Screws too short for ball link nuts?

[atomicplatypus]

There seems to be a lot of TREX450 flyers with DX7 radios so I suspect a lot of you must be having the following problem...

The JR DS285 servo horns which come with the DX7 are too thick for placing nuts onto your ball links. There just isn’t enough thread on the Align screws for any type of hold. I’ve been flying for a while without nuts but as things start to wear in I started looking around to see what was available. The added security of a nut to prevent ball links from popping out gives me some peace of mind.

I’ve found that the Heli-Max AXE CP screw set (HMXE7342) for $3.75 comes with an assortment of screw lengths just perfect for this application. Some are exactly the correct length while others are just a little bit longer. Your links will fit over the screw head without problem.

So if you can’t find the tiny screws required elsewhere then your local hobby shop should carry the AXE CP screw set. This saves you from countersinking the servo horns or grinding on the ball links.

Hope that helps!

HobbyHobby.com carries the set if you can’t find it elsewhere.
http://www.hobbyhobby.com/store/prod...oducts_id=1798

The two attached photos show a shorter and longer screw. The shorter screw is just shy of being flush with the nut. The longer, if there are no binding issues on your heli will give that extra security.

[mikelebron]

Originally Posted by atomicplatypus

There seems to be a lot of TREX450 flyers with DX7 radios so I suspect a lot of you must be having the following problem...

The JR DS285 servo horns which come with the DX7 are too thick for placing nuts onto your ball links. There just isn’t enough thread on the Align screws for any type of hold. I’ve been flying for a while without nuts but as things start to wear in I started looking around to see what was available. The added security of a nut to prevent ball links from popping out gives me some peace of mind.

I’ve found that the Heli-Max AXE CP screw set (HMXE7342) for $3.75 comes with an assortment of screw lengths just perfect for this application. Some are exactly the correct length while others are just a little bit longer. Your links will fit over the screw head without problem.

So if you can’t find the tiny screws required elsewhere then your local hobby shop should carry the AXE CP screw set. This saves you from countersinking the servo horns or grinding on the ball links.

Hope that helps!

HobbyHobby.com carries the set if you can’t find it elsewhere.
http://www.hobbyhobby.com/store/prod...oducts_id=1798

The two attached photos show a shorter and longer screw. The shorter screw is just shy of being flush with the nut. The longer, if there are no binding issues on your heli will give that extra security.

I had the same issue... Honestly, I was concnered, went to my LHS and they said screw the screw into the arm and get the nut on as tight as you can locktighting the screw... Did this and has worked fine... I even tried taking them apart at one point and really had to muscle the screw off. You just need enough meat to catch the screw.. The locktight will do the rest. Also keep in mind its the screw, screwing into the servo arm that is really keep it in tight.. not he nut. The nut is only to ensure it does not back out. I destroyed a whole set of servo arms as I drilled out the hole for the screws and then put the nut on.. thats a NONO. Drill it out JUST ENOUGH to where the threads catch.

I have been flying for about 4 weeks now.. no issues and nuts are still on tight.

[cbdane]

You can get the M2 screws that you need here. They typically cost about 1/25 the price of hobby screws. That simply means that for the price of 4 screws from the hobby shop, you get a box of 100.

www.mcmaster.com

Unfortunately, you can't post links to McMaster because of the way their site is designed. See attached screen dump below.

[BryMeister]

When I first built my V2 kit, I had the DS285 servos and I do not recall having such a problem. Maybe I used a different horn that you are, I don't know. I do remember that there was not that many threads left to attach the nut, but I got it on no problem. I was advised to use CA on the servo horn ball nuts vice thread-lock, FYI.

[franky92]

huh... I never used bolts:it is okay?

[atomicplatypus]

I found using the stock servo horns that I couldn’t get the nuts on at all. I found that they would JUST grip but I could pull it off with my fingers. They would probably fail if called upon to hold the ball during flight. I don’t trust CA that much given past experience so I opted for screws with more thread. I’ve used thread lock here as well. This is more for peace of mind than anything else, really.

[OhDonPiano]

I found the same as well with the 285s. I was not able to get even a single turn of the nut onto the ball link. I used a bit of CA to lock in the screws (they went on tight to begin with). I haven't had many flights, but I honestly can't imagine this being a point of mechanical failure.

[Montana_Reefer]

I just sanded the outer side of mine (the nut side) to catch a couple of threads. The thickness of the hi-tec's arms is 1.82mm the jr285's is 1.98mm. Dosent sound like much does it?

[350banshee]

Just like Montana_Reefer, I sanded a little off the backside of the arm to catch a few threads, then used locktite to secure the nut, 9 months now and no problems