped the safety wire on them

RE: Proctor turnbuckles.
 

I can't say how much tension the 2/56 brass can take without looking it up in an engineering manual but it is in tension and not in sheer, that makes a considerable difference. Dubro makes some with 4/40 thread if you need larger. I would not CA the turnbuckle ever. Why not just use safety wiring and leave it at that? I should think CA will ruin it for any other use? I know one thing, I have lots of them on my SE5a:).

RE: Proctor turnbuckles.
 

Might be wrong, but I thought that Proctor turnbuckles used a special 1/16" thread? I know they use a 1/16" thread on thier smaller turnbuckles.
Gary

RE: Proctor turnbuckles.
 

Gary, they have/had a couple different sizes. I have some of each. The really small ones are for static display models only.. or so they told me and they no longer make them. I thought the thread size was 2/56 on the normal size ones.. but I could be mistaken?

RE: Proctor turnbuckles.
 

Bob, just looked in their book. Their #2 which is a size 14 through the #7 which is a size 28 all show a 2.0 mm thread diameter by 0.4mm pitch. So their #2 through #7 clevis use the same size ends. I was speaking to Gary about a month or so ago about turnbuckles and he told me they were a 1/16" thread. He also said they have to get the 1/16" taps and dies special made since 1/16" is not a "normal" size thread. I do not know why the book says "mm" threads and he told me 1/16"? I doubt that any of their threads are of the 2-56 variety.
Gary

RE: Proctor turnbuckles.
 

Gary, thanks. I remember gary at Proctor saying that they make the turnbuckles in-house with a special machine. Thanks for the additional info.. not sure what I'll do with it though lol!

RE: Proctor turnbuckles.
 

use thread lock a soldering iron will loosen it if any adjustment is needed
and proctor uses them for both flying wires and rudder pull pull on most of the planes i have seen

RE: Proctor turnbuckles.
 

Ran some numbers on a weak brass alloy, and #2-56 brass thread should hold at least 60 lb - you'd probably crush the rudder post if you put 60 lb per side on the pull pull... ;)

Cheers!

Jim

RE: Proctor turnbuckles.
 

I use CA to lock them with no problems. Comes off with a little heat, and it's instant, rather than loctite.

RE: Proctor turnbuckles.
 

Well I called Proctor up and had a little chat. They said they had never done a test of strength on the turnbuckles, but had used them a lot on 1/3 and 1/4 scale. For the threads he said they were 1/64.

RE: Proctor turnbuckles.
 

Cub Man, are sure sure he said 1/64"? I just happened to have a #1 turnbuckle and my calipers handy. The threads measured .057" which is a lot larger than 1/64" (.0312). I also checked a #3 turnbuckle and it measured at .0675, 1/16" is .0625. Maybe he was talking about the thread pitch.
Gary

RE: Proctor turnbuckles.
 

yes he was talking about the thread pitch.