How to make perfect hinge slots

[Mike Griffin]

This is nothing new and many people have been doing this for years but for the sake of someone new to the forums, I thought I would post some pictures of how I create hinge slots for stabilizers, elevators and wing flaps.

If I am building a plane with a 1/4" solid sheet stab and elevator this is what I do. I start by taking a piece of 1/32nd balsa and cutting the hinge slots as per the position on the plan.  I then cut the the shape of the stab twice out of a 1/8th thick sheet of balsa.  Take one cutout of the stab and put some glue on it (I use Elmer's white glue and you can see how I apply it)and place the piece of 1/32nd with 1/2 of the hinge slots cut in it and place it on one of the 1/8th stab cutouts and weight it down till it drys.  When dry, place glue as shown in the picture on the 1/32 with the hinge cut outs and then place the remaining stab cutout on top and weight it down.  What you have done is create a sandwich with the 1/32 thick piece with the hinge cutouts in the middle. Do you Elevators the same way and make sure you measure accurately so that the slots created in the elevators with mate up with the slots you created in the stabilizer.  Put some glue in the slots of the stabilizer and insert 1/2 of the hinge in the slots and let it dry.  I use Elmers and let it cure overnight.  When dry,  put glue in the slot of the elevators and insert the remaining 1/2 of the hinge in the elevators.  If you have a split elevator remember you have to use a wire control horn to join them so they move together.  I use a piece of a cut up Playing card to get the glue back into the slot.

I hated the manual slot cutters so I bought a slot cutting machine and still hate that.  So I have switched to this method if I am going to use a nylon hinge.  I still build most of my models with Dacron cloth hinges that I buy from Aircraft Spruce but on rare occasions I will use Nylon pinned hinges.

Maybe this will help someone.

Mike

[MarcusCordeiro]

Cool Mike!
And you get them perfectly aligned.

Marcus

[Tim Wescott]

Some thoughts:

1: dang!  I need to try that!

2: I got a Slot Machine, and hated trying to make slots freehand.  So I strapped it down to a board.  Now I have a handful of blocks; I put a block on the board, and the surface to be slotted on the block, then slide it into the Slot Machine blade.  It's still not perfect, but it's a great deal better than what I was doing before.

3: If you run the grain of the 1/32" chordwise, then you'll have a surface made out of balsa plywood.  It'll probably be more warp resistance, and will certainly be less prone to splitting on less-than-perfect landings.

4: I've seen this done on TE stock, too: to make a 3/8" x 1/4" trailing edge with slots, use two 3/8" x 1/8" pieces.  Sand half-slots into each piece, glue, and voila -- slotted TE stock.

5: For making plywood out of balsa, I use Ambroid.  You need to do the whole double-glue thing, but the resulting assembly is strong, light, and smells slightly minty.

6: When I hinge with plastic hinges, I always use a long wire hinge pin.  I learned it from reading Paul Walker's build article in Flying Models.  While he uses it to get to the World's more easily, I use it because after severely damaging a plane, it's a lot easier to fix if I can pull the surfaces off just by sliding out a wire.

[Crist Rigotti]

Mike,
Excellent way to do hinges.
Check out my build log here.  Start with Reply #62.
https://stunthanger.com/smf/gettin-all-amp'ed-up!/2016-electric-stunter-build-log/msg431948/#msg431948

[Mike Griffin]

I'm interested in trying this but had a couple questions.

Why don't you glue the 3 sheets of balsa together with the hinges in place all at the same time?

Is there any problem using Zap Zpoxy to laminate everything?

Thanks,
Motorman

Walter there is no reason you cant.  I did it in this sequence for illustration purposes.  Yes I have used Zpoxy to laminate with.

Mike

[john e. holliday]

Motorman, some people like to finish parts before hinging them.   Many different ways of doing this part of a build.   Even though I like cloth hinges as they do two jobs at once I think on my newest kit it will get nylon hinges.   Thanks guys.

[Paul Walker]

Been building them like that for years. Straight and centered every time.