andrewskj

What is the best way to line up the holes so they are straight and the screws go right in to the control horns when installing on your control surfaces . Especially the three hole horns? It all looks so good until you try to line them and put the screws in then you find they really don't match up . Thanks in advance for any help you can share . Ken

Charlie P.

I use a pin vise to hold a small drill (1/32" or so) and drill the first hole. If that looks good I enlarge it (1/16 or so) and jab a wood toothpick into the horn, through the hole and into the backing plate. The next hole I again use the 1/32" bit and make sure it comes out into the corresponding hole in the backing plate, another toothpick and repeat (some have four holes). When threading in the machine screws it sometimes helps to use a fine file to round the nose just a bit. Put a nut on the screw first so after filing backing the nut off restores the threads clean.

Another trick is to get the first hole and then drill from both sides to meet in the middle on the rest (again with that 1/32" pilot hole). I always use finger drills rather than power drills for this.

da Rock

Drill the holes before attaching the surfaces and it's a bunch easier. With the flat profile ARF rudders and elevators, they can be drilled on a drill press. You can use the horn's holes for a template on some brands of horns.

Another trick you can do if you've got a belt sander is to sharpen the bolts to a point. The flat end often fights entering. A pointed end finds and enters.

MinnFlyer

My Feedback: (4)

I usually put the horn in place and drill one hole, put a screw through it to hold it in place and drill another, again adding a screw (if there is a third hole, repeat).

Now put the back plate in place and note if any screws do not align - and more importantly, if they do not align, in which direction they are off.

Now, remove the screw that is out of alignment, put the drill bit back in the hole and as it's spinning, angle the drill opposite the direction that it was off.

This, of course, will elongate the hole, but it is the clamping action of the two plates that does 99% of the holding, not the hole itself.

Finally, do not tighten one screw and then try to add the others. Get both or all three started first and tighten them a little bit each until they are snug.

Glacier Girl

My Feedback: (4)

Dang, unless it's a really thick control surface, I've always used my handy dandy trusty ice pick.
Hold the control horn where I want it, and either poke through the control surface or p rick( had to put a space in there, otherwise RCU thinks I'm using a naughty word and blanks it out) it so it leaves a mark.

Then I can use the Mark 8 eyeball to be sure the pick is straight and poke it through. If the material is thick and I don't need a bigger hole I just run the pick through enough to mark the opposite side of the control surface, then poke it from that side.

No torn covering and I've never split or torn up the wood inside. And no drilled through fingers. [X(]

Charlie P.

Oh - PS. Back the screws out and drip CA into the holes to strengthen them and then reinstall the horns after it has had plenty of time to set. Keeps the holes from wearing and helps stop the balsa from crushing.

niceguy1817

hi everyone i just bought a cherokee arf and i was drilling the holes on my control horns for my elevator when it moved and now a hole is where it shouldnt be does anyone have any advice on how i can fix this problem i heard if i mix epoxy and microbaloons it should fix it can anyone please help

Pylonracr

Yup, you can fill the holes with epoxu and microballoons. I asume the control surface is covered, so put a piece of scotch tape on one side and fill it up.

jester_s1

An easier way is to stick a toothpick into the hole with some wood glue and cut it off flush.

KW_Counter

I use Dubro Horn Brackets with a 4-40 bolt - link below.
I only have to drill one hole. I do this 'cause I got tired of
trying to line up 3 or 4.

Good Luck,
KW_Counter

http://www3.towerhobbies.com/cgi-bin...?&I=LXD947&P=7

Oberst

That's the way to go, but I tend to use what they give me in the kit or ARF because I want to save a little cash. I've been building ARF and built a couple of kits and been in this hobby a little over 10 years. I still have a little problem lining everything up a little when I finger drill into a funky angled control surface. Practice makes perfect I guess.



Pete

MinnFlyer

My Feedback: (4)

If the hole is just off a little, just enlarge it. It's the clamping action of the horn and the backplate that does 99% of the holding