Assembling the Doors to the Skin using
Roobart Hinges driven by a Mini Servo
There was allot of work to manage this. Not only I had to pour resin mounting blocks to hold the servo I also had to modify the Roobart hinges to achieve my goal. I had it all in my mind but didn't know if it all would fit.
I was searching for another way to open the doors because of the lost in strength servos have when using the classic rods. When I could align the center of the servo with the center of the hinge, there would be no lost in strength.
Unfortunately this (new) way of opening doors can only be used in the body, and with Roobart hinges. Not in the Dome, not with McMaster hinges…
Challenge I: before I really could start with this project I had to be sure I could reproduce the servo axe adapter. I bought some mini servo's and cut of the arms from one of the accessories.
Cut Arm
I managed to create an item witch I had in mind to make a mould from. The black part is the modified servo arm, the yellow part is a inside piece of a ballpoint pen. It was a perfect fit.
I used a lathe to drill right trough the resin duplicate from the above picture. Made it a little shorter, and tapped right trough with an M3 tap. The treated rod is screwed in and glued with a JB-weld kinda compound.
So far so good. This was pretty easy. I had a device witch fit on a mini servo on one side and had an axe to turn the hinge on the other side.
Challenge II: I always liked the double hinge look on the large body doors. This personal preference made me come up with the next idea. I could glue two hinges together with a shaft. If I could lock that shaft on the axe from the above picture, the hinge will turn when the servomotor turns …
Modified the Roobart hinges to “Club Spec”.
Club Spec
When the double hinge was ready I glued them to the skin. This picture shows another double hinge but without the resin adapter. Its because this is the lower (double) hinge. It doesn't need a servo.
I'm not this glue type of guy, but in this case gluing is the best option. While gluing you might have to shift the hinge to correct the alignment with the skins border: very difficult when you just drilled a hole right trough your shiny R2 Skins.
Make sure the turnable piece is aligned, don't mind the alignment of the glued piece.
Time to glue the door to the pivoting part of the hinges. Make sure you align the door with the outer skin: the part witch is visible. Don't align with the borders on the inner skin, it looks easier because you are gluing on the inside. But the result is very disappointing… Ask me how I know.
The last and the most difficult part is to mount de servo in a proper way so he can be removed when necessary (so no glue here). With the hinge construction the only way to mount/demount is from the top. I had to bring up my moulding skills(?) again. I'm not gonna type the whole construction process (boring) but the next picture shows you some.
As you can see I have a large and a short mounting block. The servo is hold in it's place by the two side screws and the pin from the block itself. The other holes are meant to mount the block to the inner skin.
Something like this. I have another mounting block set it's a mirror from this setup to control R2's left large recessed door.
Ouch! Miscalculation: The shoulder mounting block (Frame) is a little to wide to mount the small servo mounting block.
Therefore I've sanded the little mounting block in a shape so it will fit between the frame and the skin.
This is my solution for the small front door. I will cut away some Tec7 afterwards to give it a cleaner look.
I filled off some of the hinge axe. This is where the latch will come. This way the latch will stay in place better. I might drill it in the future if possible…
For a working example, see this video




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