Avoid Dubro 4-40 threaded rod
11-28-2011, 03:46 PM
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Avoid Dubro 4-40 threaded rod
While installing the linkages on a new plane I am working on, I threaded the end of a Dubro 4-40 rod into one of my clevises and it seemed to have a very loose fit. I tried it on several other clevises and ball links with the same result. In fact I was able to pull the rod out of one of the clevises.
Next I tested the clevises and ball links with a 4-40 socket head cap screw and found that the fit was quite tight.
Using a digital caliper, I measured the diameter across the threads for the cap screw and the Dubro rod. The cap screw measured 0.109" and the threaded rod measured 0.100".
Use the threaded rod at your own risk.
Al
Next I tested the clevises and ball links with a 4-40 socket head cap screw and found that the fit was quite tight.
Using a digital caliper, I measured the diameter across the threads for the cap screw and the Dubro rod. The cap screw measured 0.109" and the threaded rod measured 0.100".
Use the threaded rod at your own risk.
Al
11-29-2011, 10:29 AM
#3
RE: Avoid Dubro 4-40 threaded rod
a lot of the hardware supplied with most giant scale planes is larger than 4-40..... for example the ball links will barely thread on to a 440 rod, and wont hold on tight
11-29-2011, 12:28 PM
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RE: Avoid Dubro 4-40 threaded rod
I'm using after-market Dubro ball links and clevises. I suspect that the threaded rods would work if I used them on virgin ball links and clevises. I like to run a tap into the fitting beforehand instead of using the rod to tap the thread.
11-29-2011, 01:37 PM
#5
RE: Avoid Dubro 4-40 threaded rod
ORIGINAL: azalner
While installing the linkages on a new plane I am working on, I threaded the end of a Dubro 4-40 rod into one of my clevises and it seemed to have a very loose fit. I tried it on several other clevises and ball links with the same result. In fact I was able to pull the rod out of one of the clevises.
Next I tested the clevises and ball links with a 4-40 socket head cap screw and found that the fit was quite tight.
Using a digital caliper, I measured the diameter across the threads for the cap screw and the Dubro rod. The cap screw measured 0.109" and the threaded rod measured 0.100".
Use the threaded rod at your own risk.
Al
While installing the linkages on a new plane I am working on, I threaded the end of a Dubro 4-40 rod into one of my clevises and it seemed to have a very loose fit. I tried it on several other clevises and ball links with the same result. In fact I was able to pull the rod out of one of the clevises.
Next I tested the clevises and ball links with a 4-40 socket head cap screw and found that the fit was quite tight.
Using a digital caliper, I measured the diameter across the threads for the cap screw and the Dubro rod. The cap screw measured 0.109" and the threaded rod measured 0.100".
Use the threaded rod at your own risk.
Al
11-29-2011, 03:11 PM
#7
Senior Member
RE: Avoid Dubro 4-40 threaded rod
I have at least half a dozen sticks here and all are up to spec. As mentioned earlier it COULD be a batch not up to spec or it could also be that the LHS made a mistake and put metric stuff in the 4-40 location/tube. Most of mine were bought in the last couple of month but not less a month ago.
