Wed Jul 14 2010

Popup tipup modifications

After some work today, I had the doubler plates fitted to the inside rib of the structure for the left side pivot.

...as well as the outside rib.

UPS delivered my retrofitted servos. This package shows the loving care that was taken when handling the delivery through the UPS system. Sigh.

The servos had been disassembled, the shaft arm was replaced with one that has an integral 5/16 threaded stud, and a self-locking nut was attached. This looks way more robust than the little screw which was previously used. I'd have felt even better if the shaft was cross drilled for a castle nut and cotter pin, but this should be fine.

When looking at the popup tipup modifications, it became clear that I was going to have difficulty getting the bolt in and out of this pivot point. I decided I would need to make an access hole to get the bolt in through one of the ribs. You can see that the pivot arm is being held so the rounded aft end of the 1/8 thick popup arm is concentric with the rounded top surface of the canopy frame. This is the position the popup arm will be in when the canopy is popped up.

I supported the arm by clamping a wood block between the two ribs that the forward end of the arm could rest upon.

...which let me then shift the arm next to the inboard rib and trace the outline of the arm onto the rib. After removing the rib, I used an ultra-fine point sharpie to mark the location of the center point.

Since the 1/4 diameter bolt will require a 7/16 socket, I measured the diameter of one of my sockets to determine how large a hole will be required for socket access. It looks like 11/16 will work out just fine.

When I drilled a #40 pilot hole at the center of the pivot location, I could see that the 11/16 hole was going to consume a neighboring rivet hole. So, in order to prevent this from causing my unibit to shift it's position...

...I clamped on a scrap piece of 1/8 thick stock...

...and drilled through the whole shebang. The thicker material made the effect of the neighboring rivet hole inconsequential, so the hole stayed centered when I drilled through.

Here's the socket access hole after everything has been trimmed up.

...and here it is installed.

Oh, I almost forgot...these are the popup tipup bellcranks which Jim Carruthers silver soldered for me. They came out great and he even bead blasted them afterwards. When Clare relayed these back to me, I thought I would get a "Thank You" card and send to Jim. Unfortunately, the only thank you cards we have in the house have bunnies, flowers, or rainbows on them, so they're not really very appropriate for an industrial-job kind of thanks. I'll figure something out.