Friday, June 26, 2009

Utility Arms and Large Data Port

I spent a good portion of last night installing the utility arms. Yesterday I found some nylon inserts for the utility arms to protect the screw hole from wear from the threads. I built up my hardware and....

It failed.
The nylon insert fit with a number #8-32 screw - the only size I could find with an OD of 1/4", which is the diameter of the hole in the utility arm. Although it seemed like a good fit in the store, when installing it, there was a little bit of play within the insert, and the arm would dip at the unhinged end. I had built the lower arm assembly with standard machine screws, nuts and washers. Problem was, when all was tightened, the arm was evenly horizontal. However, when the arm was opened several times, the components would loosen, and the arm would slump down.

I used a different method on the upper arm, using a modified t-nut at the top. I had to remove the prongs to get it to set as low as possible as the Large Data Port (LDP) needed to sit on top of it. This arm, once tightened, stayed in place. After several attempts at correcting the lower arm, the lightbulb clicked on and I replaced the assembly with one similar to the top arm assembly and.... well, it worked!!

The skins will need some modifying to allow the arm to swing out freely, but otherwise, fit pretty well.
If you look at the unhinged ends of the UT arm carrier, you can see a small bumper on the side wall. This will allow the arm to come back into the proper position and also protect the tip of the arm from colliding with the plastic wall of the frame. They are not visible with the skins installed.
The LDP is installed with double sided tape, left over from my skins. I used a layer of .040" styrene to even the frame area with the t-nut. It's a very strong bond, but I have been able to pry the tape off of styrene with very little damage. The mount is very secure, but in emergency, I can still pry the dataport off if needed.


BASSplayerACE said...

Now that's purdy! It's cool to see how well it's coming along! (And thanks for updating more often)

Calvin Thomas said...

Hey man,
Awesome work on the arms!!!!
That's how I did mine, Letting the pivot rods turns inside the T-nuts.
One thing you will need is alittle slack at the nuts that touch the arm for adjustment up/down.
Not much, But just alittle.
Just got to figure away to attach a servo for movement.