rhd-RCU

My Feedback: (36)

Is there a jig for using Robart hinges other than there's. I read in a mag several years ago of someone selling one. It was for getting equal placement of the holes.

majortom

I have the Robart tool, but don't use it. I pair up the two surfaces (stab & elevator, etc.) one on top of the other, and make a vertical tick mark on the facing edges for each hinge position. I then make parallel cuts across the edge on either side of each tick mark, width between the cuts such as to receive the Robart hinge knuckle. I use knifepoint to cut out the little knuckle slots, leaving me with a flat spot where each hinge will go on the beveled edge. I re-do my paired surface tick marks, which I just cut away. I then eyeball the vertical tick and make a cross tick in the center of the thickness of the edge. I then put the point of a center-punch on the cross-marks and make a solid indentation in the wood. These indentations always go straight in, regardless of little grain irregularities in the wood. Now I have a good indentation to keep the point of my drill bit from wandering.

Now I drill each hole, jogging the trigger on the drill and going in slowly, checking by eye for drill going in perpendicular to the edge and centered between top & bottom surface of the piece. This procedure moves along faster than it sounds in this description.

When all holes are drilled, I then use knifepoint again to enlarge the openings from round to square, which is the shape of the hinge point as it blends into the knuckle. Insert all the hinges for dry fit. Hardly ever have to re-work any of the holes. With the knuckle sockets cut out, you should be able to press the surfaces together such that there is virtually zero gap between the bevelled edges.

I then cover my surfaces over the holes, and when the piece is fully covered I cut a little crossmark through the covering over each hole, then seal the covering into the hole with pencil point soldering iron.

I use aliphatic glue, thinned out slightly with water to make it run down the hole, just a couple fat drops is enough. You can get small plastic squeeze bottles at craft or art supply stores, and make up a special batch of aliphatic just for hinges. The aliphatic sets up rather quickly, so if I just push the points in one surface at a time and put the piece aside with the glued points down, I never have any difficulty with glue coming back up into the knuckle.

Ben Diss

My Feedback: (23)

Avoid the use of the Robart jig. Because of the hinging geometry of this tool, it will create a hole that is not centered if the top and bottom of the control surface is not exactly parallel. In other words, if the control surface is has a diminishing width, the hole will not be centered.

-Ben

rhd-RCU

My Feedback: (36)

Thanks guys. I will give it a try. I know these are the best for the large aircraft, but I can never get them line up. Like the blade hinges I just make the slot wider.
Thanks again,
RD

CafeenMan

I use a drill press and don't have any problems. The only two jigs I know about are the Robart jig and the Dubro jig. The Dubro jig is way too flexible to be considered accurate. Here's how I do it:

Robart Hinge Points