Hi folks,

I have been flying for years but fairly new to building. This is the first stick build I have done where I need CA hinges. Could you direct me to a how to on getting a good cut into the balsa to instal the hinges? What is the best tool to insure a straight cut. The instructions seem to think doing it is a given...

Thanks for your help,

Just use an exacto blade. force it into the surface and wiggle it back and forth to make the cut. Do not remove any material. Just slit the wood. Make the slit wider than the width of the hinge.

Force the dry hinges into both surfaces. Completely assemble the part (e.g. rudder) to the airframe (e.g. Fin). Apply 4 or 5 drops of super-thin CA glue to the joint from both sides. The glue will wick up into the hinges and they will never come back out.

The only thing I'd add to that is that I put a pin through the center of the hinge, that way I can be sure that it is centered between the flight surface and the control surface. Otherwise, the CA hinge will slide in further on the side with the least resistance. Once I get all hinges installed and ready to glue, I remove the pins before gluing.

It helps to trim a little off each corner of each hinge...easier to install in the slots.
Check your local hobby shop for a Great Planes Precision Hinge Marking Tool # GPMGPMR 4005
or equivalent tool. $4 and worth every penny.
This assures a centered slot.

Originally Posted by FlyValue

Hi folks,

I have been flying for years but fairly new to building. This is the first stick build I have done where I need CA hinges. Could you direct me to a how to on getting a good cut into the balsa to instal the hinges? What is the best tool to insure a straight cut. The instructions seem to think doing it is a given...

Thanks for your help,

Here are the instructions that Great Planes provides in their kit assembly manuals.

IF.. I do say "if".. the surface is thick enough, so you can "center-cut" it.. you can use any straight-edge rule.. mark it.. slit it... otherwise the jig mentioned works very well too..

When you're positioning them.. the way I do it is to hold/tape/secure the surface itself to the component attaching it too.. then I simply lightly pencil my positions.. after that is when I start cutting slots to centers..

There is a tool made just for that too.. Its about $15..maybe $20.. maybe less if you can get one used.. I got one years ago.. when theres a bunch of slots(I'm talking 25-35 hinges or so..) multiply that by 2(one slot each side).. that's 50-70+ slots... the GreatPlane slotter just bores through them.. it takes a tad of practice.. as its a thin blade.. and can skew if its hurried.. but still takes about 4hrs or more work and gets it done in 15-20 minutes.. on the other hand if you like to tinker.. and enjoy the time spent doing it by hand.. that's cool too.. can't knock a craftsman.. so.. one other thing..

Be sure to use "thin" CA glue... it doesn't matter whether its odorless or not.. just make sure its thin.. I put about 5-6 drops on one side while flexing the surface.. then same on the other.. just working the surface for about 5 minutes. it doesn't take alot of glue.. but just be careful to not get too much too quick.. and watch for runs.... less is probably best.. and I do a second app of a few drops after about 15minutes..

There's some good instructs in this thread.. so use whatever works for you.. I'm just sharing what/how I do hinges/slots.. Good luck.

I've had very good results with the setup shown in the attached photos. You obviously need a drill press, but I expect that many of the builders have one. I use the thinnest little circular saw blade I have, about .015 thick, on a mandrel. It's set above the table the right distance to center the slot, or offset it if that's what you want. Just move the control surface toward the saw until it's the right depth. For parkflyers, I just cut the CA hinge into a circular shape. If it's a bigger model, I use either an Xacto or my Great Planes hinge slotter to deepen the slot. Once the cut is started with the saw, it's easy to assure that it continues through the center of the workpiece.

I've used this technique successfully on material as thin as 1/16, and for other types of hinges that neeed a slot. As long as you keep the same side of the surfaces down, a few thousandths error will not affect the alignment of the hinges, They should always come out perfectly aligned. If the material is tapered, you can either make the slot parallel to one of the sides, or shim the piece to cut on the centerline.

One of the photos also shows the little guard I use with the saw, the other has the guard removed so you can see the setup better.

[QUOTE=DGrant;21381789
There is a tool made just for that too.. Its about $15..maybe $20.. maybe less if you can get one used.. I got one years ago.. when theres a bunch of slots(I'm talking 25-35 hinges or so..) multiply that by 2(one slot each side).. that's 50-70+ slots... the GreatPlane slotter just bores through them.. it takes a tad of practice.. as its a thin blade.. and can skew if its hurried.. but still takes about 4hrs or more work and gets it done in 15-20 minutes.. [/QUOTE]

The Great Planes Slot Machine is worth every penny (about 2100 of them). Add in the available cutting guide for 4 bucks, and it makes it hard for even a klutz like me to mess the job up!

Originally Posted by StayQuiet

The Great Planes Slot Machine is worth every penny (about 2100 of them). Add in the available cutting guide for 4 bucks, and it makes it hard for even a klutz like me to mess the job up!

It is a great tool and there are blades for thicker hinges available. Also a cutting guide.


http://www3.towerhobbies.com/cgi-bin...Fb%3E+machines